forked from vv01f/ccc-map
35 lines
1.1 KiB
Python
Executable File
35 lines
1.1 KiB
Python
Executable File
#!/usr/bin/env python3
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import math
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def arc_to_deg(arc):
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"""convert spherical arc length [m] to great circle distance [deg]"""
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return float(arc)/6371/1000 * 180/math.pi
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def deg_to_arc(deg):
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"""convert great circle distance [deg] to spherical arc length [m]"""
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return float(deg)*6371*1000 * math.pi/180
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def latlon_to_xyz(lat,lon):
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"""Convert angluar to cartesian coordiantes
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latitude is the 90deg - zenith angle in range [-90;90]
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lonitude is the azimuthal angle in range [-180;180]
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"""
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r = 6371 # https://en.wikipedia.org/wiki/Earth_radius
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theta = math.pi/2 - math.radians(lat)
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phi = math.radians(lon)
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x = r * math.sin(theta) * math.cos(phi) # bronstein (3.381a)
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y = r * math.sin(theta) * math.sin(phi)
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z = r * math.cos(theta)
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return [x,y,z]
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def xyz_to_latlon (x,y,z):
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"""Convert cartesian to angular lat/lon coordiantes"""
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r = math.sqrt(x**2 + y**2 + z**2)
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theta = math.asin(z/r) # https://stackoverflow.com/a/1185413/4933053
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phi = math.atan2(y,x)
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lat = math.degrees(theta)
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lon = math.degrees(phi)
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return [lat,lon]
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