713 lines
24 KiB
Python
713 lines
24 KiB
Python
"""
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The OGRGeometry is a wrapper for using the OGR Geometry class
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(see http://www.gdal.org/classOGRGeometry.html). OGRGeometry
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may be instantiated when reading geometries from OGR Data Sources
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(e.g. SHP files), or when given OGC WKT (a string).
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While the 'full' API is not present yet, the API is "pythonic" unlike
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the traditional and "next-generation" OGR Python bindings. One major
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advantage OGR Geometries have over their GEOS counterparts is support
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for spatial reference systems and their transformation.
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Example:
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>>> from django.contrib.gis.gdal import OGRGeometry, OGRGeomType, SpatialReference
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>>> wkt1, wkt2 = 'POINT(-90 30)', 'POLYGON((0 0, 5 0, 5 5, 0 5)'
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>>> pnt = OGRGeometry(wkt1)
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>>> print(pnt)
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POINT (-90 30)
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>>> mpnt = OGRGeometry(OGRGeomType('MultiPoint'), SpatialReference('WGS84'))
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>>> mpnt.add(wkt1)
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>>> mpnt.add(wkt1)
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>>> print(mpnt)
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MULTIPOINT (-90 30,-90 30)
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>>> print(mpnt.srs.name)
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WGS 84
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>>> print(mpnt.srs.proj)
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+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
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>>> mpnt.transform(SpatialReference('NAD27'))
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>>> print(mpnt.proj)
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+proj=longlat +ellps=clrk66 +datum=NAD27 +no_defs
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>>> print(mpnt)
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MULTIPOINT (-89.999930378602485 29.999797886557641,-89.999930378602485 29.999797886557641)
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The OGRGeomType class is to make it easy to specify an OGR geometry type:
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>>> from django.contrib.gis.gdal import OGRGeomType
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>>> gt1 = OGRGeomType(3) # Using an integer for the type
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>>> gt2 = OGRGeomType('Polygon') # Using a string
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>>> gt3 = OGRGeomType('POLYGON') # It's case-insensitive
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>>> print(gt1 == 3, gt1 == 'Polygon') # Equivalence works w/non-OGRGeomType objects
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True True
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"""
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import sys
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from binascii import a2b_hex, b2a_hex
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from ctypes import byref, c_char_p, c_double, c_ubyte, c_void_p, string_at
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from django.contrib.gis.gdal.base import GDALBase
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from django.contrib.gis.gdal.envelope import Envelope, OGREnvelope
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from django.contrib.gis.gdal.error import (
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GDALException, OGRIndexError, SRSException,
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)
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from django.contrib.gis.gdal.geomtype import OGRGeomType
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from django.contrib.gis.gdal.prototypes import geom as capi, srs as srs_api
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from django.contrib.gis.gdal.srs import CoordTransform, SpatialReference
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from django.contrib.gis.geometry.regex import hex_regex, json_regex, wkt_regex
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from django.utils import six
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from django.utils.encoding import force_bytes
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from django.utils.six.moves import range
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# For more information, see the OGR C API source code:
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# http://www.gdal.org/ogr__api_8h.html
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#
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# The OGR_G_* routines are relevant here.
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class OGRGeometry(GDALBase):
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"Generally encapsulates an OGR geometry."
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def __init__(self, geom_input, srs=None):
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"Initializes Geometry on either WKT or an OGR pointer as input."
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str_instance = isinstance(geom_input, six.string_types)
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# If HEX, unpack input to a binary buffer.
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if str_instance and hex_regex.match(geom_input):
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geom_input = six.memoryview(a2b_hex(geom_input.upper().encode()))
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str_instance = False
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# Constructing the geometry,
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if str_instance:
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wkt_m = wkt_regex.match(geom_input)
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json_m = json_regex.match(geom_input)
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if wkt_m:
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if wkt_m.group('srid'):
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# If there's EWKT, set the SRS w/value of the SRID.
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srs = int(wkt_m.group('srid'))
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if wkt_m.group('type').upper() == 'LINEARRING':
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# OGR_G_CreateFromWkt doesn't work with LINEARRING WKT.
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# See http://trac.osgeo.org/gdal/ticket/1992.
