added the actual batch distance script

src/batch_distance.py

@@ -0,0 +1,99 @@
+# Batch_Distance.py: Batch process a bunch of distance measurements.
+
+import sys
+import argparse
+import csv
+import json
+import math
+import configparser
+import urllib.parse
+import urllib.request
+
+
+class GeocodingError(RuntimeError):
+    pass
+
+
+def geocode_google(config, address):
+    apikey = config['google']['apikey']
+    if not apikey:
+        raise GeocodingError("Google API key not specified")
+    query = { 'key': apikey, 'address': address, 'region': 'us'}
+    url = 'https://maps.googleapis.com/maps/api/geocode/json?' + \
+          urllib.parse.urlencode(query, quote_via=urllib.parse.quote)
+    with urllib.request.urlopen(url) as response:
+        if response.status == 200:
+            apireturn = json.loads(response.read())
+            stat = apireturn['status']
+            if stat == 'OK':
+                results = apireturn['results']
+                if len(results) > 1:
+                    raise GeocodingError(f"Google API returned ambiguous results (total count {len(results)})")
+                coords = results[0]['geometry']['location']
+                return coords['lat'], coords['lng']
+            elif stat == 'ZERO_RESULTS':
+                return None
+            else:
+                raise GeocodingError(f"Google API returns status of {stat}")
+        else:
+            raise GeocodingError(f"Google API returns {response.status} HTTP status code")
+
+
+OFFICE_LOCATION = (40.0187905, -105.2764775)  # office location - 1433 Pearl Street, Boulder, CO
+RADIUS = 6371.0 * 1000.0                      # Earth radius in meters
+METERS_PER_MILE = 1852.0                      # number of meters per mile
+
+
+def distance_miles(point1, point2):
+    Φ1 = math.radians(point1[0])
+    Φ2 = math.radians(point2[0])
+    ΔΦ = math.radians(point2[0] - point1[0])
+    Δλ = math.radians(point2[1] - point1[1])
+    a = math.sin(ΔΦ / 2.0) * math.sin(ΔΦ / 2.0) + math.cos(Φ1) * math.cos(Φ2) * math.sin(Δλ / 2.0) * math.sin(Δλ / 2.0)
+    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1.0 - a))
+    return RADIUS * c / METERS_PER_MILE
+
+
+THRESHOLD_RADIUS = 15.0   # number of miles in "acceptable" threshold
+ERROR_BAR_WIDTH = 0.5     # number of miles in "error bar" surrounding threshold
+
+
+def classify_distance(dist):
+    if dist > (THRESHOLD_RADIUS + ERROR_BAR_WIDTH / 2):
+        return 'RED'
+    if dist >= (THRESHOLD_RADIUS - ERROR_BAR_WIDTH / 2):
+        return 'YELLOW'
+    return 'GREEN'
+
+
+cmdline_parser = argparse.ArgumentParser()
+cmdline_parser.add_argument('input', help='The input file containing locations to be checked.')
+cmdline_parser.add_argument('output', nargs='?', help='The output file name that will receive the processed data.')
+cmdline_parser.add_argument('-C', '--config', default='geoapi.ini', help='The geocoding API configuration file')
+
+
+def main(args):
+    opts = cmdline_parser.parse_args(args)
+    config = configparser.ConfigParser()
+    config.read(opts.config)
+    output_name = opts.output
+    if not output_name:
+        output_name = opts.input + '.out'
+    with open(opts.input, newline='') as input_file:
+        dialect = csv.Sniffer().sniff(input_file.read(1024))
+        input_file.seek(0)
+        reader = csv.reader(input_file, dialect)
+        with open(output_name, mode='w') as output_file:
+            writer = csv.writer(output_file, dialect)
+            for in_row in reader:
+                coords = geocode_google(config, in_row[1])
+                if coords:
+                    dist = distance_miles(OFFICE_LOCATION, coords)
+                    out_row = [in_row[0], in_row[1], coords[0], coords[1], dist, classify_distance(dist)]
+                else:
+                    out_row = [in_row[0], in_row[1], '*** Unable to locate']
+                writer.writerow(out_row)
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))