723 lines
26 KiB
Python
723 lines
26 KiB
Python
"""
|
|
This module contains the 'base' GEOSGeometry object -- all GEOS Geometries
|
|
inherit from this object.
|
|
"""
|
|
from __future__ import unicode_literals
|
|
|
|
# Python, ctypes and types dependencies.
|
|
from ctypes import addressof, byref, c_double
|
|
|
|
from django.contrib.gis import memoryview
|
|
# super-class for mutable list behavior
|
|
from django.contrib.gis.geos.mutable_list import ListMixin
|
|
|
|
from django.contrib.gis.gdal.error import SRSException
|
|
|
|
# GEOS-related dependencies.
|
|
from django.contrib.gis.geos.base import GEOSBase, gdal
|
|
from django.contrib.gis.geos.coordseq import GEOSCoordSeq
|
|
from django.contrib.gis.geos.error import GEOSException, GEOSIndexError
|
|
from django.contrib.gis.geos.libgeos import GEOM_PTR, GEOS_PREPARE
|
|
|
|
# All other functions in this module come from the ctypes
|
|
# prototypes module -- which handles all interaction with
|
|
# the underlying GEOS library.
|
|
from django.contrib.gis.geos import prototypes as capi
|
|
|
|
# These functions provide access to a thread-local instance
|
|
# of their corresponding GEOS I/O class.
|
|
from django.contrib.gis.geos.prototypes.io import wkt_r, wkt_w, wkb_r, wkb_w, ewkb_w
|
|
|
|
# For recognizing geometry input.
|
|
from django.contrib.gis.geometry.regex import hex_regex, wkt_regex, json_regex
|
|
|
|
from django.utils import six
|
|
from django.utils.encoding import force_bytes, force_text
|
|
|
|
|
|
class GEOSGeometry(GEOSBase, ListMixin):
|
|
"A class that, generally, encapsulates a GEOS geometry."
|
|
|
|
# Raise GEOSIndexError instead of plain IndexError
|
|
# (see ticket #4740 and GEOSIndexError docstring)
|
|
_IndexError = GEOSIndexError
|
|
|
|
ptr_type = GEOM_PTR
|
|
|
|
#### Python 'magic' routines ####
|
|
def __init__(self, geo_input, srid=None):
|
|
"""
|
|
The base constructor for GEOS geometry objects, and may take the
|
|
following inputs:
|
|
|
|
* strings:
|
|
- WKT
|
|
- HEXEWKB (a PostGIS-specific canonical form)
|
|
- GeoJSON (requires GDAL)
|
|
* buffer:
|
|
- WKB
|
|
|
|
The `srid` keyword is used to specify the Source Reference Identifier
|
|
(SRID) number for this Geometry. If not set, the SRID will be None.
|
|
"""
|
|
if isinstance(geo_input, bytes):
|
|
geo_input = force_text(geo_input)
|
|
if isinstance(geo_input, six.string_types):
|
|
wkt_m = wkt_regex.match(geo_input)
|
|
if wkt_m:
|
|
# Handling WKT input.
|
|
if wkt_m.group('srid'):
|
|
srid = int(wkt_m.group('srid'))
|
|
g = wkt_r().read(force_bytes(wkt_m.group('wkt')))
|
|
elif hex_regex.match(geo_input):
|
|
# Handling HEXEWKB input.
|
|
g = wkb_r().read(force_bytes(geo_input))
|
|
elif gdal.HAS_GDAL and json_regex.match(geo_input):
|
|
# Handling GeoJSON input.
|
|
g = wkb_r().read(gdal.OGRGeometry(geo_input).wkb)
|
|
else:
|
|
raise ValueError('String or unicode input unrecognized as WKT EWKT, and HEXEWKB.')
|
|
elif isinstance(geo_input, GEOM_PTR):
|
|
# When the input is a pointer to a geomtry (GEOM_PTR).
|
|
g = geo_input
|
|
elif isinstance(geo_input, memoryview):
|
|
# When the input is a buffer (WKB).
|
|
g = wkb_r().read(geo_input)
|
|
elif isinstance(geo_input, GEOSGeometry):
|
|
g = capi.geom_clone(geo_input.ptr)
|
|
else:
|
|
# Invalid geometry type.
|
|
raise TypeError('Improper geometry input type: %s' % str(type(geo_input)))
|
|
|
|
if g:
|
|
# Setting the pointer object with a valid pointer.
|
|
self.ptr = g
|
|
else:
|
|
raise GEOSException('Could not initialize GEOS Geometry with given input.')