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g = capi.create_geom(OGRGeomType(wkt_m.group('type')).num)
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capi.import_wkt(g, byref(c_char_p(wkt_m.group('wkt').encode())))
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else:
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g = capi.from_wkt(byref(c_char_p(wkt_m.group('wkt').encode())), None, byref(c_void_p()))
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elif json_m:
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g = capi.from_json(geom_input.encode())
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else:
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# Seeing if the input is a valid short-hand string
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# (e.g., 'Point', 'POLYGON').
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OGRGeomType(geom_input)
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g = capi.create_geom(OGRGeomType(geom_input).num)
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elif isinstance(geom_input, six.memoryview):
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# WKB was passed in
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g = capi.from_wkb(bytes(geom_input), None, byref(c_void_p()), len(geom_input))
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elif isinstance(geom_input, OGRGeomType):
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# OGRGeomType was passed in, an empty geometry will be created.
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g = capi.create_geom(geom_input.num)
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elif isinstance(geom_input, self.ptr_type):
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# OGR pointer (c_void_p) was the input.
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g = geom_input
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else:
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raise GDALException('Invalid input type for OGR Geometry construction: %s' % type(geom_input))
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# Now checking the Geometry pointer before finishing initialization
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# by setting the pointer for the object.
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if not g:
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raise GDALException('Cannot create OGR Geometry from input: %s' % str(geom_input))
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self.ptr = g
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# Assigning the SpatialReference object to the geometry, if valid.
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if srs:
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self.srs = srs
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# Setting the class depending upon the OGR Geometry Type
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self.__class__ = GEO_CLASSES[self.geom_type.num]
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def __del__(self):
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"Deletes this Geometry."
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try:
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capi.destroy_geom(self._ptr)
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except (AttributeError, TypeError):
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pass # Some part might already have been garbage collected
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# Pickle routines
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def __getstate__(self):
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srs = self.srs
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if srs:
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srs = srs.wkt
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else:
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srs = None
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return bytes(self.wkb), srs
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def __setstate__(self, state):
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wkb, srs = state
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ptr = capi.from_wkb(wkb, None, byref(c_void_p()), len(wkb))
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if not ptr:
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raise GDALException('Invalid OGRGeometry loaded from pickled state.')
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self.ptr = ptr
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self.srs = srs
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@classmethod
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def from_bbox(cls, bbox):
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"Constructs a Polygon from a bounding box (4-tuple)."
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x0, y0, x1, y1 = bbox
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return OGRGeometry('POLYGON((%s %s, %s %s, %s %s, %s %s, %s %s))' % (
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x0, y0, x0, y1, x1, y1, x1, y0, x0, y0))
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@classmethod
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def from_gml(cls, gml_string):
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return cls(capi.from_gml(force_bytes(gml_string)))
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# ### Geometry set-like operations ###
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# g = g1 | g2
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def __or__(self, other):
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"Returns the union of the two geometries."
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return self.union(other)
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# g = g1 & g2
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def __and__(self, other):
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"Returns the intersection of this Geometry and the other."
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return self.intersection(other)
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# g = g1 - g2
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def __sub__(self, other):
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"Return the difference this Geometry and the other."
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return self.difference(other)
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# g = g1 ^ g2
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def __xor__(self, other):
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"Return the symmetric difference of this Geometry and the other."
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return self.sym_difference(other)
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def __eq__(self, other):
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"Is this Geometry equal to the other?"
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if isinstance(other, OGRGeometry):
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return self.equals(other)
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else:
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return False
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def __ne__(self, other):
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"Tests for inequality."
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return not (self == other)
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def __str__(self):
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"WKT is used for the string representation."
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return self.wkt
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# #### Geometry Properties ####
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@property
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def dimension(self):
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"Returns 0 for points, 1 for lines, and 2 for surfaces."
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return capi.get_dims(self.ptr)
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def _get_coord_dim(self):
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"Returns the coordinate dimension of the Geometry."
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return capi.get_coord_dim(self.ptr)
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def _set_coord_dim(self, dim):
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"Sets the coordinate dimension of this Geometry."
