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38 lines
1.1 KiB
Python
Executable File
38 lines
1.1 KiB
Python
Executable File
#!/usr/bin/env python3
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import sys
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from astronomy import ObserverGravity
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UsageText = r'''
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USAGE:
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gravity.py latitude height
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Calculates the gravitational acceleration experienced
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by an observer on the surface of the Earth at the specified
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latitude (degrees north of the equator) and height
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(meters above sea level).
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The output is the gravitational acceleration in m/s^2.
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'''
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if __name__ == '__main__':
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if len(sys.argv) != 3:
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print(UsageText)
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sys.exit(1)
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latitude = float(sys.argv[1])
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if latitude < -90.0 or latitude > +90.0:
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print("ERROR: Invalid latitude '{}'. Must be a number between -90 and +90.".format(sys.argv[1]))
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sys.exit(1)
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height = float(sys.argv[2])
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MAX_HEIGHT_METERS = 100000.0
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if height < 0.0 or height > MAX_HEIGHT_METERS:
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print("ERROR: Invalid height '{}'. Must be a number between 0 and {}.".format(sys.argv[1], MAX_HEIGHT_METERS))
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sys.exit(1)
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gravity = ObserverGravity(latitude, height)
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print("latitude = {:8.4f}, height = {:6.0f}, gravity = {:8.6f}".format(latitude, height, gravity))
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sys.exit(0)
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