|
|
|
|
# Post-initialization setup.
|
|
self._post_init(srid)
|
|
|
|
def _post_init(self, srid):
|
|
"Helper routine for performing post-initialization setup."
|
|
# Setting the SRID, if given.
|
|
if srid and isinstance(srid, int):
|
|
self.srid = srid
|
|
|
|
# Setting the class type (e.g., Point, Polygon, etc.)
|
|
self.__class__ = GEOS_CLASSES[self.geom_typeid]
|
|
|
|
# Setting the coordinate sequence for the geometry (will be None on
|
|
# geometries that do not have coordinate sequences)
|
|
self._set_cs()
|
|
|
|
def __del__(self):
|
|
"""
|
|
Destroys this Geometry; in other words, frees the memory used by the
|
|
GEOS C++ object.
|
|
"""
|
|
if self._ptr:
|
|
capi.destroy_geom(self._ptr)
|
|
|
|
def __copy__(self):
|
|
"""
|
|
Returns a clone because the copy of a GEOSGeometry may contain an
|
|
invalid pointer location if the original is garbage collected.
|
|
"""
|
|
return self.clone()
|
|
|
|
def __deepcopy__(self, memodict):
|
|
"""
|
|
The `deepcopy` routine is used by the `Node` class of django.utils.tree;
|
|
thus, the protocol routine needs to be implemented to return correct
|
|
copies (clones) of these GEOS objects, which use C pointers.
|
|
"""
|
|
return self.clone()
|
|
|
|
def __str__(self):
|
|
"WKT is used for the string representation."
|
|
return self.wkt
|
|
|
|
def __repr__(self):
|
|
"Short-hand representation because WKT may be very large."
|
|
return '<%s object at %s>' % (self.geom_type, hex(addressof(self.ptr)))
|
|
|
|
# Pickling support
|
|
def __getstate__(self):
|
|
# The pickled state is simply a tuple of the WKB (in string form)
|
|
# and the SRID.
|
|
return bytes(self.wkb), self.srid
|
|
|
|
def __setstate__(self, state):
|
|
# Instantiating from the tuple state that was pickled.
|
|
wkb, srid = state
|
|
ptr = wkb_r().read(memoryview(wkb))
|
|
if not ptr:
|
|
raise GEOSException('Invalid Geometry loaded from pickled state.')
|
|
self.ptr = ptr
|
|
self._post_init(srid)
|
|
|
|
# Comparison operators
|
|
def __eq__(self, other):
|
|
"""
|
|
Equivalence testing, a Geometry may be compared with another Geometry
|
|
or a WKT representation.
|
|
"""
|
|
if isinstance(other, six.string_types):
|
|
return self.wkt == other
|
|
elif isinstance(other, GEOSGeometry):
|
|
return self.equals_exact(other)
|
|
else:
|
|
return False
|
|
|
|
def __ne__(self, other):
|
|
"The not equals operator."
|
|
return not (self == other)
|
|
|
|
### Geometry set-like operations ###
|
|
# Thanks to Sean Gillies for inspiration:
|
|
# http://lists.gispython.org/pipermail/community/2007-July/001034.html
|
|
# g = g1 | g2
|
|
def __or__(self, other):
|
|
"Returns the union of this Geometry and the other."
|
|
return self.union(other)
|
|
|
|
# g = g1 & g2
|
|
def __and__(self, other):
|
|
"Returns the intersection of this Geometry and the other."
|
|
return self.intersection(other)
|
|
|
|
# g = g1 - g2
|
|
def __sub__(self, other):
|
|
"Return the difference this Geometry and the other."
|
|
return self.difference(other)
|
|
|
|
# g = g1 ^ g2
|
|
def __xor__(self, other):
|
|
"Return the symmetric difference of this Geometry and the other."
|
|
return self.sym_difference(other)
|
|
|
|
#### Coordinate Sequence Routines ####
|
|
@property
|
|
def has_cs(self):
|
|
"Returns True if this Geometry has a coordinate sequence, False if not."