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if dim not in (2, 3):
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raise ValueError('Geometry dimension must be either 2 or 3')
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capi.set_coord_dim(self.ptr, dim)
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coord_dim = property(_get_coord_dim, _set_coord_dim)
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@property
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def geom_count(self):
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"The number of elements in this Geometry."
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return capi.get_geom_count(self.ptr)
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@property
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def point_count(self):
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"Returns the number of Points in this Geometry."
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return capi.get_point_count(self.ptr)
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@property
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def num_points(self):
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"Alias for `point_count` (same name method in GEOS API.)"
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return self.point_count
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@property
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def num_coords(self):
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"Alais for `point_count`."
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return self.point_count
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@property
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def geom_type(self):
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"Returns the Type for this Geometry."
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return OGRGeomType(capi.get_geom_type(self.ptr))
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@property
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def geom_name(self):
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"Returns the Name of this Geometry."
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return capi.get_geom_name(self.ptr)
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@property
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def area(self):
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"Returns the area for a LinearRing, Polygon, or MultiPolygon; 0 otherwise."
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return capi.get_area(self.ptr)
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@property
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def envelope(self):
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"Returns the envelope for this Geometry."
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# TODO: Fix Envelope() for Point geometries.
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return Envelope(capi.get_envelope(self.ptr, byref(OGREnvelope())))
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@property
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def extent(self):
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"Returns the envelope as a 4-tuple, instead of as an Envelope object."
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return self.envelope.tuple
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# #### SpatialReference-related Properties ####
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# The SRS property
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def _get_srs(self):
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"Returns the Spatial Reference for this Geometry."
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try:
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srs_ptr = capi.get_geom_srs(self.ptr)
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return SpatialReference(srs_api.clone_srs(srs_ptr))
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except SRSException:
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return None
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def _set_srs(self, srs):
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"Sets the SpatialReference for this geometry."
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# Do not have to clone the `SpatialReference` object pointer because
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# when it is assigned to this `OGRGeometry` it's internal OGR
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# reference count is incremented, and will likewise be released
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# (decremented) when this geometry's destructor is called.
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if isinstance(srs, SpatialReference):
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srs_ptr = srs.ptr
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elif isinstance(srs, six.integer_types + six.string_types):
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sr = SpatialReference(srs)
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srs_ptr = sr.ptr
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elif srs is None:
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srs_ptr = None
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else:
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raise TypeError('Cannot assign spatial reference with object of type: %s' % type(srs))
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capi.assign_srs(self.ptr, srs_ptr)
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srs = property(_get_srs, _set_srs)
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# The SRID property
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def _get_srid(self):
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srs = self.srs
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if srs:
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return srs.srid
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return None
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def _set_srid(self, srid):
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if isinstance(srid, six.integer_types) or srid is None:
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self.srs = srid
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else:
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raise TypeError('SRID must be set with an integer.')
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srid = property(_get_srid, _set_srid)
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# #### Output Methods ####
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@property
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def geos(self):
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"Returns a GEOSGeometry object from this OGRGeometry."
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from django.contrib.gis.geos import GEOSGeometry
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return GEOSGeometry(self.wkb, self.srid)
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@property
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def gml(self):
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"Returns the GML representation of the Geometry."
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return capi.to_gml(self.ptr)
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@property
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def hex(self):
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"Returns the hexadecimal representation of the WKB (a string)."
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return b2a_hex(self.wkb).upper()
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@property
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def json(self):
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"""
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Returns the GeoJSON representation of this Geometry.
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"""
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return capi.to_json(self.ptr)
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geojson = json
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@property
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def kml(self):
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"Returns the KML representation of the Geometry."
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return capi.to_kml(self.ptr, None)
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@property
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def wkb_size(self):
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"Returns the size of the WKB buffer."
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return capi.get_wkbsize(self.ptr)
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@property
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def wkb(self):
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"Returns the WKB representation of the Geometry."
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if sys.byteorder == 'little':
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byteorder = 1 # wkbNDR (from ogr_core.h)
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else:
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byteorder = 0 # wkbXDR
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sz = self.wkb_size
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# Creating the unsigned character buffer, and passing it in by reference.
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buf = (c_ubyte * sz)()
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capi.to_wkb(self.ptr, byteorder, byref(buf))
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# Returning a buffer of the string at the pointer.
