shape_importer.py

#!/usr/bin/python2.4
#
# Copyright 2007 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""A utility program to help add shapes to an existing GTFS feed.

Requires the ogr python package.
"""

__author__ = 'chris.harrelson.code@gmail.com (Chris Harrelson)'

import csv
import glob
import ogr
import os
import shutil
import sys
import tempfile
import transitfeed
from transitfeed import shapelib
from transitfeed import util
import zipfile


class ShapeImporterError(Exception):
  pass


def PrintColumns(shapefile):
  """
  Print the columns of layer 0 of the shapefile to the screen.
  """
  ds = ogr.Open(shapefile)
  layer = ds.GetLayer(0)
  if len(layer) == 0:
    raise ShapeImporterError("Layer 0 has no elements!")

  feature = layer.GetFeature(0)
  print "%d features" % feature.GetFieldCount()
  for j in range(0, feature.GetFieldCount()):
    print '--' + feature.GetFieldDefnRef(j).GetName() + \
          ': ' + feature.GetFieldAsString(j)


def AddShapefile(shapefile, graph, key_cols):
  """
  Adds shapes found in the given shape filename to the given polyline
  graph object.
  """
  ds = ogr.Open(shapefile)
  layer = ds.GetLayer(0)

  for i in range(0, len(layer)):
    feature = layer.GetFeature(i)

    geometry = feature.GetGeometryRef()

    if key_cols:
      key_list = []
      for col in key_cols:
        key_list.append(str(feature.GetField(col)))
      shape_id = '-'.join(key_list)
    else:
      shape_id = '%s-%d' % (shapefile, i)

    poly = shapelib.Poly(name=shape_id)
    for j in range(0, geometry.GetPointCount()):
      (lat, lng) = (round(geometry.GetY(j), 15), round(geometry.GetX(j), 15))
      poly.AddPoint(shapelib.Point.FromLatLng(lat, lng))
    graph.AddPoly(poly)

  return graph


def GetMatchingShape(pattern_poly, trip, matches, max_distance, verbosity=0):
  """
  Tries to find a matching shape for the given pattern Poly object,
  trip, and set of possibly matching Polys from which to choose a match.
  """
  if len(matches) == 0:
    print ('No matching shape found within max-distance %d for trip %s '
           % (max_distance, trip.trip_id))
    return None

  if verbosity >= 1:
    for match in matches:
      print "match: size %d" % match.GetNumPoints()
  scores = [(pattern_poly.GreedyPolyMatchDist(match), match)
            for match in matches]

  scores.sort()

  if scores[0][0] > max_distance:
    print ('No matching shape found within max-distance %d for trip %s '
           '(min score was %f)'
           % (max_distance, trip.trip_id, scores[0][0]))
    return None

  return scores[0][1]

def AddExtraShapes(extra_shapes_txt, graph):
  """
  Add extra shapes into our input set by parsing them out of a GTFS-formatted
  shapes.txt file.  Useful for manually adding lines to a shape file, since it's
  a pain to edit .shp files.
  """

  print "Adding extra shapes from %s" % extra_shapes_txt
  try:
    tmpdir = tempfile.mkdtemp()
    shutil.copy(extra_shapes_txt, os.path.join(tmpdir, 'shapes.txt'))
    loader = transitfeed.ShapeLoader(tmpdir)
    schedule = loader.Load()
    for shape in schedule.GetShapeList():
      print "Adding extra shape: %s" % shape.shape_id
      graph.AddPoly(ShapeToPoly(shape))
  finally:
    if tmpdir:
      shutil.rmtree(tmpdir)


# Note: this method lives here to avoid cross-dependencies between
# shapelib and transitfeed.
def ShapeToPoly(shape):
  poly = shapelib.Poly(name=shape.shape_id)
  for lat, lng, distance in shape.points:
    point = shapelib.Point.FromLatLng(round(lat, 15), round(lng, 15))
    poly.AddPoint(point)
  return poly


def ValidateArgs(options_parser, options, args):
  if not (args and options.source_gtfs and options.dest_gtfs):
    options_parser.error("You must specify a source and dest GTFS file, "
                         "and at least one source shapefile")


def DefineOptions():
  usage = \
"""%prog [options] --source_gtfs=<input GTFS.zip> --dest_gtfs=<output GTFS.zip>\
 <input.shp> [<input.shp>...]