|
|
# Only these geometries are allowed to have coordinate sequences.
|
|
if isinstance(self, (Point, LineString, LinearRing)):
|
|
return True
|
|
else:
|
|
return False
|
|
|
|
def _set_cs(self):
|
|
"Sets the coordinate sequence for this Geometry."
|
|
if self.has_cs:
|
|
self._cs = GEOSCoordSeq(capi.get_cs(self.ptr), self.hasz)
|
|
else:
|
|
self._cs = None
|
|
|
|
@property
|
|
def coord_seq(self):
|
|
"Returns a clone of the coordinate sequence for this Geometry."
|
|
if self.has_cs:
|
|
return self._cs.clone()
|
|
|
|
#### Geometry Info ####
|
|
@property
|
|
def geom_type(self):
|
|
"Returns a string representing the Geometry type, e.g. 'Polygon'"
|
|
return capi.geos_type(self.ptr).decode()
|
|
|
|
@property
|
|
def geom_typeid(self):
|
|
"Returns an integer representing the Geometry type."
|
|
return capi.geos_typeid(self.ptr)
|
|
|
|
@property
|
|
def num_geom(self):
|
|
"Returns the number of geometries in the Geometry."
|
|
return capi.get_num_geoms(self.ptr)
|
|
|
|
@property
|
|
def num_coords(self):
|
|
"Returns the number of coordinates in the Geometry."
|
|
return capi.get_num_coords(self.ptr)
|
|
|
|
@property
|
|
def num_points(self):
|
|
"Returns the number points, or coordinates, in the Geometry."
|
|
return self.num_coords
|
|
|
|
@property
|
|
def dims(self):
|
|
"Returns the dimension of this Geometry (0=point, 1=line, 2=surface)."
|
|
return capi.get_dims(self.ptr)
|
|
|
|
def normalize(self):
|
|
"Converts this Geometry to normal form (or canonical form)."
|
|
return capi.geos_normalize(self.ptr)
|
|
|
|
#### Unary predicates ####
|
|
@property
|
|
def empty(self):
|
|
"""
|
|
Returns a boolean indicating whether the set of points in this Geometry
|
|
are empty.
|
|
"""
|
|
return capi.geos_isempty(self.ptr)
|
|
|
|
@property
|
|
def hasz(self):
|
|
"Returns whether the geometry has a 3D dimension."
|
|
return capi.geos_hasz(self.ptr)
|
|
|
|
@property
|
|
def ring(self):
|
|
"Returns whether or not the geometry is a ring."
|
|
return capi.geos_isring(self.ptr)
|
|
|
|
@property
|
|
def simple(self):
|
|
"Returns false if the Geometry not simple."
|
|
return capi.geos_issimple(self.ptr)
|
|
|
|
@property
|
|
def valid(self):
|
|
"This property tests the validity of this Geometry."
|
|
return capi.geos_isvalid(self.ptr)
|
|
|
|
@property
|
|
def valid_reason(self):
|
|
"""
|
|
Returns a string containing the reason for any invalidity.
|
|
"""
|
|
if not GEOS_PREPARE:
|
|
raise GEOSException('Upgrade GEOS to 3.1 to get validity reason.')
|
|
return capi.geos_isvalidreason(self.ptr).decode()
|
|
|
|
#### Binary predicates. ####
|
|
def contains(self, other):
|
|
"Returns true if other.within(this) returns true."
|
|
return capi.geos_contains(self.ptr, other.ptr)
|
|
|
|
def crosses(self, other):
|
|
"""
|
|
Returns true if the DE-9IM intersection matrix for the two Geometries
|
|
is T*T****** (for a point and a curve,a point and an area or a line and
|
|
an area) 0******** (for two curves).
|
|
"""
|
|
return capi.geos_crosses(self.ptr, other.ptr)
|
|
|
|
def disjoint(self, other):
|
|
"""
|
|
Returns true if the DE-9IM intersection matrix for the two Geometries
|
|
is FF*FF****.
|
|
"""
|
|
return capi.geos_disjoint(self.ptr, other.ptr)
|
|
|
|
def equals(self, other):
|
|
"""
|
|
Returns true if the DE-9IM intersection matrix for the two Geometries
|
|
is T*F**FFF*.