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return six.memoryview(string_at(buf, sz))
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@property
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def wkt(self):
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"Returns the WKT representation of the Geometry."
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return capi.to_wkt(self.ptr, byref(c_char_p()))
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@property
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def ewkt(self):
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"Returns the EWKT representation of the Geometry."
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srs = self.srs
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if srs and srs.srid:
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return 'SRID=%s;%s' % (srs.srid, self.wkt)
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else:
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return self.wkt
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# #### Geometry Methods ####
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def clone(self):
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"Clones this OGR Geometry."
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return OGRGeometry(capi.clone_geom(self.ptr), self.srs)
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def close_rings(self):
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"""
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If there are any rings within this geometry that have not been
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closed, this routine will do so by adding the starting point at the
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end.
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"""
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# Closing the open rings.
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capi.geom_close_rings(self.ptr)
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def transform(self, coord_trans, clone=False):
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"""
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Transforms this geometry to a different spatial reference system.
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May take a CoordTransform object, a SpatialReference object, string
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WKT or PROJ.4, and/or an integer SRID. By default nothing is returned
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and the geometry is transformed in-place. However, if the `clone`
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keyword is set, then a transformed clone of this geometry will be
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returned.
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"""
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if clone:
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klone = self.clone()
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klone.transform(coord_trans)
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return klone
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# Depending on the input type, use the appropriate OGR routine
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# to perform the transformation.
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if isinstance(coord_trans, CoordTransform):
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capi.geom_transform(self.ptr, coord_trans.ptr)
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elif isinstance(coord_trans, SpatialReference):
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capi.geom_transform_to(self.ptr, coord_trans.ptr)
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elif isinstance(coord_trans, six.integer_types + six.string_types):
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sr = SpatialReference(coord_trans)
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capi.geom_transform_to(self.ptr, sr.ptr)
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else:
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raise TypeError('Transform only accepts CoordTransform, '
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'SpatialReference, string, and integer objects.')
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# #### Topology Methods ####
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def _topology(self, func, other):
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"""A generalized function for topology operations, takes a GDAL function and
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the other geometry to perform the operation on."""
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if not isinstance(other, OGRGeometry):
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raise TypeError('Must use another OGRGeometry object for topology operations!')
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# Returning the output of the given function with the other geometry's
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# pointer.
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return func(self.ptr, other.ptr)
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def intersects(self, other):
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"Returns True if this geometry intersects with the other."
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return self._topology(capi.ogr_intersects, other)
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def equals(self, other):
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"Returns True if this geometry is equivalent to the other."
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return self._topology(capi.ogr_equals, other)
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def disjoint(self, other):
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"Returns True if this geometry and the other are spatially disjoint."
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return self._topology(capi.ogr_disjoint, other)
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def touches(self, other):
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"Returns True if this geometry touches the other."
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return self._topology(capi.ogr_touches, other)
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def crosses(self, other):
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"Returns True if this geometry crosses the other."
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return self._topology(capi.ogr_crosses, other)
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def within(self, other):
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"Returns True if this geometry is within the other."
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return self._topology(capi.ogr_within, other)
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def contains(self, other):
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"Returns True if this geometry contains the other."
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return self._topology(capi.ogr_contains, other)
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def overlaps(self, other):
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"Returns True if this geometry overlaps the other."
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return self._topology(capi.ogr_overlaps, other)
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# #### Geometry-generation Methods ####
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def _geomgen(self, gen_func, other=None):
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"A helper routine for the OGR routines that generate geometries."
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if isinstance(other, OGRGeometry):
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return OGRGeometry(gen_func(self.ptr, other.ptr), self.srs)
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else:
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return OGRGeometry(gen_func(self.ptr), self.srs)
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@property
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def boundary(self):
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"Returns the boundary of this geometry."
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return self._geomgen(capi.get_boundary)
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@property
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def convex_hull(self):
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"""
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Returns the smallest convex Polygon that contains all the points in
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this Geometry.
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"""
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return self._geomgen(capi.geom_convex_hull)
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def difference(self, other):
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"""
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Returns a new geometry consisting of the region which is the difference
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of this geometry and the other.
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"""
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return self._geomgen(capi.geom_diff, other)
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def intersection(self, other):
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"""
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Returns a new geometry consisting of the region of intersection of this
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geometry and the other.
