Coverage for pyguymer3/geo/calc_angle_between_two_locs.py: 100%

1#!/usr/bin/env python3 

2 

3# Define function ... 

4def calc_angle_between_two_locs( 

5 lon1_deg, 

6 lat1_deg, 

7 lon2_deg, 

8 lat2_deg, 

9 /, 

10): 

11 """Calculate the angle between two coordinates. 

12 

13 This function reads in two coordinates (in degrees) on the surface of a 

14 sphere and calculates the angle (in degrees) between them, as viewed from 

15 the centre of the sphere. 

16 

17 Parameters 

18 ---------- 

19 lon1_deg : float 

20 the longitude of the first coordinate (in degrees) 

21 lat1_deg : float 

22 the latitude of the first coordinate (in degrees) 

23 lon2_deg : float 

24 the longitude of the second coordinate (in degrees) 

25 lat2_deg : float 

26 the latitude of the second coordinate (in degrees) 

27 

28 Returns 

29 ------- 

30 angle : float 

31 the angle between the two coordinates (in degrees) 

32 

33 Notes 

34 ----- 

35 Copyright 2017 Thomas Guymer [1]_ 

36 

37 References 

38 ---------- 

39 .. [1] PyGuymer3, https://github.com/Guymer/PyGuymer3 

40 """ 

41 

42 # Import standard modules ... 

43 import math 

44 

45 # ************************************************************************** 

46 

47 # Convert to radians ... 

48 lon1_rad = math.radians(lon1_deg) # [rad] 

49 lat1_rad = math.radians(lat1_deg) # [rad] 

50 lon2_rad = math.radians(lon2_deg) # [rad] 

51 lat2_rad = math.radians(lat2_deg) # [rad] 

52 

53 # Calculate angle in radians ... 

54 distance_rad = 2.0 * math.asin( 

55 math.hypot( 

56 math.sin((lat1_rad - lat2_rad) / 2.0), 

57 math.cos(lat1_rad) * math.cos(lat2_rad) * math.sin((lon1_rad - lon2_rad) / 2.0) 

58 ) 

59 ) # [rad] 

60 

61 # Return angle ... 

62 return math.degrees(distance_rad)