|
|
"""
|
|
return capi.geos_equals(self.ptr, other.ptr)
|
|
|
|
def equals_exact(self, other, tolerance=0):
|
|
"""
|
|
Returns true if the two Geometries are exactly equal, up to a
|
|
specified tolerance.
|
|
"""
|
|
return capi.geos_equalsexact(self.ptr, other.ptr, float(tolerance))
|
|
|
|
def intersects(self, other):
|
|
"Returns true if disjoint returns false."
|
|
return capi.geos_intersects(self.ptr, other.ptr)
|
|
|
|
def overlaps(self, other):
|
|
"""
|
|
Returns true if the DE-9IM intersection matrix for the two Geometries
|
|
is T*T***T** (for two points or two surfaces) 1*T***T** (for two curves).
|
|
"""
|
|
return capi.geos_overlaps(self.ptr, other.ptr)
|
|
|
|
def relate_pattern(self, other, pattern):
|
|
"""
|
|
Returns true if the elements in the DE-9IM intersection matrix for the
|
|
two Geometries match the elements in pattern.
|
|
"""
|
|
if not isinstance(pattern, six.string_types) or len(pattern) > 9:
|
|
raise GEOSException('invalid intersection matrix pattern')
|
|
return capi.geos_relatepattern(self.ptr, other.ptr, force_bytes(pattern))
|
|
|
|
def touches(self, other):
|
|
"""
|
|
Returns true if the DE-9IM intersection matrix for the two Geometries
|
|
is FT*******, F**T***** or F***T****.
|
|
"""
|
|
return capi.geos_touches(self.ptr, other.ptr)
|
|
|
|
def within(self, other):
|
|
"""
|
|
Returns true if the DE-9IM intersection matrix for the two Geometries
|
|
is T*F**F***.
|
|
"""
|
|
return capi.geos_within(self.ptr, other.ptr)
|
|
|
|
#### SRID Routines ####
|
|
def get_srid(self):
|
|
"Gets the SRID for the geometry, returns None if no SRID is set."
|
|
s = capi.geos_get_srid(self.ptr)
|
|
if s == 0:
|
|
return None
|
|
else:
|
|
return s
|
|
|
|
def set_srid(self, srid):
|
|
"Sets the SRID for the geometry."
|
|
capi.geos_set_srid(self.ptr, srid)
|
|
srid = property(get_srid, set_srid)
|
|
|
|
#### Output Routines ####
|
|
@property
|
|
def ewkt(self):
|
|
"""
|
|
Returns the EWKT (WKT + SRID) of the Geometry. Note that Z values
|
|
are *not* included in this representation because GEOS does not yet
|
|
support serializing them.
|
|
"""
|
|
if self.get_srid():
|
|
return 'SRID=%s;%s' % (self.srid, self.wkt)
|
|
else:
|
|
return self.wkt
|
|
|
|
@property
|
|
def wkt(self):
|
|
"Returns the WKT (Well-Known Text) representation of this Geometry."
|
|
return wkt_w(3 if self.hasz else 2).write(self).decode()
|
|
|
|
@property
|
|
def hex(self):
|
|
"""
|
|
Returns the WKB of this Geometry in hexadecimal form. Please note
|
|
that the SRID is not included in this representation because it is not
|
|
a part of the OGC specification (use the `hexewkb` property instead).
|
|
"""
|
|
# A possible faster, all-python, implementation:
|
|
# str(self.wkb).encode('hex')
|
|
return wkb_w(3 if self.hasz else 2).write_hex(self)
|
|
|
|
@property
|
|
def hexewkb(self):
|
|
"""
|
|
Returns the EWKB of this Geometry in hexadecimal form. This is an
|
|
extension of the WKB specification that includes SRID value that are
|
|
a part of this geometry.
|
|
"""
|
|
if self.hasz and not GEOS_PREPARE:
|
|
# See: http://trac.osgeo.org/geos/ticket/216
|
|
raise GEOSException('Upgrade GEOS to 3.1 to get valid 3D HEXEWKB.')
|
|
return ewkb_w(3 if self.hasz else 2).write_hex(self)
|
|
|
|
@property
|
|
def json(self):
|
|
"""
|
|
Returns GeoJSON representation of this Geometry if GDAL is installed.