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"""
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return self._geomgen(capi.geom_intersection, other)
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def sym_difference(self, other):
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"""
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Returns a new geometry which is the symmetric difference of this
|
|
geometry and the other.
|
|
"""
|
|
return self._geomgen(capi.geom_sym_diff, other)
|
|
|
|
def union(self, other):
|
|
"""
|
|
Returns a new geometry consisting of the region which is the union of
|
|
this geometry and the other.
|
|
"""
|
|
return self._geomgen(capi.geom_union, other)
|
|
|
|
|
|
# The subclasses for OGR Geometry.
|
|
class Point(OGRGeometry):
|
|
|
|
@property
|
|
def x(self):
|
|
"Returns the X coordinate for this Point."
|
|
return capi.getx(self.ptr, 0)
|
|
|
|
@property
|
|
def y(self):
|
|
"Returns the Y coordinate for this Point."
|
|
return capi.gety(self.ptr, 0)
|
|
|
|
@property
|
|
def z(self):
|
|
"Returns the Z coordinate for this Point."
|
|
if self.coord_dim == 3:
|
|
return capi.getz(self.ptr, 0)
|
|
|
|
@property
|
|
def tuple(self):
|
|
"Returns the tuple of this point."
|
|
if self.coord_dim == 2:
|
|
return (self.x, self.y)
|
|
elif self.coord_dim == 3:
|
|
return (self.x, self.y, self.z)
|
|
coords = tuple
|
|
|
|
|
|
class LineString(OGRGeometry):
|
|
|
|
def __getitem__(self, index):
|
|
"Returns the Point at the given index."
|
|
if index >= 0 and index < self.point_count:
|
|
x, y, z = c_double(), c_double(), c_double()
|
|
capi.get_point(self.ptr, index, byref(x), byref(y), byref(z))
|
|
dim = self.coord_dim
|
|
if dim == 1:
|
|
return (x.value,)
|
|
elif dim == 2:
|
|
return (x.value, y.value)
|
|
elif dim == 3:
|
|
return (x.value, y.value, z.value)
|
|
else:
|
|
raise OGRIndexError('index out of range: %s' % str(index))
|
|
|
|
def __iter__(self):
|
|
"Iterates over each point in the LineString."
|
|
for i in range(self.point_count):
|
|
yield self[i]
|
|
|
|
def __len__(self):
|
|
"The length returns the number of points in the LineString."
|
|
return self.point_count
|
|
|
|
@property
|
|
def tuple(self):
|
|
"Returns the tuple representation of this LineString."
|
|
return tuple(self[i] for i in range(len(self)))
|
|
coords = tuple
|
|
|
|
def _listarr(self, func):
|
|
"""
|
|
Internal routine that returns a sequence (list) corresponding with
|
|
the given function.
|
|
"""
|
|
return [func(self.ptr, i) for i in range(len(self))]
|
|
|
|
@property
|
|
def x(self):
|
|
"Returns the X coordinates in a list."
|
|
return self._listarr(capi.getx)
|
|
|
|
@property
|
|
def y(self):
|
|
"Returns the Y coordinates in a list."
|
|
return self._listarr(capi.gety)
|
|
|
|
@property
|
|
def z(self):
|
|
"Returns the Z coordinates in a list."
|
|
if self.coord_dim == 3:
|
|
return self._listarr(capi.getz)
|
|
|
|
|
|
# LinearRings are used in Polygons.
|
|
class LinearRing(LineString):
|
|
pass
|
|
|
|
|
|
class Polygon(OGRGeometry):
|
|
|
|
def __len__(self):
|
|
"The number of interior rings in this Polygon."
|
|
return self.geom_count
|
|
|
|
def __iter__(self):
|
|
"Iterates through each ring in the Polygon."
|
|
for i in range(self.geom_count):
|
|
yield self[i]
|
|
|
|
def __getitem__(self, index):
|
|
"Gets the ring at the specified index."
