Coverage for pyguymer3/geo/_add_vertical_gridlines.py: 6%

1#!/usr/bin/env python3 

2 

3# Define function ... 

4def _add_vertical_gridlines( 

5 ax, 

6 /, 

7 *, 

8 color = "black", 

9 linestyle = ":", 

10 linewidth = 0.5, 

11 locs = None, 

12 ngrid = -1, 

13 npoint = 181, 

14 zorder = 2.0, 

15): 

16 """Add vertical gridlines to a Cartopy axis. 

17 

18 Parameters 

19 ---------- 

20 ax : cartopy.mpl.geoaxes.GeoAxesSubplot 

21 the axis to add the gridlines to 

22 color : str, optional 

23 the colour of the gridlines 

24 linestyle : str, optional 

25 the style of the gridlines 

26 linewidth : float, optional 

27 the width of the gridlines 

28 locs : list of float, optional 

29 the locations of the gridlines (in degrees) 

30 ngrid : int, optional 

31 the number of gridlines to draw 

32 npoint : int, optional 

33 the number of points along each gridline to draw 

34 zorder : float, optional 

35 the zorder to draw the gridlines with (the default value has been chosen 

36 to match the value that it ends up being if the gridlines are not drawn 

37 with the zorder keyword specified -- obtained by manual inspection on 

38 5/Dec/2023) 

39 

40 Notes 

41 ----- 

42 If ``ngrid`` is more than "1" then it is used to create the gridline 

43 locations. If it is not, then the gridline locations will attempt to be made 

44 from ``locs`` instead. 

45 

46 Copyright 2017 Thomas Guymer [1]_ 

47 

48 References 

49 ---------- 

50 .. [1] PyGuymer3, https://github.com/Guymer/PyGuymer3 

51 """ 

52 

53 # Import standard modules ... 

54 import os 

55 

56 # Import special modules ... 

57 try: 

58 import cartopy 

59 cartopy.config.update( 

60 { 

61 "cache_dir" : os.path.expanduser("~/.local/share/cartopy_cache"), 

62 } 

63 ) 

64 except: 

65 raise Exception("\"cartopy\" is not installed; run \"pip install --user Cartopy\"") from None 

66 try: 

67 import numpy 

68 except: 

69 raise Exception("\"numpy\" is not installed; run \"pip install --user numpy\"") from None 

70 

71 # ************************************************************************** 

72 

73 # Determine x-locations depending on inputs ... 

74 if ngrid > 1: 

75 xlocs = numpy.linspace(-180.0, +180.0, num = ngrid) # [°] 

76 elif locs is not None: 

77 xlocs = numpy.array(locs) # [°] 

78 else: 

79 raise Exception("\"ngrid > 1\" is not True and \"locs is not None\" is not True") from None 

80 

81 # Loop over x-locations ... 

82 for xloc in xlocs: 

83 # Add gridline to axis ... 

84 ax.plot( 

85 xloc * numpy.ones(npoint), 

86 numpy.linspace(-90.0, +90.0, num = npoint), 

87 color = color, 

88 linestyle = linestyle, 

89 linewidth = linewidth, 

90 transform = cartopy.crs.PlateCarree(), 

91 zorder = zorder, 

92 )