|
|
"""
|
|
if gdal.HAS_GDAL:
|
|
return self.ogr.json
|
|
else:
|
|
raise GEOSException('GeoJSON output only supported when GDAL is installed.')
|
|
geojson = json
|
|
|
|
@property
|
|
def wkb(self):
|
|
"""
|
|
Returns the WKB (Well-Known Binary) representation of this Geometry
|
|
as a Python buffer. SRID and Z values are not included, use the
|
|
`ewkb` property instead.
|
|
"""
|
|
return wkb_w(3 if self.hasz else 2).write(self)
|
|
|
|
@property
|
|
def ewkb(self):
|
|
"""
|
|
Return the EWKB representation of this Geometry as a Python buffer.
|
|
This is an extension of the WKB specification that includes any SRID
|
|
value that are a part of this geometry.
|
|
"""
|
|
if self.hasz and not GEOS_PREPARE:
|
|
# See: http://trac.osgeo.org/geos/ticket/216
|
|
raise GEOSException('Upgrade GEOS to 3.1 to get valid 3D EWKB.')
|
|
return ewkb_w(3 if self.hasz else 2).write(self)
|
|
|
|
@property
|
|
def kml(self):
|
|
"Returns the KML representation of this Geometry."
|
|
gtype = self.geom_type
|
|
return '<%s>%s</%s>' % (gtype, self.coord_seq.kml, gtype)
|
|
|
|
@property
|
|
def prepared(self):
|
|
"""
|
|
Returns a PreparedGeometry corresponding to this geometry -- it is
|
|
optimized for the contains, intersects, and covers operations.
|
|
"""
|
|
if GEOS_PREPARE:
|
|
return PreparedGeometry(self)
|
|
else:
|
|
raise GEOSException('GEOS 3.1+ required for prepared geometry support.')
|
|
|
|
#### GDAL-specific output routines ####
|
|
@property
|
|
def ogr(self):
|
|
"Returns the OGR Geometry for this Geometry."
|
|
if not gdal.HAS_GDAL:
|
|
raise GEOSException('GDAL required to convert to an OGRGeometry.')
|
|
if self.srid:
|
|
try:
|
|
return gdal.OGRGeometry(self.wkb, self.srid)
|
|
except SRSException:
|
|
pass
|
|
return gdal.OGRGeometry(self.wkb)
|
|
|
|
@property
|
|
def srs(self):
|
|
"Returns the OSR SpatialReference for SRID of this Geometry."
|
|
if not gdal.HAS_GDAL:
|
|
raise GEOSException('GDAL required to return a SpatialReference object.')
|
|
if self.srid:
|
|
try:
|
|
return gdal.SpatialReference(self.srid)
|
|
except SRSException:
|
|
pass
|
|
return None
|
|
|
|
@property
|
|
def crs(self):
|
|
"Alias for `srs` property."
|
|
return self.srs
|
|
|
|
def transform(self, ct, clone=False):
|
|
"""
|
|
Requires GDAL. Transforms the geometry according to the given
|
|
transformation object, which may be an integer SRID, and WKT or
|
|
PROJ.4 string. By default, the geometry is transformed in-place and
|
|
nothing is returned. However if the `clone` keyword is set, then this
|
|
geometry will not be modified and a transformed clone will be returned
|
|
instead.
|
|
"""
|
|
srid = self.srid
|
|
|
|
if ct == srid:
|
|
# short-circuit where source & dest SRIDs match
|
|
if clone:
|
|
return self.clone()
|
|
else:
|
|
return
|
|
|
|
if (srid is None) or (srid < 0):
|
|
raise GEOSException("Calling transform() with no SRID set is not supported")
|
|
|
|
if not gdal.HAS_GDAL:
|
|
raise GEOSException("GDAL library is not available to transform() geometry.")
|
|
|
|
# Creating an OGR Geometry, which is then transformed.
|
|
g = self.ogr
|
|
g.transform(ct)
|
|
# Getting a new GEOS pointer
|
|
ptr = wkb_r().read(g.wkb)
|
|
if clone:
|
|
# User wants a cloned transformed geometry returned.
|
|
return GEOSGeometry(ptr, srid=g.srid)
|
|
if ptr:
|
|
# Reassigning pointer, and performing post-initialization setup
|
|
# again due to the reassignment.
|
|
capi.destroy_geom(self.ptr)
|
|
self.ptr = ptr
|
|
self._post_init(g.srid)
|
|
else:
|
|
raise GEOSException('Transformed WKB was invalid.')
