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1187 lines
71 KiB
HTML
1187 lines
71 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:v="urn:schemas-microsoft-com:vml">
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<!-- $Revision$ -->
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<!-- $Author$ -->
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<!-- $Date$ -->
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<head>
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<meta content="en-us" http-equiv="Content-Language" />
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<meta content="text/html; charset=utf-8" http-equiv="Content-Type" />
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<title>The Weewx weather system</title>
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<!-- CSS -->
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<link href="weewx_docs.css" rel="stylesheet" />
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<!-- JavaScript -->
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<script src="samaxesjs.toc-1.3.2.min.js" type="text/javascript"></script>
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<script type="text/javascript">samaxesJS.toc({exclude: 'h4, h5, h6', autoId: true, context: 'technical_content'});</script>
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</head>
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<body>
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<h1 class="title">The <span class="code">weewx</span> weather system<br />
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Version 1.10</h1>
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<h1>Table of Contents</h1>
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<p>For information on customizing <span class="code">weewx</span>, see the separate
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document <a href="customizing.htm"><em>Customizing
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<span class="code">weewx</span></em></a>.</p>
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<p>For instructions on upgrading from various versions, see the separate document
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<em><a href="upgrading.htm">Upgrading <span class="code">weewx</span></a></em>.</p>
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<p>For instructions on porting to the SheevaPlug, see the separate document
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<em><a href="sheeva.htm">Notes on porting <span class="code">weewx</span> to
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the SheevaPlug</a></em>.</p>
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<div id="technical_content">
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<div id="toc">
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</div>
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<h1><a name="Copyright">Copyright</a></h1>
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<p>(c) 2009, 2010, 2011 by Tom Keffer <<a href="mailto:tkeffer@gmail.com">tkeffer@gmail.com</a>></p>
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<p>This program is free software: you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later version.
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</p>
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<p>This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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</p>
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<p>You should have received a copy of the GNU General Public License along with
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this program. If not, see <http://www.gnu.org/licenses/>
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<a href="http://www.gnu.org/licenses/">http://www.gnu.org/licenses</a>.</p>
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<h1><a name="About_weewx">About <span class="code">weewx</span></a></h1>
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<p><span class="code">weewx</span> is a piece of software, written in
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<a href="http://www.python.org">Python</a>, that interacts with your weather
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station to produce plots, reports, and HTML pages. It can optionally upload
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the reports to a remote Web server as well as publish to the
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<a href="http://www.wunderground.com">WeatherUnderground</a> or
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<a href="http://www.pwsweather.com/">PWSweather.com</a>. It uses modern software
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concepts, making it simple, robust, and easy to extend. For an example station
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see <a href="http://www.threefools.org/weewx">Hood River West</a>.</p>
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<p>Key features:</p>
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<ul>
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<li>An easy to understand, simple, extensible micro-kernel architecture<em>;</em></li>
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<li>Uploads to popular weather sites, such as Weather Underground and CWOP;</li>
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<li>Uploads to your website using FTP;</li>
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<li>Support for multiple <em>skins</em>;</li>
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<li>Simple, but extensible templating system;</li>
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<li>Support for multiple unit systems;</li>
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<li>Calibration corrections;</li>
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<li>Ability to extend <span class="code">weewx</span> with new services
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and reports.</li>
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</ul>
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<p>I wrote <span class="code">weewx</span> over the winter of 2008-2009 for
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two reasons: it was a wet and miserable winter here in Oregon with not much
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else to do, so there was no good reason not to, and because I wanted a simple,
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easy-to-understand server to run my Davis VantagePro2 weather station on a Linux
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box. I had been using <a href="http://www.wviewweather.com/">wview</a>, which
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is a high-performance and feature rich system authored by Mark Teel with lots
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of users. Written in C, it's an efficient system that can run on underpowered
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boxes. In exchange, it's huge (45,000+ lines of code), tightly integrated in
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with its companion library, radlib (another 14,000+ lines), and very complex,
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making it difficult to understand and reliably customize. I wanted something
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more modern and much simpler.</p>
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<p>Having made a career in C++ and Java, I was also interested in some more
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modern languages, so I thought I'd try either Python or Ruby (although, truth
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be told, the roots of Python are nearly as old as C++!). I ended up picking
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Python because its libraries are more mature and there are many mores choices
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for third party libraries.</p>
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<p><span class="code">Weewx</span> weighs in at well under 5,000 lines of code.
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It also has another 2,900 comment lines. Because it is pure Python, it requires
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no makefiles, no builds, no special installs. It offers very powerful configuration
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and templating options, as well as an internally extensible engine, making it
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easy to customize. Its internal modular design and use of modern exception handling
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make it very robust and difficult to crash. It is also architecturally very
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simple and easy to understand. However, to be fair, at this point it supports
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only the
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<a href="http://www.davisnet.com/weather/products/vantagepro.asp">Davis VantagePro2</a>
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weather station.</p>
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<h1><a name="Downloading_weewx">Downloading <span class="code">weewx</span></a></h1>
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<p><span class="code">Weewx</span> can be downloaded from its
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SourceForge page:<a href="http://sourceforge.net/projects/weewx/">http://sourceforge.net/projects/weewx/</a>.
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</p>
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<h1><a name="Prerequisites">Prerequisites</a></h1>
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<h2>Python</h2>
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<p>Python V2.5 or V2.6 is required. The newer V3.0 distribution will not work.</p>
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<h2>External packages</h2>
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<p>The following external packages are required to use <span class="code">weewx</span>.</p>
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<ol>
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<li><a href="http://www.sqlite.org/">sqlite3</a> (Version 3.5 or greater)
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A SQL database written in C, which <span class="code">weewx</span> uses
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to store data pulled from the weather station. Comes with Debian and many
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other Linux distributions.</li>
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<li><a href="http://pypi.python.org/pypi/pysqlite/">pysqlite</a> (Version
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2.5 or greater) The Python interface to sqlite3.</li>
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<li><a href="http://pypi.python.org/pypi/configobj/">configobj</a> (Version
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4.5 or greater) Manages the configuration file <span class="code">weewx.conf</span>.</li>
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<li><a href="http://pypi.python.org/pypi/pyserial">pyserial</a> (Version
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2.3 or greater) Manages the serial connection to the weather station.</li>
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<li><a href="http://www.cheetahtemplate.org">Cheetah</a> (Version 2.0 or
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greater) The HTML templating engine.</li>
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<li><a href="http://pypi.python.org/pypi/PIL">Python Imaging Library</a>
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(Version 1.1.6 or greater) Also known as PIL, this is included in many Python
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distributions.</li>
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</ol>
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<p>In addition, there is one optional package:</p>
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<ul>
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<li><a href="http://rhodesmill.org/pyephem">pyephem</a> (Version V3.7.3
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or greater). For extended almanac information. If not installed,
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fallback information will be used. As of the time of this writing, this
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package could only be installed using <span class="code">easy_install</span>.</li>
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</ul>
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<p>There are two general strategies for installing these prerequisites:</p>
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<ol>
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<li>Use operating system tools, such as <span class="code">apt-get</span>
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(or its graphical equivalent Synaptic Package Manager) for Debian/Ubuntu
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or <span class="code">yast</span> for SuSE; or</li>
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<li>Use the Python tool <span class="code">
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<a href="http://pypi.python.org/pypi/setuptools">easy_install</a></span>.</li>
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</ol>
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<p>Option #1 is easier, but if your Linux distribution does not come with such
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tools, you may have to use <span class="code">easy_install</span>. If you
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choose to install <a href="http://rhodesmill.org/pyephem">pyephem</a>, then
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it can only be installed using <span class="code">easy_install</span> (<a href="#Installing_pyephem">see
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instructions below</a>).</p>
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<p>Brief instructions
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for both approaches are given below.</p>
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<h3>Installation on Debian distributions (including Ubuntu) using
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<span class="code">apt-get</span></h3>
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<p>The instructions that follow are for using the Debian tool
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<span class="code">apt-get</span>, but the same package names would be used
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should you chose to use a graphical interface such as the Synaptic Package Manager.</p>
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<p>To install the required packages:</p>
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<p class="tty">sudo apt-get install sqlite3<br />
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sudo apt-get install python-pysqlite2<br />
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sudo apt-get install python-configobj<br />
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sudo apt-get install python-serial<br />
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sudo apt-get install python-cheetah<br />
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sudo apt-get install python-imaging</p>
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<p>Note that <span class="code">sqlite3</span> and the <span class="code">
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python-imaging</span> (PIL) packages are preinstalled on many Debian
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distributions so the corresponding commands may not do anything.</p>
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<h3>Installation on SuSE using <span class="code">yast</span></h3>
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<p>My SuSE 11.3 system came with some of the prerequisites installed, some available
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through <span class="code">yast</span>, and some that required
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<span class="code">easy_install</span>. </p>
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<p>To start, some packages want to install themselves into
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<span class="code">/usr/local/lib/python2.6/site-packages</span>, which may
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or may not exist. If it does not, you may have to create it before
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running <span class="code">easy_install</span>:</p>
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<pre>sudo mkdir /usr/local/lib/python2.6</pre>
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<pre>sudo mkdir /usr/local/lib/python2.6/site-packages</pre>
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<p>Install the
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gcc compiler:</p>
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<pre>sudo yast -i gcc</pre>
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<p>Then install <span class="code">easy_install</span>:</p>
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<pre>sudo yast -i python-setuptools</pre>
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<p>Install <span class="code">configobj</span>:</p>
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<pre>sudo yast -i python-configobj</pre>
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<p>Install PIL:</p>
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<pre>sudo yast -i python-imaging</pre>
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<p>Install <span class="code">pyserial</span>:</p>
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<pre>sudo yast -i python-serial</pre>
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<p>Install <span class="code">sqlite3</span>. My SuSE 11.3 system came with V3.6.4, which works just fine. However, if
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you need to install:</p>
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<p class="tty">sudo yast -i sqlite3</p>
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<p>Install the Python development package (need for <span class="code">
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pysqlite</span>):</p>
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<pre>sudo yast -i python-devel</pre>
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<p>Install <span class="code">pysqlite</span>:</p>
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<pre>easy_install pysqlite</pre>
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<p>Install <span class="code">Cheetah</span>:</p>
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<pre>easy_install Cheetah</pre>
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<h3>Installation using <span class="code">easy_install</span></h3>
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<p>An alternative approach to installing the required packages is by using the
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Python setup tool "<span class="code">easy_install</span>", part of the
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<a href="http://pypi.python.org/pypi/setuptools">python-setuptools package</a>.
