#!/usr/bin/env python3 # Use the proper idiom in the main module ... # NOTE: See https://docs.python.org/3.12/library/multiprocessing.html#the-spawn-and-forkserver-start-methods if __name__ == "__main__": # This is a test suite for “geo.great_circle()”. # Import standard modules ... import argparse import json import multiprocessing import os import pathlib # Import special modules ... try: import cartopy cartopy.config.update( { "cache_dir" : pathlib.PosixPath("~/.local/share/cartopy_cache").expanduser(), } ) except: raise Exception("\"cartopy\" is not installed; run \"pip install --user Cartopy\"") from None try: import geojson except: raise Exception("\"geojson\" is not installed; run \"pip install --user geojson\"") from None try: import matplotlib matplotlib.rcParams.update( { "backend" : "Agg", # NOTE: See https://matplotlib.org/stable/gallery/user_interfaces/canvasagg.html "figure.dpi" : 300, "figure.figsize" : (9.6, 7.2), # NOTE: See https://github.com/Guymer/misc/blob/main/README.md#matplotlib-figure-sizes "font.size" : 8, } ) import matplotlib.pyplot except: raise Exception("\"matplotlib\" is not installed; run \"pip install --user matplotlib\"") from None try: import numpy except: raise Exception("\"numpy\" is not installed; run \"pip install --user numpy\"") from None # Import my modules ... try: import pyguymer3 import pyguymer3.geo import pyguymer3.image except: raise Exception("\"pyguymer3\" is not installed; run \"pip install --user PyGuymer3\"") from None print(f"Testing \"{pyguymer3.__path__[0]}\" ...") # ************************************************************************** # Create argument parser and parse the arguments ... parser = argparse.ArgumentParser( allow_abbrev = False, description = "Demonstrate the convergence of some great circles.", formatter_class = argparse.ArgumentDefaultsHelpFormatter, ) parser.add_argument( "--absolute-path-to-repository", default = os.path.dirname(os.path.dirname(__file__)), dest = "absPathToRepo", help = "the absolute path to the PyGuymer3 repository", type = str, ) parser.add_argument( "--debug", action = "store_true", help = "print debug messages", ) parser.add_argument( "--dont-make-plots", action = "store_true", dest = "dontMakePlots", help = "don't make the plots (only make the [Geo]JSONs)", ) parser.add_argument( "--eps", default = 1.0e-12, dest = "eps", help = "the tolerance of the Vincenty formula iterations", type = float, ) parser.add_argument( "--number-of-children", default = os.cpu_count(), # TODO: Once I ditch Python 3.11 and # Python 3.12 then I can use # "os.process_cpu_count()" instead. dest = "nChild", help = "the number of child \"multiprocessing\" processes to use when making the tiles", type = int, ) parser.add_argument( "--quiet", action = "store_true", help = "don't print most messages", ) parser.add_argument( "--timeout", default = 60.0, help = "the timeout for any requests/subprocess calls (in seconds)", type = float, ) parser.add_argument( "--tolerance", default = 1.0e-10, dest = "tol", help = "the Euclidean distance that defines two points as being the same (in degrees)", type = float, ) args = parser.parse_args() # ************************************************************************** # Define pairs of coordinates ... coords1 = [ ( -90.0, +15.0), # [°], [°] ( +1.0, +50.7), # [°], [°] (-122.4, +37.6), # [°], [°] ( +91.0, +15.0), # [°], [°] ] coords2 = [ ( +90.0, +15.0), # [°], [°] (-178.0, -88.0), # [°], [°] (+140.4, +35.8), # [°], [°] ( -91.0, +15.0), # [°], [°] ] # Define number of points ... npoints = [3, 4, 8, 16, 1000] # [#] # Create short-hand and make output directory ... dName = f'{args.absPathToRepo}/tests/{os.path.basename(__file__).removesuffix(".py")}' if not os.path.exists(dName): os.makedirs(dName) # ************************************************************************** # Create a pool of workers ... with multiprocessing.Pool(args.nChild) as pObj: # Loop over tests ... for i, (coord1, coord2) in enumerate(zip(coords1, coords2, strict = True)): # Determine file name ... pname = f"{dName}/greatCircle{i:d}.png" if not args.quiet: print(f" > Making \"{pname}\" ...") # Check that the user wants to make plots ... if not args.dontMakePlots: # Create figure ... fg = matplotlib.pyplot.figure( dpi = 100, # NOTE: Reduce DPI to make test quicker. figsize = (12.8, 7.2), ) # Create axis ... ax = pyguymer3.geo.add_axis( fg, add_coastlines = False, # NOTE: Do not draw coastlines so that changes in GSHGG do not change the image. add_gridlines = True, debug = args.debug, eps = args.eps, nIter = None, tol = args.tol, ) # Configure axis ... pyguymer3.geo.add_map_background( ax, debug = args.debug, resolution = "large1024px", # NOTE: Reduce size to make test quicker. ) # Loop over number of points ... for c, npoint in enumerate(npoints): # Determine file name ... jname = f"{dName}/greatCircle{i:d}_{c:d}.geojson" if not args.quiet: print(f" > Making \"{jname}\" ...") # Find the great circle ... circle = pyguymer3.geo.great_circle( coord1[0], coord1[1], coord2[0], coord2[1], debug = args.debug, eps = args.eps, maxdist = None, nIter = None, npoint = npoint, ) # Save GeoJSON ... # NOTE: As of 4/Aug/2025, the Python module "geojson" just # converts the object to a Python dictionary and then it # just calls the standard "json.dump()" function to format # the Python dictionary as text. There is no way to # specify the precision of the written string. # Fortunately, if you have no shame, then you can load and # then dump the string again, see: # * https://stackoverflow.com/a/29066406 with open(jname, "wt", encoding = "utf-8") as fObj: json.dump( json.loads( geojson.dumps( circle, ensure_ascii = False, indent = 4, sort_keys = True, ), parse_float = lambda x: round(float(x), 4), # NOTE: 0.0001° is approximately 11.1 m. ), fObj, ensure_ascii = False, indent = 4, sort_keys = True, ) # Check that the user wants to make plots ... if not args.dontMakePlots: # Loop over lines in the great circle ... for line in pyguymer3.geo.extract_lines(circle): # Extract the coordinates from this line ... coords = numpy.array(line.coords) # [°] # Transform coordinates ... # NOTE: See https://stackoverflow.com/a/52861074 points = cartopy.crs.Robinson().transform_points(cartopy.crs.Geodetic(), coords[:, 0], coords[:, 1]) # Plot great circle ... ax.plot( points[:, 0], points[:, 1], transform = cartopy.crs.Robinson(), linewidth = 1.0, color = matplotlib.colormaps["turbo"](float(c) / float(len(npoints) - 1)), ) # Check that the user wants to make plots ... if not args.dontMakePlots: # Configure figure ... fg.tight_layout() # Save figure ... fg.savefig(pname) matplotlib.pyplot.close(fg) # Optimise figure ... pyguymer3.image.optimise_image( pname, debug = args.debug, pool = pObj, strip = True, timeout = args.timeout, ) # Close the pool of worker processes and wait for all of the tasks to # finish ... # NOTE: The "__exit__()" call of the context manager for # "multiprocessing.Pool()" calls "terminate()" instead of # "join()", so I must manage the end of the pool of worker # processes myself. pObj.close() pObj.join()