|
|
|
|
#### Topology Routines ####
|
|
def _topology(self, gptr):
|
|
"Helper routine to return Geometry from the given pointer."
|
|
return GEOSGeometry(gptr, srid=self.srid)
|
|
|
|
@property
|
|
def boundary(self):
|
|
"Returns the boundary as a newly allocated Geometry object."
|
|
return self._topology(capi.geos_boundary(self.ptr))
|
|
|
|
def buffer(self, width, quadsegs=8):
|
|
"""
|
|
Returns a geometry that represents all points whose distance from this
|
|
Geometry is less than or equal to distance. Calculations are in the
|
|
Spatial Reference System of this Geometry. The optional third parameter sets
|
|
the number of segment used to approximate a quarter circle (defaults to 8).
|
|
(Text from PostGIS documentation at ch. 6.1.3)
|
|
"""
|
|
return self._topology(capi.geos_buffer(self.ptr, width, quadsegs))
|
|
|
|
@property
|
|
def centroid(self):
|
|
"""
|
|
The centroid is equal to the centroid of the set of component Geometries
|
|
of highest dimension (since the lower-dimension geometries contribute zero
|
|
"weight" to the centroid).
|
|
"""
|
|
return self._topology(capi.geos_centroid(self.ptr))
|
|
|
|
@property
|
|
def convex_hull(self):
|
|
"""
|
|
Returns the smallest convex Polygon that contains all the points
|
|
in the Geometry.
|
|
"""
|
|
return self._topology(capi.geos_convexhull(self.ptr))
|
|
|
|
def difference(self, other):
|
|
"""
|
|
Returns a Geometry representing the points making up this Geometry
|
|
that do not make up other.
|
|
"""
|
|
return self._topology(capi.geos_difference(self.ptr, other.ptr))
|
|
|
|
@property
|
|
def envelope(self):
|
|
"Return the envelope for this geometry (a polygon)."
|
|
return self._topology(capi.geos_envelope(self.ptr))
|
|
|
|
def interpolate(self, distance):
|
|
if not isinstance(self, (LineString, MultiLineString)):
|
|
raise TypeError('interpolate only works on LineString and MultiLineString geometries')
|
|
if not hasattr(capi, 'geos_interpolate'):
|
|
raise NotImplementedError('interpolate requires GEOS 3.2+')
|
|
return self._topology(capi.geos_interpolate(self.ptr, distance))
|
|
|
|
def interpolate_normalized(self, distance):
|
|
if not isinstance(self, (LineString, MultiLineString)):
|
|
raise TypeError('interpolate only works on LineString and MultiLineString geometries')
|
|
if not hasattr(capi, 'geos_interpolate_normalized'):
|
|
raise NotImplementedError('interpolate_normalized requires GEOS 3.2+')
|
|
return self._topology(capi.geos_interpolate_normalized(self.ptr, distance))
|
|
|
|
def intersection(self, other):
|
|
"Returns a Geometry representing the points shared by this Geometry and other."
|
|
return self._topology(capi.geos_intersection(self.ptr, other.ptr))
|
|
|
|
@property
|
|
def point_on_surface(self):
|
|
"Computes an interior point of this Geometry."
|
|
return self._topology(capi.geos_pointonsurface(self.ptr))
|
|
|
|
def project(self, point):
|
|
if not isinstance(point, Point):
|
|
raise TypeError('locate_point argument must be a Point')
|
|
if not isinstance(self, (LineString, MultiLineString)):
|
|
raise TypeError('locate_point only works on LineString and MultiLineString geometries')
|
|
if not hasattr(capi, 'geos_project'):
|
|
raise NotImplementedError('geos_project requires GEOS 3.2+')
|
|
return capi.geos_project(self.ptr, point.ptr)
|
|
|
|
def project_normalized(self, point):
|
|
if not isinstance(point, Point):
|
|
raise TypeError('locate_point argument must be a Point')
|
|
if not isinstance(self, (LineString, MultiLineString)):
|
|
raise TypeError('locate_point only works on LineString and MultiLineString geometries')
|
|
if not hasattr(capi, 'geos_project_normalized'):
|
|
raise NotImplementedError('project_normalized requires GEOS 3.2+')
|
|
return capi.geos_project_normalized(self.ptr, point.ptr)
|
|
|
|
def relate(self, other):
|
|
"Returns the DE-9IM intersection matrix for this Geometry and the other."