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Refer to their instructions on how to install this tool.</p>
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<p>Once <span class="code">easy_install</span> has been installed, installing
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the rest of the packages is very easy.</p>
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<p>My Ubuntu 8.10 system came with sqlite V3.5.9, which works just fine. If
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you do not have sqlite3, refer to <a href="http://www.sqlite.org">the sqlite
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webpage</a> for installation instructions.</p>
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<p>While Version 2.3.X of <a href="http://pypi.python.org/pypi/pysqlite/">pysqlite</a>
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is included with many versions of Python, the more recent 2.5.X or greater is
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required in order to take advantage of transaction contexts. Hence, you may
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have to install or upgrade. Because pysqlite builds a C library, you may have
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to install the Python development environment first, if you have not already
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done so. Generally, this means installing the gcc compiler. You may also have
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to install the sqlite3 development environment as well.</p>
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<p>With the development environment in place, you can easily build and install
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pysqlite:</p>
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<pre>easy_install pysqlite</pre>
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<p>If your system already has a version of pysqlite installed, but it is not
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a high enough version (<span class="code">easy_install</span> will tell you
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the version you have), then you may have to force an upgrade:</p>
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<pre>easy_install --upgrade pysqlite</pre>
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<p>Note that at the time of this writing (24 Oct 2009), the hosting site for
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pysqlite has changed to one on <a href="http://pysqlite.googlecode.com">googlecode</a>,
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and <span class="code">easy_install</span> could not find it. You may have to
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find and give the URL explicitly to <span class="code">easy_install</span> (adjust
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version numbers as necessary):</p>
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<pre>easy_install http://pysqlite.googlecode.com/files/pysqlite-2.5.5.tar.gz</pre>
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<p>The other packages are straightforward. Install configobj:</p>
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<pre>easy_install configobj</pre>
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<p>Install pyserial:</p>
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<pre><span class="code">easy_install pyserial</span></pre>
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<p>Install Cheetah:</p>
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<pre><span class="code">easy_install Cheetah</span></pre>
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<p>My version of Python came with V1.1.6, which works great, but if you need
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to install</p>
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<pre>easy_install pil</pre>
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<p><a name="Installing_pyephem"></a>If you choose to install the optional
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package pyephem:</p>
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<pre>easy_install pyephem</pre>
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<h2>System requirements</h2>
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<p>I run <span class="code">weewx</span> on a 500MHz system with an AMD Geode
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processor and 512 MB of memory. Configured this way, it consumes about
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5% of the CPU and about 40MB of total memory.</p>
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<h2>Weather station hardware requirements</h2>
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<p>At this point, only the
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<a href="http://www.davisnet.com/weather/products/vantagepro.asp">Davis VantagePro2</a>
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is supported, and even then, only the "Revision B" version (firmware dated on
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or after 22 April 2002). It would be very easy to port to a "Revision A" station
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or even the original VantagePro, but I don't have access to the hardware to
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test it.</p>
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<h1><a name="Installing_weewx">Installing <span class="code">weewx</span></a></h1>
|
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<p>Because <span class="code">weewx</span> is "Pure Python", that is it is 100%
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Python with no "C" modules to compile, installing it is very easy. Furthermore,
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it uses the standard Python
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<a href="http://docs.python.org/install/index.html">distutils</a> install method,
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which is very easy and flexible. Detailed instructions follow.</p>
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<h2>Unpacking</h2>
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<p>Start by unpack the tar ball (substitute your version for X.Y.Z) into any
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convenient directory where you have write permission</p>
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<p class="tty">tar xvf weewx-X.Y.Z</p>
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<p>Then change directory into it:</p>
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<p class="tty">cd weewx-X.Y.Z</p>
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<h2>Choosing where to install <span class="code">weewx</span></h2>
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<p>Next step is figuring out where you want to install <span class="code">weewx</span>.
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If <span class="code"><em>$WEEWX_INSTALL</em></span> symbolizes the root location
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of where the <span class="code">weewx</span> directory will be installed, then
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the nominal directory layout is:</p>
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<table align="center" style="width: 60%">
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<tr>
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<td><strong>Subdirectory</strong></td>
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<td><strong>Contents</strong></td>
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</tr>
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<tr>
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<td><span class="code"><em>$WEEWX_INSTALL</em>/bin</span></td>
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<td>Python packages and scripts</td>
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</tr>
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<tr>
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<td><span class="code"><em>$WEEWX_INSTALL</em>/weewx.conf</span></td>
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<td>Configuration file</td>
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</tr>
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<tr>
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<td><span class="code"><em>$WEEWX_INSTALL</em>/skins</span></td>
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<td>Template skins and their configuration files</td>
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</tr>
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<tr>
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<td><span class="code"><em>$WEEWX_INSTALL</em>/archive</span></td>
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<td>sqlite3 archive and statistical databases</td>
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</tr>
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<tr>
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<td><span class="code"><em>$WEEWX_INSTALL</em>/public_html</span></td>
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<td>Generated HTML and .PNG images</td>
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</tr>
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</table>
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<p>By default, the location for <span class="code"><em>WEEWX_INSTALL</em></span>
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is <span class="code">/home/weewx</span>. However, it can be changed by editing
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the file <span class="code">setup.cfg</span>. If you wish to install someplace
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else, open up <span class="code">setup.cfg</span> and change the line</p>
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<p class="tty">home = /home/weewx</p>
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<p>to reflect your decision.</p>
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<h2>Build and install</h2>
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<p>Build the distribution</p>
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<p class="tty">./setup.py build</p>
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<p>(Because <span class="code">weewx</span> is pure Python this doesn't actually
|
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build anything, but it does arrange files for the final installation)</p>
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<p>Then install it. If you have write permission in the directory where
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<span class="code">weewx</span> will go (<em>i.e.</em>, <span class="code">
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<em>$WEEWX_INSTALL</em></span>), then type</p>
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<p class="tty">./setup.py install</p>
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<p>Otherwise, if you do not have write permission, you will have to use sudo:</p>
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<p class="tty">sudo ./setup.py install</p>
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<h3>Upgrading</h3>
|
|
<p>Before upgrading from a previous version of <span class="code">weewx</span>,
|
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check the upgrade notes, found in file <a href="upgrading.htm">upgrading.htm</a>,
