35 lines
1.6 KiB
Python
35 lines
1.6 KiB
Python
def calculate_from_bearing(frm, to):
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"""Calculate inital bearing from one coordinate to next (two tuples of coordinates(lat/lng) in degrees in, returns single bearing)"""
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#https://gis.stackexchange.com/questions/228656/finding-compass-direction-between-two-distant-gps-points
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from math import atan2, cos, radians, sin, degrees
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frm = (radians(frm[0]), radians(frm[1]))
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to = (radians(to[0]), radians(to[1]))
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y = sin(to[1]- frm[1]) * cos(to[0])
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x = cos(frm[0]) * sin(to[0]) - sin(frm[0]) * cos(to[0]) * cos(to[1]-frm[1])
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from_bearing = degrees(atan2(y, x))
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if from_bearing < 0:
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from_bearing += 360
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return from_bearing
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def calculate_cardinal(d):
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"""Finds cardinal direction from bearing degree"""
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dirs = ['N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE', 'S', 'SSW', 'SW', 'WSW', 'W', 'WNW', 'NW', 'NNW']
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ix = int(round(d / (360. / len(dirs))))
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card = dirs[ix % len(dirs)]
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return card
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def calculate_deg_change(new_heading, original_heading):
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"""Calculates change between two headings, returns negative degree if change is left, positive if right"""
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normal = abs(original_heading-new_heading)
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across_inital = 360 - abs(original_heading-new_heading)
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if across_inital < normal:
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direction = "left" if original_heading < new_heading else "right"
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track_change = across_inital
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else:
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direction = "right" if original_heading < new_heading else "left"
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track_change = normal
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if direction == "left":
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track_change *= -1
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track_change = round(track_change, 2)
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print(f"Track change of {track_change}° which is {direction}")
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return track_change
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