bin/wkt2pop

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