|
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to see if there any specific actions you need to do. </p>
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<p>You then generally follow the procedure above. </p>
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<p><strong>In particular, before starting, be sure to set </strong>
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<span class="code"><strong>home</strong></span><strong> in the file </strong>
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<span class="code"><strong>setup.cfg</strong></span><strong>. </strong></p>
|
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<p>The build and install process will do the following for you.</p>
|
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<ul>
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<li>Save your old '<span class="code">bin</span>' subdirectory as
|
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<span class="code"><em>$WEEWX_INSTALL</em>/bin.YYYYMMDDHHMMSS</span> where
|
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YYYYMMDDHHMMSS is a timestamp;</li>
|
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<li>Install the new version in the '<span class="code">bin</span>'
|
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subdirectory, while preserving any user extensions in the '<span class="code">bin/user</span>'
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subdirectory;</li>
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<li>Save a copy of your old <span class="code">weewx.conf</span> as
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<span class="code"><em>$WEEWX_INSTALL</em>/weewx.conf.YYYYMMDDHHMMSS;</span></li>
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<li>Merge any changes you've made to your old configuration file
|
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<span class="code">weewx.conf</span> into the new configuration file, then
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install the merged copy (this effectively causes changes you've made to
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override the values in the shipped version of <span class="code">weewx.conf</span>);</li>
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<li>Install a <span class="code">'skins'</span> subdirectory if one does
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not already exist.</li>
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</ul>
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<h2>Permissions</h2>
|
|
<p>Strictly speaking it is not necessary to install or run
|
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<span class="code">weewx</span> with root privileges. You only need read/write
|
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access to the serial port for your hardware. For example, if your hardware has
|
|
a USB interface, on Ubuntu and SuSE:</p>
|
|
<p class="tty">sudo chmod a+rw /dev/ttyUSB0</p>
|
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<p>Once done, if you edit <span class="code">setup.cfg</span> to install into
|
|
a directory where you have write permissions, you can install and run
|
|
<span class="code">weewx</span> without any root privileges at all. </p>
|
|
<h2>Final note on installation</h2>
|
|
<p>Because <span class="code">weewx</span> is pure Python, it does not actually
|
|
have to be "built" and "installed" at all! You can just simply run it out of
|
|
whatever directory you unpack it into. However, it must still be told where
|
|
to find the skin templates and databases, as well as where to put the generated
|
|
HTML files and plot images. This is done by setting <span class="code">WEEWX_ROOT</span>
|
|
in <span class="code">weewx.conf</span> to reflect where your data files can
|
|
be found (normally, the install process does this for you):</p>
|
|
<pre>> # Edit WEEWX_ROOT to reflect the location of your data hierarchy:
|
|
> vi ./weewx-X.Y.Z/weewx.conf
|
|
> # Now run weewxd.py out of the directory you unpacked weewx into:
|
|
> ./weewx-X.Y.Z/bin/weewxd.py ./weewx-X.Y.Z/weewx.conf</pre>
|
|
<h1><a name="Configuring_weewx">Configuring <span class="code">weewx</span></a></h1>
|
|
<p>This section covers configuring <span class="code">weewx</span>, in particular
|
|
the configuration files <span class="code">weewx.conf</span> and
|
|
<span class="code">skin.conf</span>.</p>
|
|
<p>In the following, <span class="code"><em>$WEEWX_ROOT</em></span> refers to
|
|
the <span class="code">weewx</span> data root directory, generally
|
|
<span class="code">/home/weewx</span>. The subdirectories <span class="code">
|
|
archive</span>, <span class="code">skins</span>, and <span class="code">public_html</span>
|
|
are expected to be found here. </p>
|
|
<h2>Moving from wview</h2>
|
|
<p>NOTE: This section is necessary only if you are moving from
|
|
<a href="http://www.wviewweather.com/">wview</a> to <span class="code">weewx</span>
|
|
and wish to transfer your old data over. If you are starting afresh, you do
|
|
not need to follow this section — the two main databases are created and populated
|
|
automatically by <span class="code">weewx</span>.</p>
|
|
<p>The main archive database can be just copied over because wview and
|
|
<span class="code">weewx</span> use identical schemas:</p>
|
|
<pre>mkdir <em>$WEEWX_ROOT</em>/archive
|
|
cp /usr/local/var/wview/archive/wview-archive.sdb <span class="code"><em>$WEEWX_ROOT</em></span>/archive/weewx.sdb</pre>
|
|
<p>The second database, the statistics, will then be automatically created and
|
|
backfilled on startup of weewx. If your existing database is large, backfilling
|
|
could take some time. On my modest 500 MHz
|
|
<a href="http://www.fit-pc.com/new/fit-pc-slim-specifications.html">fit-PC Slim</a>
|
|
with 512 MB of memory it took a little over 4 minutes for a year and a half
|
|
(25 MB) of data.</p>
|
|
<h2>Configuring your weather station</h2>
|
|
<p>The only two variables <span class="code">weewx</span> tries to manage on
|
|
the VantagePro are the time and the archive interval. </p>
|
|
<h3>Time</h3>
|
|
<p>The time on the VP is automatically synchronized with the
|
|
<span class="code">weewx</span> server nominally every four hours (changeable
|
|
by the user). You should run a <a href="http://www.ntp.org/">NTP</a> daemon
|
|
on your server to insure that it is synchronized with the correct time. Doing
|
|
so will greatly reduce errors, especially if you send data to services such
|
|
as the Weather Underground.</p>
|
|
<h3><a name="Archive_interval">Archive interval</a></h3>
|
|
<p>The archive interval is set in the main configuration file
|
|
<span class="code"><em>$WEEWX_ROOT</em>/weewx.conf. </span>Look for the entry
|
|
<span class="code">archive_interval</span> in the <span class="code">VantagePro</span>
|
|
section. Set it to the number of seconds. Valid entries are 60, 300, 600, 900,
|
|
1800, 3600, and 7200. However, if you are ftp'ing lots of files to a server,
|
|
setting it to 60 seconds may not give enough time to have them all uploaded
|
|
before the next archive record is due. If this is the case, you should pick
|
|
an archive interval of at least 300 seconds, or trim the number of files you
|
|
are using.</p>
|
|
<p>I have found that a five minute (300 seconds) archive interval works well
|
|
for the VantagePro. Because of the large amount of onboard memory it carries,
|
|
going to a larger interval really does not have any advantages.</p>
|
|
<p><em>Choose your archiving interval carefully! </em>Once chosen, it cannot
|
|
be changed without messing up your statistics (highs and lows will be OK, but
|
|
averages and rms wind speed will be wrong).</p>
|
|
<p>After setting the desired interval in the configuration file, run the
|
|
<span class="code">configure.py</span> script to set it on the VantagePro. If
|
|
it differs from the old archive interval, the main memory log of the VantagePro
|
|
will be cleared. </p>
|
|
<p class="tty"><em>$WEEWX_ROOT</em>/bin/configure.py --configure-VantagePro
|
|
$WEEWX_ROOT/weewx.conf</p>
|
|
<h2>Editing the configuration file <span class="code">weewx.conf</span></h2>
|
|
<p>Station specific information is set in the configuration file
|
|
<span class="code"><em>$WEEWX_ROOT</em>/weewx.conf</span>. There is another
|
|
configuration file <span class="code">skin.conf</span> for presentation-specific
|
|
options, which is described in a separate document <em>
|
|
<a href="customizing.htm">Customizing <span class="code">weewx</span></a>
|
|
</em>under section <em>
|
|
<a href="customizing.htm#Reference:_The_Standard_skin_configuration_file">Reference:
|
|
The standard skin configuration file</a></em>.</p>
|
|
<p>Most of the important options are up near the top of the file. They are all
|
|
documented in this section, although you can safely ignore most of them. The
|
|
truly important ones, the ones you are likely to have to customize for your
|
|
station, are shown in <span class="bold_n_blue"><strong>bold face and in blue</strong></span>.
|
|
</p>
|
|
<p>Default values are provided for many of them, meaning that if they are not
|
|
listed in the configuration file <em>at all</em>, <span class="code">weewx</span>
|
|
will pick sensible values. When the documentation below gives a "default value"
|
|
this is what it means. However, all options have been given values in the configuration
|
|
file that ships with <span class="code">weewx</span>, so you can see what they
|
|
look like. The value given in this shipped configuration file is not necessarily
|
|
the same as the "default value".</p>
|
|
<p>What follows is organized by the different sections of the configuration
|
|
file.</p>
|
|
<h3>General</h3>
|
|
<p>The options declared at the top are not actually part of any section. There
|
|
are two:</p>
|
|
<p class="config_option">debug</p>
|
|
<p>Set to 1 to have the program perform extra debug checks, as well as emit
|
|
extra information on the log file. Otherwise, set to 0. Default is 0 (no debug).</p>
|
|
<p class="config_option">socket_timeout</p>
|
|
<p>Set to how long to wait before declaring a socket time out. This is used
|
|
when FTP'ing data to a web server or sending data to the Weather Underground.
|
|
Twenty (20) seconds is reasonable. Default is 20.</p>
|
|
<h3 class="config_section">[Station]</h3>
|
|
<p>This section covers options relating to the entire weather station setup.
|
|
</p>
|
|
<p class="config_important">WEEWX_ROOT</p>
|
|
<p>Set to the root directory of the <span class="code">weewx</span> data file
|
|
hierarchy for this station, nominally '<span class="code">/home/weewx</span>'.
|
|
The weewx data subdirectories <span class="code">skins</span>,
|
|
<span class="code">archive</span>, and <span class="code">public_html</span>
|
|
are expected to be found here. This value will be set automatically by the setup
|
|
script <span class="code">setup.py</span> to reflect the choice you made in
|
|
the configuration file <span class="code">setup.cfg</span>. Required. No default.</p>
|
|
<p class="config_important">location</p>
|
|
<p>The station location should be a UTF-8 string that describes the geography
|
|
of where you weather station is located, such as '<span class="code">Hood River,
|
|
Oregon</span>'. Required. No default.</p>
|
|
<p class="config_important">latitude<br />
|
|
longitude</p>
|
|
<p>The lat/lon should be set in decimal degrees, negative for southern and eastern
|
|
hemispheres, respectively. Required. No default.</p>
|
|
<p class="config_important">altitude</p>
|
|
<p>Set to the altitude of the station and the unit used for the altitude. Required.
