root/geojson/trunk/tests/geometry.txt

Tests of the geometry protocol
==============================

A dictionary can satisfy the protocol
-------------------------------------

  >>> g = {
  ...    "type": "Point",
  ...    "coordinates": [1.3, -54.23242]
  ... }

  >>> import geojson
  >>> import geojson.geometry

  Encoding

  >>> json = geojson.dumps(g)
  >>> json # doctest: +ELLIPSIS
  '{"type": "Point", "coordinates": [1..., -54...]}'

  Decoding

  >>> o = geojson.loads(json)
  >>> o # doctest: +ELLIPSIS
  {u'type': u'Point', u'coordinates': [1..., -54...]}


geometry class
---------------------

  >>> ls = geojson.geometry.LineString(((52.1, -34.131), (65.231, -34.234)))

  >>> ls.__geo_interface__ # doctest: +ELLIPSIS
  {'type': 'LineString', 'coordinates': ((52.100000000000001, -34.131), (65..., -34...))}

  >>> ls.type
  'LineString'
  >>> ls.coordinates # doctest: +ELLIPSIS
  ((52..., -34...), (65..., -34...))

  Encoding

  >>> json = geojson.dumps(ls)
  >>> json # doctest: +ELLIPSIS
  '{"type": "LineString", "coordinates": [[52..., -34...], [65..., -34...]]}'

  Decoding
  >>> geojson.loads(json) # doctest: +ELLIPSIS
  {u'type': u'LineString', u'coordinates': [[52..., -34...], [65..., -34...]]}

  >>> factory = lambda o: geojson.GeoJSON.to_instance(o, geojson.geometry)
  >>> geom = geojson.loads(json, object_hook=factory)
  >>> type(geom)
  <class 'geojson.geometry.LineString'>
  >>> geom.type
  'LineString'
  >>> geom.coordinates # doctest: +ELLIPSIS
  [[52..., -34...], [65..., -34...]]


  Test custom crs 
 
  >>> from geojson.crs import Named

  >>> coords = ((-1918145.0108183471, -4098018.9166399641), (-680004.67204747663, -3864394.3196185972))

  >>> ls = geojson.geometry.LineString(coords, crs=Named(properties=dict(name='EPSG:4326')))

  >>> ls.__geo_interface__ # doctest: +ELLIPSIS
  {'crs': {'type': 'name', 'properties': {'name': 'EPSG:4326'}}, 'type': 'LineString', 'coordinates': ((-1918145..., -4098018...), (-680004..., -3864394...))}

  It satisfies the geometry protocol

  >>> json = geojson.dumps(ls)
  >>> json # doctest: +ELLIPSIS
  '{"crs": {"type": "name", "properties": {"name": "EPSG:4326"}}, "type": "LineString", "coordinates": [[-1918145..., -4098018...], [-680004..., -3864394...]]}'

  Decoding
  >>> geojson.loads(json) # doctest: +ELLIPSIS
  {u'crs': {u'type': u'name', u'properties': {u'name': u'EPSG:4326'}}, u'type': u'LineString', u'coordinates': [[-1918145..., -4098018...], [-680004..., -3864394...]]}
 

  >>> factory = lambda o: geojson.GeoJSON.to_instance(o, geojson.geometry)
  >>> geom = geojson.loads(json, object_hook=factory)
  >>> type(geom)
  <class 'geojson.geometry.LineString'>
  >>> geom.type
  'LineString'
  >>> geom.coordinates # doctest: +ELLIPSIS
  [[-1918145..., -4098018...], [-680004..., -3864394...]]
 
Test the geo interface
----------------------

  >>> class PointThingy(object):
  ...     def __init__(self, x, y):
  ...         self.x = x
  ...         self.y = y
  ...     @property
  ...     def __geo_interface__(self):
  ...        return {"type": "Point", "coordinates": (self.x, self.y)}

  >>> ob = PointThingy(-106.0, 40.0)
  >>> ob.__geo_interface__['coordinates']  # doctest: +ELLIPSIS
  (-106..., 40...)
  >>> geojson.dumps(ob)  # doctest: +ELLIPSIS
  '{"type": "Point", "coordinates": [-106..., 40...]}'