mirror of
https://github.com/TheAlgorithms/Python.git
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Akhil Devarasetty
167c924ab9
* feat: implement shoelace formula for polygon area calculation * feat: add initial bearing calculation function between geographic points
79 lines
2.2 KiB
Python
79 lines
2.2 KiB
Python
"""
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Initial bearing (forward azimuth) between two geographic points.
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Points are (latitude, longitude) in decimal degrees. Returns bearing in degrees
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clockwise from true north in the range [0, 360).
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Reference: https://en.wikipedia.org/wiki/Bearing_(navigation)
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"""
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from __future__ import annotations
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import math
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def initial_bearing(
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origin: tuple[float, float], destination: tuple[float, float]
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) -> float:
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"""
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Compute the initial bearing from `origin` to `destination`.
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Parameters
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----------
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origin, destination : tuple[float, float]
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(latitude, longitude) in decimal degrees.
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Returns
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-------
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float
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Initial bearing in degrees, clockwise from north in [0, 360).
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Raises
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------
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TypeError
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If inputs are not 2-tuples of numbers.
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ValueError
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If the two points are identical (bearing undefined).
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Examples
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>>> round(initial_bearing((50.066389, -5.714722), (58.643889, -3.07)), 3)
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9.12
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>>> round(initial_bearing((0.0, 0.0), (1.0, 1.0)), 3)
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44.996
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>>> initial_bearing((0.0, 0.0), (0.0, 0.0))
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Traceback (most recent call last):
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...
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ValueError: origin and destination are the same point; bearing is undefined
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"""
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try:
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lat1, lon1 = float(origin[0]), float(origin[1])
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lat2, lon2 = float(destination[0]), float(destination[1])
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except Exception as exc:
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raise TypeError(
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"origin and destination must be 2-tuples of numeric values"
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) from exc
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if lat1 == lat2 and lon1 == lon2:
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raise ValueError(
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"origin and destination are the same point; bearing is undefined"
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)
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# convert degrees to radians
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phi1 = math.radians(lat1)
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phi2 = math.radians(lat2)
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delta_lambda = math.radians(lon2 - lon1)
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x = math.sin(delta_lambda) * math.cos(phi2)
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y = math.cos(phi1) * math.sin(phi2) - math.sin(phi1) * math.cos(phi2) * math.cos(
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delta_lambda
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)
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theta = math.atan2(x, y) # result in radians relative to north
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bearing = (math.degrees(theta) + 360.0) % 360.0
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return bearing
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if __name__ == "__main__":
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# simple demonstration
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print(initial_bearing((50.066389, -5.714722), (58.643889, -3.07)))
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