|
|
No default. Example:</p>
|
|
<pre>altitude = 700, foot</pre>
|
|
<p class="config_important">rain_year_start</p>
|
|
<p>If your area uses a rain year that starts on something other than the first
|
|
of January, you may want to set this variable. For example, set to 10 if your
|
|
rain year starts in October (as mine does). Default is 1.</p>
|
|
<p class="config_option">week_start</p>
|
|
<p>Start of the week. 0=Monday, 1= Tuesday, ... , 6 = Sunday. Default is 6 (Sunday)</p>
|
|
<p class="config_option">clock_check</p>
|
|
<p>How often to check the station's onboard clock for drift, in seconds. Default
|
|
is 14400 (every 4 hours)</p>
|
|
<p class="config_option">max_drift</p>
|
|
<p>The maximum amount of drift to tolerate, in seconds, in the onboard clock,
|
|
before resetting the clock. Default is 5.</p>
|
|
<p class="config_option">cache_loop_data</p>
|
|
<p>Set to 1 (one) to cache LOOP data, otherwise, set to zero. Most users will
|
|
not want to change this unless you have a specialized application. Default is
|
|
1 (<em>i.e.</em>, cache LOOP data).</p>
|
|
<p class="config_option">station_type</p>
|
|
<p>Set to the type of hardware you are using. For this version, only '<span class="code">VantagePro</span>'
|
|
is accepted. Required.</p>
|
|
<h3 class="config_section">[VantagePro]</h3>
|
|
<p>This section is for options relating to the VantagePro hardware.</p>
|
|
<p class="config_important">port</p>
|
|
<p>Set to the port name used by your station. Example, /<span class="code">dev/ttyUSB0</span>
|
|
is a common location for USB ports under Debian, <span class="code">/dev/ttyS0</span>
|
|
for serial ports. Required. No default.</p>
|
|
<p class="config_option">baudrate</p>
|
|
<p>Set to the baudrate of your station. The default is 19200.</p>
|
|
<p class="config_important">archive_interval</p>
|
|
<p>Set to the desired archive interval of your station, in seconds. This variable
|
|
is only used when setting up your station. Otherwise, this value is read directly
|
|
from the station. Required if you <a href="#Archive_interval">configure your
|
|
station</a>. No default.</p>
|
|
<p class="config_option">iss_id</p>
|
|
<p>Set to the ID number of your Integrated Sensor Suite (ISS). This is used
|
|
in the formula to calculate reception quality for wireless stations. The default
|
|
is 1.</p>
|
|
<p class="config_option">archive_delay</p>
|
|
<p>How long to wait in seconds after the top of an archiving interval before
|
|
fetching new data off the station. For example, if your archive interval is
|
|
5 minutes and archive_delay is set to 15, then the data will be fetched at 00:00:15,
|
|
00:05:15, 00:10:15, etc. This delay is to give the station a few seconds to
|
|
archive the data internally, and in case your server has any other tasks to
|
|
do at the top of the minute. Default is 15 seconds.</p>
|
|
<p class="config_option">timeout</p>
|
|
<p>How many seconds to wait for a response from the station before giving
|
|
up. Default is 5 seconds.</p>
|
|
<p class="config_option">wait_before_retry</p>
|
|
<p>How many seconds to wait before retrying again. Unless you have a good reason
|
|
to change it, this value should be left at the default, as it is long enough
|
|
for the station to offer new data, but not so long as to go into a new loop
|
|
packet (which arrive every 2 seconds). Default is 1.2 seconds.</p>
|
|
<p class="config_option">max_tries</p>
|
|
<p>How many times to try again before giving up. Default is 4.</p>
|
|
<p class="config_option">unit_system</p>
|
|
<p>What unit system is in use on your weather station hardware. Possible values
|
|
are '1' (U.S. Customary) or '2' (Metric). As far as I know, all Davis instruments
|
|
support only U.S.. In any case, U.S. is the only system supported by
|
|
<span class="code">weewx</span> at this time. Default is 1.</p>
|
|
<h3 class="config_section">[RESTful]</h3>
|
|
<p>This section is for configuring uploads to simple
|
|
<a href="http://en.wikipedia.org/wiki/Representational_State_Transfer">RESTful</a>
|
|
servers such as the <a href="http://www.wunderground.com/">Weather Underground</a>,
|
|
<a href="http://www.pwsweather.com/">PWSweather.com</a>, or
|
|
<a href="http://www.wxqa.com/">CWOP</a>.</p>
|
|
<h4 class="config_section">[[Wunderground]]</h4>
|
|
<p><span class="code">Weewx </span>can send your current data to the Weather
|
|
Underground. If you do not wish to do this, comment out the two options below.</p>
|
|
<p class="config_important">station</p>
|
|
<p>Set to your Weather Underground station ID (e.g., <span class="code">KORHOODR3</span>).
|
|
Required.</p>
|
|
<p class="config_important">password</p>
|
|
<p>Set to your Weather Underground password. Required.</p>
|
|
<h4 class="config_section">[[PWSweather]]</h4>
|
|
<p><span class="code">Weewx </span>can send your current data to the PWSweather.com
|
|
service. If you do not wish to do this, comment out the two options below.</p>
|
|
<p class="config_important">station</p>
|
|
<p>Set to your PWSweather station ID. Required.</p>
|
|
<p class="config_important">password</p>
|
|
<p>Set to your PWSweather password. Required.</p>
|
|
<h4 class="config_section">[[CWOP]]</h4>
|
|
<p><span class="code">Weewx</span> can send your data to the Citizen Weather
|
|
Observer Program. If you do not wish to do this, comment out option "<span class="code">station</span>"
|
|
below.</p>
|
|
<p class="config_important">station</p>
|
|
<p>Set to your CWOP station ID (e.g., <span class="code">CW1234</span>). Required.</p>
|
|
<p class="config_important">passcode</p>
|
|
<p>This is used for APRS (amateur radio) stations only. Set to the passcode
|
|
given to you by the CWOP operators. Otherwise, leave this option commented out
|
|
[Required for APRS stations; ignored for others]</p>
|
|
<p class="config_option">server</p>
|
|
<p>A comma separated list of servers:ports to try. Unless you have a good reason
|
|
to change this, use the servers listed. [Required.]</p>
|
|
<p class="config_option">interval</p>
|
|
<p>The interval in seconds between posts. Because CWOP is heavily used, the
|
|
operators discourage very frequent posts. Every 5 minutes (300 seconds) is fine,
|
|
but they prefer every 10 minutes (600 s) or even longer. Setting this value
|
|
to zero will cause every archive record to be posted. [Optional. Default is
|
|
zero.]</p>
|
|
<p class="config_option">stale</p>
|
|
<p>How old a record can be before it will not be used for a catch up. CWOP does
|
|
not use the timestamp on a posted record. Instead, they use the wall clock time
|
|
that it came in. This means that if your station is off the air for a long period
|
|
of time, then weewx attempts a catch up, old data could be interpreted as the
|
|
current conditions. [Optional. Default is 1800 seconds.]</p>
|
|
<h3 class="config_section">[Archive]</h3>
|
|
<p>This section is for configuring the sqlite3 database in which the station
|
|
archive data is stored.</p>
|
|
<p class="config_option">archive_file</p>
|
|
<p>The path, relative to the <span class="code">WEEWX_ROOT </span>directory,
|
|
to the database. Required</p>
|
|
<p class="config_option">unit_system</p>
|
|
<p>What unit system to use inside the database. Required. The only one supported
|
|
right now is '1', the U.S. Customary system</p>
|
|
<h3 class="config_section"><a name="[Stats]">[Stats]</a></h3>
|
|
<p>This section is for configuring the sqlite3 database in which the station
|
|
statistics are stored.</p>
|
|
<p class="config_option">stats_file</p>
|
|
<p>The path, relative to the <span class="code">WEEWX_ROOT </span>directory
|
|
to the statistical database. Required.</p>
|
|
<p class="config_option"><a name="stats_types">stats_types</a></p>
|
|
<p>The list of types for which statistics will be kept. Types not listed will
|
|
not be available for generating HTML pages. Optional. The default is all types,
|
|
resulting in a possibly much bigger than necessary stats database (do you really
|
|
have four different soil moisture sensors?) The list that ships with the configuration
|
|
file will work for most stations and probably will not have to be modified.</p>
|
|
<h3 class="config_section"><a name="[Reports]">[Reports]</a></h3>
|
|
<p>This section controls which reports are to be generated. While it can be
|
|
highly customized for your individual situation, this documentation describes
|
|
the section as shipped in the standard distribution.</p>
|
|
<p>Each report is represented by a sub-section, marked with double brackets
|
|
(<em>e.g.</em>, <span class="code">[[MyReport]]</span>). Any options for the
|
|
report should be placed under it. The standard report service will go through
|
|
the sections, running each report in order. Hence, for the stock distribution,
|
|
report <span class="code">[[StandardReport]]</span> will be run first, then
|
|
report <span class="code">[[FTP]]</span> (which actually optionally uploads
|
|
the results to a remote web server). Details for how to customize reports are
|
|
in the section <em>
|
|
<a href="customizing.htm#Opportunities_for_customizing_reports">Opportunities
|
|
for customizing reports</a></em>, in the document <em>
|
|
<a href="customizing.htm">Customizing <span class="code">weewx</span></a></em>.</p>
|
|
<p class="config_option">SKIN_ROOT</p>
|
|
<p>The directory relative to <span class="code"><em>$WEEWX_ROOT</em></span>
|
|
where the skins live. Default is <span class="code">skins</span>.</p>
|
|
<p class="config_option">HTML_ROOT</p>
|
|
<p>The target directory for the generated files, relative to
|
|
<span class="code"><em>$WEEWX_ROOT</em></span>. Generated files and images will
|
|
be put here. Default is <span class="code">public_html</span>.</p>
|
|
<h4 class="config_section">[[StandardReport]]</h4>
|
|
<p>This is the standard report that will be run on every archiving interval.
