Support for command line arguments

qsomap.py

@@ -1,16 +1,18 @@
 #!/usr/bin/env python3
 
+import sys
 import svgwrite
 import numpy as np
 import matplotlib.pyplot as pp
 from matplotlib.colors import hsv_to_rgb
 import json
 import random
+import argparse
 
 REF_LATITUDE = 49.58666
 REF_LONGITUDE = 11.01250
-# REF_LATITUDE = 1
-# REF_LONGITUDE = 0
+# REF_LATITUDE = -30
+# REF_LONGITUDE = 90
 
 
 def map_azimuthal_equidistant(lat, lon, ref_lat, ref_lon, R=1):
@@ -63,6 +65,7 @@ def random_country_color():
     return f"#{r:02x}{g:02x}{b:02x}"
 
 
+def render(ref_lat, ref_lon, output_stream):
     random.seed(0)
 
     """ Test code
@@ -73,15 +76,15 @@ for lat in test_lat:
         for lon in test_lon:
             x, y = map_azimuthal_equidistant(np.array([lat]), np.array([lon]), np.pi/2, 0)
 
-        print(f"{lat*180/np.pi:6.3f}, {lon*180/np.pi:6.3f} => {x[0]:6.3f}, {y[0]:6.3f}")
+            print(f"{lat*180/np.pi:6.3f}, {lon*180/np.pi:6.3f} => {x[0]:6.3f}, {y[0]:6.3f}", file=sys.stderr)
     """
 
-print("Loading Geodata…")
+    print("Loading Geodata…", file=sys.stderr)
 
     with open('geo-countries/data/countries.geojson', 'r') as jfile:
         geojson = json.load(jfile)
 
-print("Finding boundaries…")
+    print("Finding boundaries…", file=sys.stderr)
 
     # key: 3-letter country identifier
     # data: {full_name, numpy.array(coordinates), numpy.array(proj_coordinates)}.
@@ -101,7 +104,7 @@ for feature in features:
         if key in simplegeodata.keys():
             key = name
 
-    print(f"Preparing {key} ({name})…")
+        print(f"Preparing {key} ({name})…", file=sys.stderr)
 
         multipoly = feature['geometry']['coordinates']
 
@@ -121,8 +124,8 @@ for feature in features:
 
         simplegeodata[key] = {"name": name, "coordinates": conv_polys}
 
-ref_lat = REF_LATITUDE * np.pi / 180
-ref_lon = REF_LONGITUDE * np.pi / 180
+    ref_lat = ref_lat * np.pi / 180
+    ref_lon = ref_lon * np.pi / 180
 
     R = 500
 
@@ -215,7 +218,7 @@ doc.add(doc.circle(center=(R, R), r=R, fill='#ddeeff',
                        stroke_width=1, stroke='black'))
 
     for k, v in simplegeodata.items():
-    print(f"Exporting {k}…")
+        print(f"Exporting {k}…", file=sys.stderr)
 
         color = random_country_color()
 
@@ -302,11 +305,10 @@ for x in range(0, 26):
             sectorname = chr(ord('A')+x) + chr(ord('A')+y)
     """
 
+    print(f"Writing output…", file=sys.stderr)
+    doc.write(output_stream, pretty=True)
 
-print(f"Saving {doc.filename}…")
-doc.save(pretty=True)
-
-exit(0)
+    return
 
     # Debug Plot
 
@@ -330,3 +332,20 @@ pp.axis('equal')
 
     pp.show()
 
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+            description="Render an azimuthal equidistant map of the world " +
+                        "centered on the given point")
+
+    parser.add_argument(metavar='ref-lat', type=float, dest='ref_lat',
+                        help='Reference Latitude')
+    parser.add_argument(metavar='ref-lon', type=float, dest='ref_lon',
+                        help='Reference Longitude')
+    parser.add_argument('-o', '--output-file', type=argparse.FileType('w'),
+                        help='The output SVG file (default: print to stdout)',
+                        default=sys.stdout)
+
+    args = parser.parse_args()
+
+    render(args.ref_lat, args.ref_lon, args.output_file)