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 import os
  10 import pgdb
  11 import site
  12 import sys
  13
  14 # Basically, add '../src' to our path.
  15 # Needed for the imports that follow.
  16 site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + '/../src')
  17
  18 import CLI
  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
  30 parser = CLI.default_option_parser()
  31
  32 # Use this module's docstring as the description.
  33 parser.description = __doc__
  34
  35 parser.add_option('-s',
  36                   '--state',
  37                   help='The FIPS id of the State whose roads you would like.')
  38
  39 (options, args) = parser.parse_args()
  40
  41
  42 conn = pgdb.connect(host=options.host,
  43                     database=options.database,
  44                     user=options.username)
  45
  46
  47 # We'll use this cursor for all of our queries.
  48 cursor = conn.cursor()
  49
  50 # If no state is passed on the command line, we want to select the
  51 # roads for all states.  "... WHERE statefp=statefp ..." will
  52 # accomplish this.
  53 statefp = 'statefp'
  54 if (options.state != None):
  55     # The statefp column is a string, so we need to add single quotes
  56     # if we're going to specify it.
  57     statefp = "'%s'" % options.state
  58
  59 lines_query = """
  60 SELECT gid, tlid, fullname, ST_AsKml(the_geom)
  61 FROM tiger_lines
  62 WHERE statefp=%s
  63 """ % statefp
  64
  65 cursor.execute(lines_query)
  66 rows = cursor.fetchall()
  67 doc = KML.Document()
  68
  69 for row in rows:
  70     placemark = KML.Placemark()
  71
  72     # Name = "Street name (tlid)"
  73     fullname = row[2]
  74
  75     if (fullname == None):
  76         # Some streets don't have a fullname.
  77         fullname = 'Unknown'
  78
  79     name = KML.Name(fullname + ' (' + str(row[1]) + ')')
  80
  81     placemark.children.append(name)
  82     geometry = KML.RawText(row[3])
  83     placemark.children.append(geometry)
  84     doc.children.append(placemark)
  85
  86 doc.print_kml()
  87
  88 conn.close()