|
|
It uses the skin "<span class="code">Standard</span>", which generates four
|
|
HTML pages ("day", "week", "month", and "year" observations), plot graphs for
|
|
same, an RSS feed, and NOAA monthly and yearly reports. Unless changed otherwise,
|
|
it uses US Customary Units and puts the results in <span class="code">public_html</span>
|
|
and subdirectory <span class="code">public_html/NOAA</span>.</p>
|
|
<h4 class="config_section">[[FTP]]</h4>
|
|
<p>While this "report" doesn't actually generate anything, it uses the report
|
|
machinery to upload files from directory <span class="code"><em>$HTML_ROOT</em></span>
|
|
to a remote webserver. It does an incremental update, that is, it only FTPs
|
|
any files that have changed, saving the outgoing bandwidth of your Internet
|
|
connection.</p>
|
|
<p>If you do not use such a server, comment out the first four options below.</p>
|
|
<p class="config_important">user</p>
|
|
<p>Set to the username you use for your FTP connection to your web server. Required.
|
|
No default.</p>
|
|
<p class="config_important">password</p>
|
|
<p>Set to the password you use for your FTP connection to your web server. Required.
|
|
No default.</p>
|
|
<p class="config_important">server</p>
|
|
<p>Set to the name of your web server (e.g.,
|
|
<a href="http://www.threefools.org">www.threefools.org</a>, in my case). Required.
|
|
No default</p>
|
|
<p class="config_important">path</p>
|
|
<p>Set to the path where the weather data will be stored on your webserver (e.g.,
|
|
'<span class="code">/weather</span>'). NB: some FTP servers require a leading
|
|
slash ('<span class="code">/</span>'), some don't. Required. No default.</p>
|
|
<p class="config_important">passive</p>
|
|
<p>Set to 1 if you wish to use the more modern, FTP passive mode, 0 if you wish
|
|
to use active mode. Passive mode generally works better through firewalls, but
|
|
not all FTP servers do a good job of supporting it. See
|
|
<a href="http://slacksite.com/other/ftp.html">Active FTP vs. Passive FTP, a
|
|
Definitive Explanation</a> for a good explanation of the difference. Default
|
|
is 1 (passive mode).</p>
|
|
<p class="config_option">max_tries</p>
|
|
<p><span class="code">Weewx</span> will try up to this many times to FTP a file
|
|
up to your server before giving up. Default is 3.</p>
|
|
<h3 class="config_section">[<a name="Calibrate">Calibrate</a>]</h3>
|
|
<p>One of the services that <span class="code">weewx</span> can run is a <em>
|
|
calibration service</em> called <span class="code">StdCalibrate</span>. This
|
|
service offers an opportunity to correct for any calibration errors in your
|
|
instruments. It is very general and flexible.</p>
|
|
<p>If you do not wish to apply any calibrations, you can leave it out of
|
|
<span class="code"><a href="#service_list">service_list</a></span>, the list
|
|
of services to be run, and it will not be loaded or run.</p>
|
|
<h4 class="config_section">[[Corrections]]</h4>
|
|
<p>In this section you list all <em>correction expressions</em>. For example,
|
|
say that you know your outside thermometer reads high by 0.2°F. You could add
|
|
the expression:</p>
|
|
<pre>outTemp = outTemp - 0.2</pre>
|
|
<p>Perhaps you need a linear correction around a reference temperature of 68°F:</p>
|
|
<pre>outTemp = outTemp + (outTemp-68) * 0.02</pre>
|
|
<p>It is even possible to do corrections involving more than one variable. Suppose
|
|
you have a temperature sensitive barometer:</p>
|
|
<pre>barometer = barometer + (outTemp-32) * 0.0091</pre>
|
|
<p>All correction expressions are run in the order given.</p>
|
|
<p>The units should be <em>in the native units of the instrument</em>, US Customary
|
|
in the case of the VantagePro.</p>
|
|
<p>Both LOOP data and archive data will be corrected. It is important that the
|
|
calibration service, <span class="code">StdCalibrate</span>, be run <em>before</em>
|
|
the archiving service <span class="code">StdArchive</span>, so that it is the
|
|
corrected data that is stored.</p>
|
|
<p>If all you require is a simple correction offset, this can also be done in
|
|
the Davis VantagePro hardware. See your manual for instructions.</p>
|
|
<h3 class="config_section">[<a name="QC">QC</a>]</h3>
|
|
<p>Another service that weewx can run is a <em>quality control service</em>
|
|
called <span class="code">StdQC</span>. This service is very simple and only
|
|
checks that values are within a minimum and maximum range.</p>
|
|
<p>If you do not wish to use this service, you can leave it out of
|
|
<span class="code"><a href="#service_list">service_list</a></span>, the list
|
|
of services to be run, and it will not be loaded or run.</p>
|
|
<h4 class="config_section">[[MinMax]]</h4>
|
|
<p>In this section you list the observation types you wish to have checked,
|
|
along with their minimum and maximum values. The units should be in the native
|
|
units of the weather station hardware (<em>e.g.</em>, US Customary in the case
|
|
of the Davis VantagePro2). For example,</p>
|
|
<p class="tty">[[MinMax]]<br />
|
|
outTemp = -40, 120<br />
|
|
barometer = 28, 32.5<br />
|
|
outHumidity = 0, 100</p>
|
|
<p>In this example, if a temperature should fall outside of the inclusive range
|
|
-40 °F through 120 °F, then it will be set to the null value,
|
|
<span class="code">None</span> and ignored. In a similar manner, the acceptable
|
|
values for barometric pressure would be 28 through 32.5 inHg, for humidity 0
|
|
through 100%.</p>
|
|
<p>Both LOOP and archive data will be checked. It is important that the quality
|
|
control service be run <em>after</em> the calibration service
|
|
<span class="code">StdCalibrate</span> and <em>before</em> the archiving service
|
|
<span class="code">StdArchive</span>, so that it is the calibrated data that
|
|
is checked and then stored.</p>
|
|
<p>Knowing the details of how your hardware encodes data helps to minimize the
|
|
number of observations that need to be checked. For example, the VP2 devotes
|
|
only one unsigned byte to storing wind speed, and even then
|
|
<span class="code">0xff</span> is devoted to a bad value, so the only possible
|
|
values that could appear are 0 through 126 mph, a reasonable range. So, there
|
|
is no real point in checking wind speed for these instruments.</p>
|
|
<h3 class="config_section">[Engines]</h3>
|
|
<p>This section is used to configure the internal service engine in weewx. It
|
|
is for advanced customization. Details on how to do this is found in the section
|
|
<em>
|
|
<a href="file://RAVEN/tkeffer/workspace/weewx/docs/customizing.htm#Customizing_the_weewx_service_engine">
|
|
Customizing the weewx service engine</a> </em>in the document
|
|
<a href="customizing.htm"><em>Customizing </em><span class="code"><em>weewx</em></span></a>.</p>
|
|
<h4 class="config_section">[[WxEngine]]</h4>
|
|
<p>This section is for options used by the service engine.</p>
|
|
<p class="config_option"><a name="service_list">service_list</a></p>
|
|
<p>This option is the list of <em>services</em> that are to be run by the service
|
|
engine. After each event (such as the arrival of LOOP data, etc.), they will
|
|
be run in the given order. The standard list of services run by weewx is:</p>
|
|
<p class="tty">service_list = weewx.wxengine.StdCalibrate, weewx.wxengine,StdQC,
|
|
weewx.wxengine.StdArchive, weewx.wxengine.StdTimeSynch, weewx.wxengine.StdPrint,
|
|
weewx.wxengine.StdRESTful, weewx.wxengine.StdReportService</p>
|
|
<p>You can leave some of these services out if you do not need them. However,
|
|
this will only make a slight difference in execution speed.</p>
|
|
<h1><a name="Running_weewx">Running <span class="code">weewx</span></a></h1>
|
|
<p><span class="code">Weewx</span> can be run either from the command line (useful
|
|
for diagnostic purposes because it will print out a summary of every LOOP data),
|
|
or as a daemon. When first trying <span class="code">weewx</span>, it's probably
|
|
best to run it from the command line because you will be able to see command
|
|
line diagnostics, as well as log messages.</p>
|
|
<h2>Running from the command line</h2>
|
|
<p><span class="code">Weewx</span> can easily be run from the command line.
|
|
Start by making sure you have appropriate permissions to the serial port your
|
|
weather station uses. For example, if you are using a plain old serial port:</p>
|
|
<p class="tty">sudo chmod 666 /dev/ttyS0</p>
|
|
<p>Then run the main loop program, <span class="code">weewxd.py</span>, giving
|
|
the configuration file as its only parameter:</p>
|
|
<p class="tty"><em>$WEEWX_ROOT</em>/bin/weewxd.py <em>$WEEWX_ROOT</em>/weewx.conf</p>
|
|
<p>It should start by downloading any archive data from your weather station
|
|
into the database <span class="code"><em>$WEEWX_ROOT</em>/archive/weewx.sdb</span>.
