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 CLI
import Configuration.Defaults
import ExitCodes
usage = '%prog [options] <well-known text representation>'
-
-# -h (help) Conflicts with -h HOSTNAME
-parser = OptionParser(usage=usage, add_help_option = False)
+parser = CLI.default_option_parser(usage)
# Use this module's docstring as the description.
parser.description = __doc__.strip()
-parser.add_option('-h',
- '--host',
- help='The hostname/address where the database is located.',
- default=Configuration.Defaults.DATABASE_HOST)
-
-parser.add_option('-d',
- '--database',
- help='The database in which the population data are stored.',
- default=Configuration.Defaults.DATABASE_NAME)
-
-parser.add_option('-U',
- '--username',
- help='The username who has access to the database.',
- default=Configuration.Defaults.DATABASE_USERNAME)
parser.add_option('-s',
'--srid',
raise SystemExit(ExitCodes.NOT_ENOUGH_ARGS)
-conn = pgdb.connect(host=options.host,
- database=options.database,
- user=options.username)
-
-cursor = conn.cursor()
-
-# We're ready to build our query, one step at a time. Firsy, we store
-# the Text->Geom conversion in a variable; this just makes the query a
-# little easier to read.
-geometric_object = "ST_GeomFromText('%s', %d)" % (args[0], options.srid)
-
-# We want to compute the population "under" the geometric object. We
-# can compute the percentage of a block that is covered by taking the
-# area of (the intersection of the object and the block) divided by
-# the total area of the block.
-#
-# Once we know the percentage covered, we just multiply that value by
-# the total population in the block to find the population that is
-# covered. The sum of these values over all blocks is our final
-# result.
-#
-query = """
-SELECT SUM(sf1_blocks.pop100 *
- ( ST_Area(ST_Intersection(%s, tiger.the_geom))
- / ST_Area(tiger.the_geom) )
- ) AS covered_population
-""" % geometric_object
-
-
-# Join our two block tables, so that we have both the demographic
-# and geometric data.
-query += \
-"""
-FROM (sf1_blocks INNER JOIN tiger
- ON sf1_blocks.tiger_blkidfp00 = tiger.blkidfp00)
-"""
-
-
-# We only need to calculate the covered population for the blocks
-# that actually intersect our object.
-query += \
-"""
-WHERE (ST_Intersects(%s, tiger.the_geom))
-""" % geometric_object
-
-
-# And we only take the first result, since they're all going to be the
-# same (our query returns the sum once for each block).
-query += \
-"""
-LIMIT 1
-"""
+cdb = Census.Database(options.host,
+ options.database,
+ options.username,
+ options.srid)
-cursor.execute(query)
-rows = cursor.fetchall()
+population = cdb.find_contained_population(args[0])
-if len(rows) > 0:
- population = rows[0][0]
+if (population != None):
print population
else:
print 'Error: No rows returned.'
raise SystemExit(ExitCodes.NO_RESULTS)
-
-conn.close()