bin/lines2kml

   1 #!/usr/bin/env python
   2
   3 """
   4 Export line (road) geometries from the database to Keyhole Markup
   5 Language (KML). The exported roads should have both a human-readable
   6 name and a globally-unique identifier (gid).
   7 """
   8
   9 from optparse import OptionParser
  10 import os
  11 import pgdb
  12 import site
  13 import sys
  14
  15 # Basically, add '../src' to our path.
  16 # Needed for the imports that follow.
  17 site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + '/../src')
  18
  19 import Configuration.Defaults
  20 import ExitCodes
  21 import KML
  22
  23
  24 """
  25 Parse the command line options. All of these are optional; defaults
  26 are provided for the database information and the output is written
  27 to stdout.
  28 """
  29 # -h (help) Conflicts with -h HOSTNAME
  30 parser = OptionParser(add_help_option = False)
  31
  32 # Use this module's docstring as the description.
  33 parser.description = __doc__.strip()
  34
  35 parser.add_option('-h',
  36                   '--host',
  37                   help='The hostname/address where the database is located.',
  38                   default=Configuration.Defaults.DATABASE_HOST)
  39
  40 parser.add_option('-d',
  41                   '--database',
  42                   help='The database in which the population data are stored.',
  43                   default=Configuration.Defaults.DATABASE_NAME)
  44
  45 parser.add_option('-U',
  46                   '--username',
  47                   help='The username who has access to the database.',
  48                   default=Configuration.Defaults.DATABASE_USERNAME)
  49
  50 parser.add_option('-s',
  51                   '--state',
  52                   help='The FIPS id of the State whose roads you would like.')
  53
  54 (options, args) = parser.parse_args()
  55
  56
  57 conn = pgdb.connect(host=options.host,
  58                     database=options.database,
  59                     user=options.username)
  60
  61
  62 # We'll use this cursor for all of our queries.
  63 cursor = conn.cursor()
  64
  65 # If no state is passed on the command line, we want to select the
  66 # roads for all states.  "... WHERE statefp=statefp ..." will
  67 # accomplish this.
  68 statefp = 'statefp'
  69 if (options.state != None):
  70     # The statefp column is a string, so we need to add single quotes
  71     # if we're going to specify it.
  72     statefp = "'%s'" % options.state
  73
  74 lines_query = """
  75 SELECT gid, tlid, fullname, ST_AsKml(the_geom)
  76 FROM tiger_lines
  77 WHERE statefp=%s
  78 """ % statefp
  79
  80 cursor.execute(lines_query)
  81 rows = cursor.fetchall()
  82 doc = KML.Document()
  83
  84 for row in rows:
  85     placemark = KML.Placemark()
  86
  87     # Name = "Street name (tlid)"
  88     fullname = row[2]
  89
  90     if (fullname == None):
  91         # Some streets don't have a fullname.
  92         fullname = 'Unknown'
  93
  94     name = KML.Name(fullname + ' (' + str(row[1]) + ')')
  95
  96     placemark.children.append(name)
  97     geometry = KML.RawText(row[3])
  98     placemark.children.append(geometry)
  99     doc.children.append(placemark)
 100
 101 doc.print_kml()
 102
 103 conn.close()