|
|
As the Davis VantagePro can store a couple thousand archive records internally,
|
|
this could take a minute or two. I've found this process particularly slow on
|
|
SuSE for some reason.</p>
|
|
<p><span class="code">Weewx</span> will then start monitoring LOOP data, printing
|
|
a short version of the received data on standard output, about once every two
|
|
seconds.</p>
|
|
<p>You can tell a running instance of <span class="code">weewx</span> to reread
|
|
its configuration file by sending it the <span class="code">HUP</span> signal.
|
|
First run <span class="code">ps</span> to find out the Process ID (PID) number
|
|
of the instance, then send it the <span class="code">HUP</span> signal:</p>
|
|
<p class="tty">ps -a # Note
|
|
the PID of the weewxd.py process</p>
|
|
<p class="tty">kill -HUP <em>pid</em> # Send it a HUP signal</p>
|
|
<h2><a name="Running_as_a_daemon">Running as a daemon</a></h2>
|
|
<p>For unattended operations it is best to have <span class="code">weewx</span>
|
|
run as a daemon, started automatically when the server is rebooted. Start by
|
|
selecting the appropriate run script. They can be found under
|
|
<span class="code"><em>$WEEWX_ROOT</em>/start_script</span>. </p>
|
|
<table align="center" style="width: 70%">
|
|
<tr>
|
|
<td style="width: 25%">SuSE:</td>
|
|
<td class="code"><em>$WEEWX_ROOT</em>/start_script/SuSE/weewx</td>
|
|
</tr>
|
|
<tr>
|
|
<td style="width: 25%">Debian/Ubuntu:</td>
|
|
<td class="code"><em>$WEEWX_ROOT</em>/start_script/Debian/weewx</td>
|
|
</tr>
|
|
</table>
|
|
<p>Check the chosen script to make sure the variable <span class="code">WEEWX_ROOT</span>
|
|
inside has been set to the proper root directory for your <span class="code">
|
|
weewx</span> installation (it should have been set to the correct value automatically
|
|
by the install process, but it's worth checking). </p>
|
|
<p>Copy it to the proper location for your system:</p>
|
|
<table align="center" style="width: 70%">
|
|
<tr>
|
|
<td style="width: 25%">SuSE:</td>
|
|
<td class="code">cp <em>$WEEWX_ROOT</em>/start_script/SuSE/weewx /etc/init.d</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Debian/Ubuntu:</td>
|
|
<td class="code">cp <em>$WEEWX_ROOT</em>/start_script/Debian/weewx /etc/init.d</td>
|
|
</tr>
|
|
</table>
|
|
<p>Make sure the script is executable:</p>
|
|
<table align="center" style="width: 70%">
|
|
<tr>
|
|
<td style="width: 25%">SuSE:</td>
|
|
<td class="code">chmod +x /etc/init.d/weewx</td>
|
|
</tr>
|
|
<tr>
|
|
<td style="width: 25%">Debian/Ubuntu:</td>
|
|
<td class="code">chmod +x /etc/init.d/weewx</td>
|
|
</tr>
|
|
</table>
|
|
<p>Create symbolic links in the run level directories:</p>
|
|
<table align="center" style="width: 70%">
|
|
<tr>
|
|
<td style="width: 25%">SuSE:</td>
|
|
<td class="code">/usr/lib/lsb/install_initd /etc/init.d/weewx</td>
|
|
</tr>
|
|
<tr>
|
|
<td style="width: 25%">Debian/Ubuntu:</td>
|
|
<td class="code">update-rc.d weewx defaults 98</td>
|
|
</tr>
|
|
</table>
|
|
<p><span class="code">Weewx</span> will now start automatically whenever your
|
|
system is booted. You can also manually start, stop, and restart the
|
|
<span class="code">weewx</span> daemon:</p>
|
|
<p class="tty">/etc/init.d/weewx start</p>
|
|
<p class="tty">/etc/init.d/weewx stop</p>
|
|
<p class="tty">/etc/init.d/weewx restart</p>
|
|
<p>By default, the scripts are designed to have <span class="code">weewx</span>
|
|
run at run levels 2, 3, 4 and 5. Incidentally, a nice tool for setting run levels
|
|
with Debian (Ubuntu) systems is
|
|
<a href="http://sysv-rc-conf.sourceforge.net/">sysv-rc-conf</a>. It uses a curses
|
|
interface to allow you to change easily which run level any of your daemons
|
|
runs at. There is a similar tool on SuSE. From the start menu run the YAST Control
|
|
Center, then look for Systems Services (Runlevel). Pick "Expert" mode to see
|
|
the run levels.</p>
|
|
<p>You can also tell <span class="code">weewx</span> to reread its configuration
|
|
file without stopping by using the 'reload' option:</p>
|
|
<p class="tty">/etc/init.d/weewx reload</p>
|
|
<h1><a name="Compatibility_with_wview">Compatibility with <span class="code">
|
|
wview</span></a></h1>
|
|
<p>The sqlite3 archive database used by <span class="code">weewx</span> (nominally,
|
|
<span class="code">weewx.sdb</span>) is completely compatible with the database
|
|
used by <a href="http://www.wviewweather.com">wview</a> (usually called
|
|
<span class="code">wview-archive.sdb</span>), at least as of wview Version 5.2.X.
|
|
The schema and its semantics is identical. However, the statistical file
|
|
<span class="code">stats.sdb</span> is different, and must be rebuilt. This
|
|
will be done automatically on startup by <span class="code">weewx</span>.</p>
|
|
<h1><a name="Monitoring_weewx">Monitoring <span class="code">weewx</span></a></h1>
|
|
<p><span class="code">Weewx</span> logs many events to the system log. On Debian
|
|
systems, this is <span class="code">/var/log/syslog</span>, on SuSE,
|
|
<span class="code">/var/log/messages</span>. Your system may use yet another
|
|
place. When troubleshooting the system, be sure to check it!</p>
|
|
<p>Setting the option <span class="code">debug </span>in <span class="code">
|
|
weewx.conf</span> to <span class="code">1</span> (one) will generate many more
|
|
checks and output and can be useful for debugging.</p>
|
|
<h1> <a name="Troubleshooting">Troubleshooting</a></h1>
|
|
<p>If you get stuck, be sure to </p>
|
|
<ul>
|
|
<li>Set option <span class="code">debug </span>in <span class="code">weewx.conf</span>
|
|
to <span class="code">1</span> (one)! It will put lots more information
|
|
in the log file, which can be very useful for troubleshooting and debugging!</li>
|
|
<li><a href="#Monitoring_weewx">Look at the log file</a>. I am always happy
|
|
to take questions, but the first thing I will ask you is: "Did you look
|
|
at the log file?"</li>
|
|
<li>Run from the command line. Generally, weewx will catch and log any unrecoverable
|
|
exceptions. But if you are getting strange results, it is worth running
|
|
from the command line and looking for any clues.</li>
|
|
</ul>
|
|
<h2> Execution</h2>
|
|
<h3><span class="code">configobj</span> errors</h3>
|
|
<p>These are errors in the configuration file. Two are very common. Incidentally,
|
|
these errors are far easier to diagnose when <span class="code">weewx</span>
|
|
is run from the command line.</p>
|
|
<h4><span class="code">configobj.DuplicateError</span> exception</h4>
|
|
<p>This error is caused by using an identifier more than once in the configuration
|
|
file. For example, you may have inadvertently listed your FTP server twice:</p>
|
|
<pre>[Reports]
|
|
[[FTP]]
|
|
... (details elided)
|
|
user = fred
|
|
server = ftp.myhost.com
|
|
password = mypassword
|
|
server = ftp.myhost.com # OOPS! Listed it twice!
|
|
path = /weather
|
|
... </pre>
|
|
<p>Generally, if you encounter this error, the log file will give you the line
|
|
number it happened in:</p>
|
|
<pre>Apr 24 12:09:15 raven weewx[11480]: wxengine: Error while parsing configuration file /home/weewx/weewx.conf
|
|
Apr 24 12:09:15 raven weewx[11480]: wxengine: Unable to initialize main loop:
|
|
Apr 24 12:09:15 raven weewx[11480]: **** Duplicate keyword name at line 254.
|
|
Apr 24 12:09:15 raven weewx[11480]: **** Exiting. </pre>
|
|
<h4><span class="code">configobj.NestingError</span> exception</h4>
|
|
<p>This is a very similar error, and is caused by a misformed section nesting.
|
|
For example:</p>
|
|
<pre>[Reports]
|
|
[[FTP]]]
|
|
... (details elided)</pre>
|
|
<p>Note the extra closing bracket on the subsection <span class="code">FTP</span>.</p>
|
|
<h2>Hardware</h2>
|
|
<h3>Tips on a reliable system</h3>
|
|
<p>If you are having problems keeping your weather station up for long periods
|
|
of time, here are some tips, in decreasing order of importance:</p>
|
|
<ul>
|
|
<li>Run on dedicated hardware. If you are using the server for other tasks,
|
|
particularly as your desktop machine, you will have reliability problems.
