Added the Census module.

[dead/census-tools.git] / bin / find_avg_population_density

diff --git a/bin/find_avg_population_density b/bin/find_avg_population_density
index 05e2733928765e16b253cbe7b5eeb478f9393cdb..712db20f96c3c53465d1b8131826cb37547fb88d 100755 (executable)
--- a/bin/find_avg_population_density
+++ b/bin/find_avg_population_density
@@ -7,18 +7,17 @@ Find the average population density of a set of GPS coordinates.
 import sys
 import os
 import site
-import pgdb
 from optparse import OptionParser
 
 # Basically, add '../src' to our path.
 # Needed for the imports that follow.
 site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + '/../src')
 
+import Census
 import Configuration.Defaults
 import ExitCodes
 import GPS
 import StringUtils
-import SummaryFile1
 
 
 """
@@ -60,6 +59,12 @@ parser.add_option('-U',
                   help='The username who has access to the database.',
                   default=Configuration.Defaults.DATABASE_USERNAME)
 
+parser.add_option('-s',
+                  '--srid',
+                  type="int",
+                  help="SRID of the input geometry. Defaults to %s." % Configuration.Defaults.SRID,
+                  default=Configuration.Defaults.SRID)
+
 (options, args) = parser.parse_args()
 
 if len(args) < 2:
@@ -73,38 +78,17 @@ coords = GPS.Coordinates()
 coords.longitude = float(args[0])
 coords.latitude = float(args[1])
 
-conn = pgdb.connect(host=options.host,
-                    database=options.database,
-                    user=options.username)
-
-cursor = conn.cursor()
-
-###########
-# WARNING #
-###########
-#
-# Most GIS software, including PostGIS and the associated libraries,
-# store and manipulate GPS coordinates in (longitude, latitude) format
-# rather than (latitude, longitude) format.
-#
-
-query = """
-SELECT population_density
-FROM (sf1_blocks INNER JOIN tiger
-      ON sf1_blocks.tiger_blkidfp00=tiger.blkidfp00)
-WHERE ST_Contains(tiger.the_geom,
-                  ST_SetSRID(ST_Point(%.6f, %.6f), 4269));
-""" % (coords.longitude, coords.latitude)
-
-cursor.execute(query)
-rows = cursor.fetchall()
-
-if len(rows) > 0:
-    avg_density = rows[0][0]
+cdb = Census.Database(options.host,
+                      options.database,
+                      options.username,
+                      options.srid)
+
+avg_density = cdb.find_average_population_density(coords)
+
+if (avg_density != None):
     print str(avg_density)
 else:
     print 'Error: No rows returned.'
     print 'Did you pass (longitude, latitude) in the correct order?'
     raise SystemExit(ExitCodes.NO_RESULTS)
-    
-conn.close()
+