bin/wkt2pop

   1 #!/usr/bin/python
   2
   3 """
   4 Find the total population contained within a geometric object.
   5
   6 Our input is an OGC Well-Known Text[1] string. This string is used as
   7 part of a database query that finds the population contained within
   8 (i.e. 'underneath') the geometric object corresponding to the WKT
   9 string.
  10
  11 [1] http://en.wikipedia.org/wiki/Well-known_text
  12 """
  13
  14 import sys
  15 import os
  16 import site
  17
  18 # Basically, add '../src' to our path.
  19 # Needed for the imports that follow.
  20 site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + '/../src')
  21
  22 import Census
  23 import CLI
  24 import Configuration.Defaults
  25 import ExitCodes
  26
  27 usage = '%prog [options] <well-known text representation>'
  28 parser = CLI.default_option_parser(usage)
  29
  30 # Use this module's docstring as the description.
  31 parser.description = __doc__
  32
  33
  34 parser.add_option('-s',
  35                   '--srid',
  36                   type="int",
  37                   help="SRID of the input geometry. Defaults to %s." % Configuration.Defaults.SRID,
  38                   default=Configuration.Defaults.SRID)
  39
  40
  41 (options, args) = parser.parse_args()
  42
  43 if len(args) < 1:
  44     print "\nERROR: You must supply a geometric object in Well-Known Text format.\n"
  45     parser.print_help()
  46     print '' # Print a newline.
  47     raise SystemExit(ExitCodes.NOT_ENOUGH_ARGS)
  48
  49
  50 cdb = Census.Database(options.host,
  51                       options.database,
  52                       options.username,
  53                       options.srid)
  54
  55 population = cdb.find_contained_population(args[0])
  56
  57 if (population != None):
  58     print population
  59 else:
  60     print 'Error: No rows returned.'
  61     raise SystemExit(ExitCodes.NO_RESULTS)