|
|
If you are using it as a print or network server, you will probably be OK.</li>
|
|
<li>Run headless. Modern graphical systems are extremely complex. As new
|
|
features are added, test suites don't always catch up. Your system will
|
|
be much more reliable if you run it without a windowing system (X Windows,
|
|
in the case of Linux).</li>
|
|
<li>Use an Uninterruptible Power Supply (UPS). The vast majority of power
|
|
glitches are very short lived — just a second or two — so you do not need
|
|
a big one. The 425 VA unit I use to protect my fit-PC cost me $55 at Best
|
|
Buy.</li>
|
|
<li>Use a VantagePro console with a serial connection, not a USB connection.
|
|
See the next section for details.</li>
|
|
<li>If you do use a USB connection, put a ferrite coil on each end of the
|
|
connection.</li>
|
|
</ul>
|
|
<h3>cp2101 converter problems</h3>
|
|
<p>The USB converter used in the Davis VantagePro is known to have some "noise"
|
|
problems. The symptom is that the Linux kernel will disconnect from your old
|
|
USB port claiming "EMI noise", and reconnect to a new and different port, where
|
|
<span class="code">weewx</span> can't find it. Here's a typical log output:</p>
|
|
<pre>Nov 29 10:40:21 hummingbird kernel: [6661624.786792] hub 2-0:1.0: port 3 disabled by hub (EMI?), re-enabling...
|
|
Nov 29 10:40:21 hummingbird kernel: [6661624.786871] usb 2-3: USB disconnect, address 2
|
|
Nov 29 10:40:21 hummingbird kernel: [6661624.795778] cp2101 2-3:1.0: device disconnected
|
|
Nov 29 10:40:21 hummingbird weewx[25808]: VantagePro: Max retries exceeded while getting LOOP packets</pre>
|
|
<pre> </pre>
|
|
<pre>... (messages elided)</pre>
|
|
<pre> </pre>
|
|
<pre>Nov 29 10:40:22 hummingbird kernel: [6661625.352340] cp2101 2-3:1.0: cp2101 converter detected
|
|
Nov 29 10:40:22 hummingbird kernel: [6661625.528107] usb 2-3: reset full speed USB device using ohci_hcd and address 3
|
|
Nov 29 10:40:22 hummingbird kernel: [6661625.735497] usb 2-3: cp2101 converter now attached to ttyUSB1</pre>
|
|
<p>In this example, the VantagePro was connected to <span class="code">/dev/ttyUSB0</span>,
|
|
but then reconnected to <span class="code">/dev/ttyUSB1</span>. </p>
|
|
<p>If you put ferrite coils on the USB connection, you will eliminate 90% of
|
|
this problem. I did this about 6 months ago, and have not had a problem since.
|
|
</p>
|
|
<p>However, there is one final step you can take that will reallly harden up
|
|
your system: install a <span class="code">udev</span> script that will create
|
|
a symbolic link to the VantagePro USB port, whatever it might be. With this
|
|
approach, if the port jumps from <span class="code">ttyUSB0</span> to
|
|
<span class="code">ttyUSB1</span>, the symbolic link will move as well. You
|
|
just specify port <span class="code">/dev/vpro</span> and be done with it. Here's
|
|
how:</p>
|
|
<h4>Installing a udev script</h4>
|
|
<p>I have installed a file <span class="code">/etc/udev/rules.d/66-vpro.rules</span>
|
|
on my fit-PC that looks like this:</p>
|
|
<pre># Automount the VantagePro2 to port /dev/vpro.</pre>
|
|
<pre># Install in /etc/udev/rules.d/66-vpro.rules</pre>
|
|
<pre>#</pre>
|
|
<pre>ACTION=="add", ATTRS{interface}=="CP2102 USB to UART Bridge Controller", SYMLINK+="vpro"</pre>
|
|
<p>What this rule says is that when the USB port is plugged in (action
|
|
<span class="code">add</span>), and it has an attribute with name
|
|
<span class="code">interface</span> that is equal to "<span class="code">CP2102
|
|
USB to UART Bridge Controller</span>", then add a symbolic link for its physical
|
|
port to <span class="code">/dev/vpro</span>. </p>
|
|
<p>Your controller may have a different identifier!! I can recommend this article,
|
|
"<a href="http://www.reactivated.net/writing_udev_rules.html"><em>Writing udev
|
|
rules</em></a>," for how to find and write an appropriate
|
|
<span class="code">udev</span> rule for your controller. (Note, however, that
|
|
this article uses the old <span class="code">udevinfo</span> command, rather
|
|
than the newer <span class="code">udevadm</span> command.) In particular, run
|
|
the command</p>
|
|
<pre># udevadm info --attribute-walk --path $(udevadm info --query=path --name=/dev/ttyUSB0) </pre>
|
|
<p>where<span class="code"> /dev/ttyUSB0</span> is the port (substitute your
|
|
real USB port) the VP2 is attached to. It will print out various identifiers
|
|
that can be useful in identifying your VP2 to <span class="code">udev</span>.
|
|
While the example script above used a rule that matched attribute
|
|
<span class="code">interface</span>, others are possible. For example, you might
|
|
chose to match the attribute <span class="code">product</span>.</p>
|
|
<p>Once you've installed your <span class="code">udev</span> rule, you can then
|
|
set <span class="code">port=/dev/vpro</span> in <span class="code">weewx.conf</span>,
|
|
confident that it will always point to your VantagePro2, no matter which USB
|
|
port it is actually attached to!</p>
|
|
<p>I have tested this system many times. You can yank the USB port out of the
|
|
machine and then plug it back in while also pulling out the network connection
|
|
in the middle of an FTP upload: weewx will recover.</p>
|
|
<p>Or, at least, it should!</p>
|
|
<h2> Templates</h2>
|
|
<h3><span class="code">Cheetah.NameMapper.NotFound</span> errors</h3>
|
|
<p>If you get errors of the sort:</p>
|
|
<pre>Apr 12 05:12:32 raven reportengine[3074]: filegenerator: Caught exception "<class 'NameMapper.NotFound'>"
|
|
Apr 12 05:12:32 raven reportengine[3074]: **** Message: "cannot find 'fubar' in template /home/weewx/skins/Standard/index.html.tmpl"
|
|
Apr 12 05:12:32 raven reportengine[3074]: **** Ignoring template and continuing.</pre>
|
|
<p>you have a tag in your template that <span class="code">weewx</span> does
|
|
not recognize (in this example, it's the tag <span class="code">$fubar</span>
|
|
in the template <span class="code">/home/weewx/skins/Standard/index.html.tmpl</span>.</p>
|
|
<h1> A<a name="Architectural_notes">rchitectural notes</a></h1>
|
|
<p>This section is not needed to get started. </p>
|
|
<h2>Goals</h2>
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<p>The primary goals of <span class="code">weewx </span>are:</p>
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<ul>
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<li>Architectural simplicity. No semaphores, no named pipes, no inter-process
|
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communications, no complex multi-threading to manage. </li>
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<li>"Fast enough." In any design decision, architectural simplicity and
|
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elegance trumps speed. </li>
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<li>One code base. The same code base should be used for all platforms,
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all weather stations, all reports, and any combination of features. Ample
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configuration and customization options should be provided so the user doesn't
|
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feel tempted to start hacking code. At worse, the user may have to subclass,
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which is much easier to port to newer versions of the code base, than customizing
|
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the base code.</li>
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<li>Minimal reliance on external packages, so the user doesn't have to go
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chase them down all over the Web before getting started.</li>
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<li>Support only the Davis VantagePro2 initially (that's what I have), but
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make no architectural decisions that lock out other stations.</li>
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<li>As "pythonic" as I know how to make it. I'm a beginner Python programmer
|
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with two decades of experience in C++. I tried hard to not make the code
|
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base look like it was written by a C++ programmer who stumbled across a
|
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Python manual!</li>
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</ul>
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<h2>Strategies</h2>
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<p>To meet these goals, the following strategies were used:</p>
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<ul>
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<li>A "micro-kernel" design. The actual internal engine does very little.
