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 from optparse import OptionParser
  20
  21 # Basically, add '../src' to our path.
  22 # Needed for the imports that follow.
  23 site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + '/../src')
  24
  25 import Census
  26 import Configuration.Defaults
  27 import ExitCodes
  28
  29 usage = '%prog [options] <well-known text representation>'
  30
  31 # -h (help) Conflicts with -h HOSTNAME
  32 parser = OptionParser(usage=usage, add_help_option = False)
  33
  34 # Use this module's docstring as the description.
  35 parser.description = __doc__.strip()
  36
  37 parser.add_option('-h',
  38                   '--host',
  39                   help='The hostname/address where the database is located.',
  40                   default=Configuration.Defaults.DATABASE_HOST)
  41
  42 parser.add_option('-d',
  43                   '--database',
  44                   help='The database in which the population data are stored.',
  45                   default=Configuration.Defaults.DATABASE_NAME)
  46
  47 parser.add_option('-U',
  48                   '--username',
  49                   help='The username who has access to the database.',
  50                   default=Configuration.Defaults.DATABASE_USERNAME)
  51
  52 parser.add_option('-s',
  53                   '--srid',
  54                   type="int",
  55                   help="SRID of the input geometry. Defaults to %s." % Configuration.Defaults.SRID,
  56                   default=Configuration.Defaults.SRID)
  57
  58
  59 (options, args) = parser.parse_args()
  60
  61 if len(args) < 1:
  62     print "\nERROR: You must supply a geometric object in Well-Known Text format.\n"
  63     parser.print_help()
  64     print '' # Print a newline.
  65     raise SystemExit(ExitCodes.NOT_ENOUGH_ARGS)
  66
  67
  68 cdb = Census.Database(options.host,
  69                       options.database,
  70                       options.username,
  71                       options.srid)
  72
  73 population = cdb.find_contained_population(args[0])
  74
  75 if (population != None):
  76     print population
  77 else:
  78     print 'Error: No rows returned.'
  79     raise SystemExit(ExitCodes.NO_RESULTS)
  80