|
|
if index < 0 or index >= self.geom_count:
|
|
raise OGRIndexError('index out of range: %s' % index)
|
|
else:
|
|
return OGRGeometry(capi.clone_geom(capi.get_geom_ref(self.ptr, index)), self.srs)
|
|
|
|
# Polygon Properties
|
|
@property
|
|
def shell(self):
|
|
"Returns the shell of this Polygon."
|
|
return self[0] # First ring is the shell
|
|
exterior_ring = shell
|
|
|
|
@property
|
|
def tuple(self):
|
|
"Returns a tuple of LinearRing coordinate tuples."
|
|
return tuple(self[i].tuple for i in range(self.geom_count))
|
|
coords = tuple
|
|
|
|
@property
|
|
def point_count(self):
|
|
"The number of Points in this Polygon."
|
|
# Summing up the number of points in each ring of the Polygon.
|
|
return sum(self[i].point_count for i in range(self.geom_count))
|
|
|
|
@property
|
|
def centroid(self):
|
|
"Returns the centroid (a Point) of this Polygon."
|
|
# The centroid is a Point, create a geometry for this.
|
|
p = OGRGeometry(OGRGeomType('Point'))
|
|
capi.get_centroid(self.ptr, p.ptr)
|
|
return p
|
|
|
|
|
|
# Geometry Collection base class.
|
|
class GeometryCollection(OGRGeometry):
|
|
"The Geometry Collection class."
|
|
|
|
def __getitem__(self, index):
|
|
"Gets the Geometry at the specified index."
|
|
if index < 0 or index >= self.geom_count:
|
|
raise OGRIndexError('index out of range: %s' % index)
|
|
else:
|
|
return OGRGeometry(capi.clone_geom(capi.get_geom_ref(self.ptr, index)), self.srs)
|
|
|
|
def __iter__(self):
|
|
"Iterates over each Geometry."
|
|
for i in range(self.geom_count):
|
|
yield self[i]
|
|
|
|
def __len__(self):
|
|
"The number of geometries in this Geometry Collection."
|
|
return self.geom_count
|
|
|
|
def add(self, geom):
|
|
"Add the geometry to this Geometry Collection."
|
|
if isinstance(geom, OGRGeometry):
|
|
if isinstance(geom, self.__class__):
|
|
for g in geom:
|
|
capi.add_geom(self.ptr, g.ptr)
|
|
else:
|
|
capi.add_geom(self.ptr, geom.ptr)
|
|
elif isinstance(geom, six.string_types):
|
|
tmp = OGRGeometry(geom)
|
|
capi.add_geom(self.ptr, tmp.ptr)
|
|
else:
|
|
raise GDALException('Must add an OGRGeometry.')
|
|
|
|
@property
|
|
def point_count(self):
|
|
"The number of Points in this Geometry Collection."
|
|
# Summing up the number of points in each geometry in this collection
|
|
return sum(self[i].point_count for i in range(self.geom_count))
|
|
|
|
@property
|
|
def tuple(self):
|
|
"Returns a tuple representation of this Geometry Collection."
|
|
return tuple(self[i].tuple for i in range(self.geom_count))
|
|
coords = tuple
|
|
|
|
|
|
# Multiple Geometry types.
|
|
class MultiPoint(GeometryCollection):
|
|
pass
|
|
|
|
|
|
class MultiLineString(GeometryCollection):
|
|
pass
|
|
|
|
|
|
class MultiPolygon(GeometryCollection):
|
|
pass
|
|
|
|
|
|
# Class mapping dictionary (using the OGRwkbGeometryType as the key)
|
|
GEO_CLASSES = {1: Point,
|
|
2: LineString,
|
|
3: Polygon,
|
|
4: MultiPoint,
|
|
5: MultiLineString,
|
|
6: MultiPolygon,
|
|
7: GeometryCollection,
|
|
101: LinearRing,
|
|
1 + OGRGeomType.wkb25bit: Point,
|
|
2 + OGRGeomType.wkb25bit: LineString,
|
|
3 + OGRGeomType.wkb25bit: Polygon,
|
|
4 + OGRGeomType.wkb25bit: MultiPoint,
|
|
5 + OGRGeomType.wkb25bit: MultiLineString,
|
|
6 + OGRGeomType.wkb25bit: MultiPolygon,
|
|
7 + OGRGeomType.wkb25bit: GeometryCollection,
|
|
}
|