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Merge branch 'glennmckechnie-glennmckechnie-patch-1'

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Tom Keffer
2018-03-06 03:46:16 -08:00
parent f06e2292a5 378d7b83c8
commit efb5a9725f
1 changed files with 32 additions and 10 deletions
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docs/customizing.htm
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@@ -1241,7 +1241,6 @@ $month.outTemp.max</pre>
<td>Example</td>
<td>Meaning</td>
</tr>
</tbody>
<tr>
<td class="first_col code">$hour($hours_ago=<i>h</i>)
</td>
@@ -1273,6 +1272,7 @@ $month.outTemp.max</pre>
<td class="code">$year($years_ago=1).outTemp.max</td>
<td>The maximum temperature last year.</td>
</tr>
</tbody>
</table>
<h3 id="unit_conversion_options">Unit conversion options</h3>
@@ -6053,13 +6053,26 @@ mysql&gt;<span class="cmd"> RENAME TABLE weewx_new.archive TO weewx.archive;</sp
the unit group <span class='code'>group_energy</span> (which
already exists), so it can enjoy the labels and formats
already provided for this group. This is done by extending the dictionary <span
class='code'>weewx.units.obs_group_dict</span>, typically by
adding Python code to the file <span class='code'>user/extensions.py</span>:
</p>
<pre class='tty'>import weewx.units
weewx.units.obs_group_dict['electricity'] = 'group_energy'</pre>
class='code'>weewx.units.obs_group_dict</span>.</p>
<p>Once the observation has been associated with a unit group,
<p>Add the following to our new services file
<span class='code'>user/electricity.py</span>, just after the last
import statement:</p>
<pre class="tty">import weewx
from weewx.engine import StdService
<span class="highlight">
import weewx.units
weewx.units.obs_group_dict['electricity'] = 'group_energy'</span>
class AddElectricity(StdService):
# [...]</pre>
<p>When our new service gets loaded by the WeeWX engine, these few lines
will get run. They tell WeeWX that our new observation type,
<span class='code'>electricity</span>, is part of the unit group
<span class='code'>group_energy</span>.
Once the observation has been associated with a unit group,
the unit labels and other tag syntax will work for that
observation. So, now a tag like:</p>
<pre class='tty'>$month.electricity.sum</pre>
@@ -6069,7 +6082,7 @@ weewx.units.obs_group_dict['electricity'] = 'group_energy'</pre>
<h2>Creating a new unit group</h2>
<p>
That was an easy one, because there was already an existing
group, <span class='code'>group_amp</span>, that covered our new
group, <span class='code'>group_energy</span>, that covered our new
observation type. But, what if we are measuring something entirely new, like
force with time? There is nothing in the existing system of
units that covers things like newtons or pounds. We will have to
@@ -6078,13 +6091,14 @@ weewx.units.obs_group_dict['electricity'] = 'group_energy'</pre>
</p>
<p>
We assume we have a new observation type, <span class='code'>force</span>,
that we are measuing over time. We will create a new unit group,
that we are measuring over time, for a service named <span class='code'>
user/rocket.py</span>. We will create a new unit group,
<span class='code'>group_force</span>, and new units, <span
class='code'>newton</span> and <span class='code'>pound</span>.
Our new observation, <span class='code'>force</span>, will
belong to <span class='code'>group_force</span>, and will be
measured in units of <span class='code'>newton</span> or <span
class='code'>pound</span>.
class='code'>pound</span>.
</p>
<ol>
<li>As before, we start by specifying what group our new
@@ -6114,6 +6128,14 @@ weewx.units.conversionDict['pound'] = {'newton': lambda x : x * 4.44822}
</li>
</ol>
<p>As with the previous example of <span class='code'>group_energy</span>,
the last step is to extend the <span class='code'>
weewx.units.obs_group_dict</span> dictionary so that these new units can
be used by our service. We do this by adding the Python code from
steps 1 - 4 above into
our new services file <span class='code'>user/rocket.py</span>, at the
head of that file and just after the last import statement (as in the
previous example).</p>
<h2>Use the new types</h2>