Try to match shapes in one or more SHP files to trips in a GTFS file."""
  options_parser = util.OptionParserLongError(
      usage=usage, version='%prog '+transitfeed.__version__)
  options_parser.add_option("--print_columns",
                            action="store_true",
                            default=False,
                            dest="print_columns",
                            help="Print column names in shapefile DBF and exit")
  options_parser.add_option("--keycols",
                            default="",
                            dest="keycols",
                            help="Comma-separated list of the column names used"
                                 "to index shape ids")
  options_parser.add_option("--max_distance",
                            type="int",
                            default=150,
                            dest="max_distance",
                            help="Max distance from a shape to which to match")
  options_parser.add_option("--source_gtfs",
                            default="",
                            dest="source_gtfs",
                            metavar="FILE",
                            help="Read input GTFS from FILE")
  options_parser.add_option("--dest_gtfs",
                            default="",
                            dest="dest_gtfs",
                            metavar="FILE",
                            help="Write output GTFS with shapes to FILE")
  options_parser.add_option("--extra_shapes",
                            default="",
                            dest="extra_shapes",
                            metavar="FILE",
                            help="Extra shapes.txt (CSV) formatted file")
  options_parser.add_option("--verbosity",
                            type="int",
                            default=0,
                            dest="verbosity",
                            help="Verbosity level. Higher is more verbose")
  return options_parser


def main(key_cols):
  print 'Parsing shapefile(s)...'
  graph = shapelib.PolyGraph()
  for arg in args:
    print '  ' + arg
    AddShapefile(arg, graph, key_cols)

  if options.extra_shapes:
    AddExtraShapes(options.extra_shapes, graph)

  print 'Loading GTFS from %s...' % options.source_gtfs
  schedule = transitfeed.Loader(options.source_gtfs).Load()
  shape_count = 0
  pattern_count = 0

  verbosity = options.verbosity

  print 'Matching shapes to trips...'
  for route in schedule.GetRouteList():
    print 'Processing route', route.route_short_name
    patterns = route.GetPatternIdTripDict()
    for pattern_id, trips in patterns.iteritems():
      pattern_count += 1
      pattern = trips[0].GetPattern()

      poly_points = [shapelib.Point.FromLatLng(p.stop_lat, p.stop_lon)
                     for p in pattern]
      if verbosity >= 2:
        print "\npattern %d, %d points:" % (pattern_id, len(poly_points))
        for i, (stop, point) in enumerate(zip(pattern, poly_points)):
          print "Stop %d '%s': %s" % (i + 1, stop.stop_name, point.ToLatLng())

      # First, try to find polys that run all the way from
      # the start of the trip to the end.
      matches = graph.FindMatchingPolys(poly_points[0], poly_points[-1],
                                        options.max_distance)
      if not matches:
        # Try to find a path through the graph, joining
        # multiple edges to find a path that covers all the
        # points in the trip.  Some shape files are structured
        # this way, with a polyline for each segment between
        # stations instead of a polyline covering an entire line.
        shortest_path = graph.FindShortestMultiPointPath(poly_points,
                                                         options.max_distance,
                                                         verbosity=verbosity)
        if shortest_path:
          matches = [shortest_path]
        else:
          matches = []

      pattern_poly = shapelib.Poly(poly_points)
      shape_match = GetMatchingShape(pattern_poly, trips[0],
                                     matches, options.max_distance,
                                     verbosity=verbosity)
      if shape_match:
        shape_count += 1
        # Rename shape for readability.
        shape_match = shapelib.Poly(points=shape_match.GetPoints(),
                                           name="shape_%d" % shape_count)
        for trip in trips:
          try:
            shape = schedule.GetShape(shape_match.GetName())
          except KeyError:
            shape = transitfeed.Shape(shape_match.GetName())
            for point in shape_match.GetPoints():
              (lat, lng) = point.ToLatLng()
              shape.AddPoint(lat, lng)
            schedule.AddShapeObject(shape)
          trip.shape_id = shape.shape_id

  print "Matched %d shapes out of %d patterns" % (shape_count, pattern_count)
  schedule.WriteGoogleTransitFeed(options.dest_gtfs)


if __name__ == '__main__':
  # Import psyco if available for better performance.
  try:
    import psyco
    psyco.full()
  except ImportError:
    pass

  options_parser = DefineOptions()
  (options, args) = options_parser.parse_args()

  ValidateArgs(options_parser, options, args)

  if options.print_columns:
    for arg in args:
      PrintColumns(arg)
    sys.exit(0)

  key_cols = options.keycols.split(',')

  main(key_cols)