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It's main job is to load and run <em>services</em> at runtime, making it
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easy for users to add or subtract features.</li>
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<li>A largely stateless design style. For example, many of the processing
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routines read their own data from the database, rather than caching it and
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sharing with other processing routines. While this means the same data may
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be read multiple times, it also means the only point of possible cache incoherence
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is through the database, where transactions are easily controlled. This
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|
greatly reduces the chances of corrupting the data, making it much easier
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|
to understand and modify the code base.</li>
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<li>Isolate the data collection and archiving code in a single thread that
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is simple enough that it is unlikely to crash. The report processing is
|
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where most mistakes are likely to happen, so isolate that in a separate
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thread. If it crashes, it will not affect the main data thread.</li>
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<li>A powerful configuration parser,
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<a href="http://www.voidspace.org.uk/python/configobj.html">ConfigObj</a>,
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by Michael Foord and Nicola Larosa, was chosen to read the configuration
|
|
file. This allows many options that might otherwise have to go in the code
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|
to go instead in a configuration file.</li>
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<li>A powerful templating engine,
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<a href="http://www.cheetahtemplate.org/">Cheetah</a>, was used. This allows
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many variables that I may not have thought of to be accessed from within
|
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the HTML templates, without starting to modify the code.</li>
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<li>Pure Python. The code base is 100% Python — no underlying C libraries
|
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need be built to install <span class="code">weewx</span>. This also means
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no Makefiles are needed.</li>
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</ul>
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<p>While <span class="code">weewx </span>is nowhere near as fast at generating
|
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images and HTML as its predecessor, <span class="code">wview </span>(this is
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|
partially because it uses fancier fonts and a much more powerful templating
|
|
engine), it is 'fast enough' for all platforms but the slowest. I run it regularly
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on a 500 MHz machine where generating the 9 images used in the "Current Conditions"
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page takes just under 2 seconds (compared with <span class="code">wview</span>'s
|
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0.4 seconds). </p>
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<p>Unfortunately, the architectural goal of one code base is likely to be broken
|
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with the arrival of Python V3.X. It has so many changes that are not backwards
|
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compatible with V2.X, that a separate code base will most likely be needed.
|
|
My intention is to stick with the V2.5 and V2.6 versions until V3.X is so widespread
|
|
it cannot be ignored, then make a permanent switch. I doubt this will affect
|
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the average <span class="code">weewx</span> user. </p>
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<p>All writes to the databases are protected by transactions. You can kill the
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program at any time (either Control-C if run from the command line or "<span class="code">/etc/init.d/weewx
|
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stop</span>" if a daemon) without fear of corrupting the databases.</p>
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<p>The code makes ample use of exceptions to insure graceful recovery from problems
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such as network outages. It also monitors socket and console timeouts, restarting
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whatever it was working on several times before giving up. In the case of an
|
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unrecoverable console error (such as the console not responding at all), the
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program waits 60 seconds then restarts the program from the top.</p>
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<p>Any "hard" exceptions, that is those that do not involve network and console
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timeouts and are most likely due to a logic error, are logged, reraised, and
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ultimately cause thread termination. If this happens in the main thread (not
|
|
likely due to its simplicity), then this causes program termination. If it happens
|
|
in the report processing thread (much more likely), then only the generation
|
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of reports will be affected — the main thread will continue downloading data
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off the instrument and putting them in the database. You can fix the problem
|
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at your leisure, without worrying about losing any data.</p>
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<h2>Terminology</h2>
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<p>This is a glossary of terminology used throughout the code.</p>
|
|
<table style="width: 100%">
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<tr>
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<td>packet</td>
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<td>Something obtained off the weather station. Frequently uses a complex
|
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internal encoding, so it requires some processing to be useful.</td>
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</tr>
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<tr>
|
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<td>record</td>
|
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<td>Something obtained off the SQL database. </td>
|
|
</tr>
|
|
<tr>
|
|
<td>archive packet</td>
|
|
<td>A packet obtained off the store on the weather station. For example,
|
|
with a Davis VantagePro, it's obtained using their
|
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<span class="code">DMPAFT</span> command. </td>
|
|
</tr>
|
|
<tr>
|
|
<td>loop packet</td>
|
|
<td>A packet with the current observations. For example, with a Davis
|
|
VantagePro, it's obtained using their <span class="code">LOOP</span>
|
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command. </td>
|
|
</tr>
|
|
<tr>
|
|
<td>archive record</td>
|
|
<td>A record obtained off the SQL database</td>
|
|
</tr>
|
|
<tr>
|
|
<td>tuple-time</td>
|
|
<td>An instance of the Python object <span class="code">time.struct_time</span>.
|
|
This is a 9-wise tuple that represent a time. It could be in either
|
|
local time or UTC, though usually the former. See module
|
|
<span class="code">time</span> for more information. They are useful
|
|
because they are a little closer in format to what the Davis VantagePro
|
|
uses, although they still require a bit of processing. Variables carrying
|
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tuple time usually have a suffix '<span class="code">_tt</span>'.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>epoch time</td>
|
|
<td>Sometimes referred to as "unix time," or "unix epoch time." The
|
|
number of seconds since the epoch, which is 1 Jan 1970 00:00:00 UTC.
|
|
Hence, it always represents UTC (well.... after adding a few leap seconds.
|
|
But, close enough). This is the time used on the sqlite archive and
|
|
appears as type '<span class="code">dateTime</span>' in the SQL schema,
|
|
perhaps an unfortunate name because of the similarity to the Python
|
|
type '<span class="code">datetime</span>'. Very easy to manipulate, but it's an opaque big number.
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td>time stamp</td>
|
|
<td>A variable in unix epoch time. Always in UTC. Variables carrying
|
|
a time stamp usually have a suffix '<span class="code">_ts</span>'.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>datetime</td>
|
|
<td>An instance of the Python object <span class="code">datetime.datetime</span>.
|
|
Variables of type datetime usually have a suffix '<span class="code">_dt</span>'.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>SQL type</td>
|
|
<td>A type that appears in the SQL database. This usually looks something
|
|
like '<span class="code">outTemp</span>', '<span class="code">barometer</span>',
|
|
'<span class="code">extraTemp1</span>', and so on.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>observation type</td>
|
|
<td>A type that can be used in the presentations. This is generally
|
|
all of the SQL types, plus calculated data (such as
|
|
<span class="code">rms</span> or <span class="code">vecavg</span>).</td>
|
|
</tr>
|
|
<tr>
|
|
<td>value tuple</td>
|
|
<td>A 3-way tuple. First element is a value, second element the unit
|
|
type the value is in, the third the unit group. An example would be
|
|
<span class="code">(21.2, 'degree_C', 'group_temperature')</span>.</td>
|
|
</tr>
|
|
</table>
|
|
<h2> Units</h2>
|
|
<p>In general, there are three different areas where the unit system makes a
|
|
difference.: </p>
|
|
<ol>
|
|
<li>On the weather station. As far as I know, the Davis VantagePro series
|
|
supports only U.S. Customary units internally. </li>
|
|
<li>In the database. The unit system of any individual record is indicated
|
|
by the "<span class="code">usUnits</span>" field. The numerical value 1
|
|
indicates U.S. Customary, 2 indicates Metric. </li>
|
|
<li>In the presentation (i.e., html and image files). </li>
|
|
</ol>
|
|
<p>The general strategy is that measurements are stored internally in the native
|
|
measurement system of the weather instrument. That is, the units used in #1
|
|
and #2 are always the same. With Version 1.5, weewx supports translations between
|
|
#2 and #3, allowing any unit system to be used in the presentation layer.</p>
|
|
<p>It would be easy enough to support an instrument that uses metric units internally,
|
|
although this has not been done yet. </p>
|
|
<h2>Value "<span class="code">None</span>"</h2>
|
|
<p>The Python special value '<span class="code">None</span>' is used throughout
|
|
to signal a missing data point. All functions expect it.</p>
|
|
<p>However, the time value must never be '<span class="code">None</span>'. This
|
|
is because it is used as the primary key in the SQL database. </p>
|
|
<h2>Time</h2>
|
|
<p><span class="code">Weewx </span>stores all data in UTC (roughly, "Greenwich"
|
|
or "Zulu") time. However, usually one is interested in weather events in local
|
|
time and want image and HTML generation to reflect that. Furthermore, most weather
|
|
stations are configured in local time. This requires that many data times be
|
|
converted back and forth between UTC and local time. To avoid tripping up over
|
|
time zones and daylight savings time, <span class="code">weewx</span> generally
|
|
uses Python routines to do this conversion. Nowhere in the code base is there
|
|
any explicit recognition of DST. Instead, its presence is implicit in the conversions.
|
|
At times, this can cause the code to be relatively inefficient. </p>
|
|
<p>For example, if one wanted to plot something every 3 hours in UTC time, it
|
|
would be very simple: to get the next plot point, just add 10,800 to the epoch
|
|
time:</p>
|
|
<p class="tty">next_ts = last_ts + 10800</p>
|
|
<p>But, if one wanted to plot something for every 3 hours <em>in local time</em>
|
|
(that is, at 0000, 0300, 0600, etc.), despite a possible DST change in the middle,
|
|
one could modify the above to recognize whether a DST transition occurs sometime
|
|
between <span class="code">last_ts</span> and the next three hours and, if so,
|
|
make the necessary adjustments. This is generally what <span class="code">wview</span>
|
|
does. <span class="code">Weewx </span>takes a different approach and converts
|
|
from UTC to local, does the arithmetic, then converts back. This is inefficient,
|
|
but bulletproof against changes in DST algorithms, etc:</p>
|
|
<p class="tty">time_dt = datetime.datetime.fromtimestamp(last_ts)</p>
|
|
<p class="tty">delta = datetime.timedelta(seconds=10800)</p>
|
|
<p class="tty">next_dt = time_dt + delta</p>
|
|
<p class="tty">next_ts = int(time.mktime(next_dt.timetuple()))</p>
|
|
<p>Other time conversion problems are handled in a similar manner.</p>
|
|
</div>
|
|
|
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</body>
|
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</html>
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