|
|
return capi.geos_relate(self.ptr, other.ptr).decode()
|
|
|
|
def simplify(self, tolerance=0.0, preserve_topology=False):
|
|
"""
|
|
Returns the Geometry, simplified using the Douglas-Peucker algorithm
|
|
to the specified tolerance (higher tolerance => less points). If no
|
|
tolerance provided, defaults to 0.
|
|
|
|
By default, this function does not preserve topology - e.g. polygons can
|
|
be split, collapse to lines or disappear holes can be created or
|
|
disappear, and lines can cross. By specifying preserve_topology=True,
|
|
the result will have the same dimension and number of components as the
|
|
input. This is significantly slower.
|
|
"""
|
|
if preserve_topology:
|
|
return self._topology(capi.geos_preservesimplify(self.ptr, tolerance))
|
|
else:
|
|
return self._topology(capi.geos_simplify(self.ptr, tolerance))
|
|
|
|
def sym_difference(self, other):
|
|
"""
|
|
Returns a set combining the points in this Geometry not in other,
|
|
and the points in other not in this Geometry.
|
|
"""
|
|
return self._topology(capi.geos_symdifference(self.ptr, other.ptr))
|
|
|
|
def union(self, other):
|
|
"Returns a Geometry representing all the points in this Geometry and other."
|
|
return self._topology(capi.geos_union(self.ptr, other.ptr))
|
|
|
|
#### Other Routines ####
|
|
@property
|
|
def area(self):
|
|
"Returns the area of the Geometry."
|
|
return capi.geos_area(self.ptr, byref(c_double()))
|
|
|
|
def distance(self, other):
|
|
"""
|
|
Returns the distance between the closest points on this Geometry
|
|
and the other. Units will be in those of the coordinate system of
|
|
the Geometry.
|
|
"""
|
|
if not isinstance(other, GEOSGeometry):
|
|
raise TypeError('distance() works only on other GEOS Geometries.')
|
|
return capi.geos_distance(self.ptr, other.ptr, byref(c_double()))
|
|
|
|
@property
|
|
def extent(self):
|
|
"""
|
|
Returns the extent of this geometry as a 4-tuple, consisting of
|
|
(xmin, ymin, xmax, ymax).
|
|
"""
|
|
env = self.envelope
|
|
if isinstance(env, Point):
|
|
xmin, ymin = env.tuple
|
|
xmax, ymax = xmin, ymin
|
|
else:
|
|
xmin, ymin = env[0][0]
|
|
xmax, ymax = env[0][2]
|
|
return (xmin, ymin, xmax, ymax)
|
|
|
|
@property
|
|
def length(self):
|
|
"""
|
|
Returns the length of this Geometry (e.g., 0 for point, or the
|
|
circumfrence of a Polygon).
|
|
"""
|
|
return capi.geos_length(self.ptr, byref(c_double()))
|
|
|
|
def clone(self):
|
|
"Clones this Geometry."
|
|
return GEOSGeometry(capi.geom_clone(self.ptr), srid=self.srid)
|
|
|
|
# Class mapping dictionary. Has to be at the end to avoid import
|
|
# conflicts with GEOSGeometry.
|
|
from django.contrib.gis.geos.linestring import LineString, LinearRing
|
|
from django.contrib.gis.geos.point import Point
|
|
from django.contrib.gis.geos.polygon import Polygon
|
|
from django.contrib.gis.geos.collections import GeometryCollection, MultiPoint, MultiLineString, MultiPolygon
|
|
GEOS_CLASSES = {0: Point,
|
|
1: LineString,
|
|
2: LinearRing,
|
|
3: Polygon,
|
|
4: MultiPoint,
|
|
5: MultiLineString,
|
|
6: MultiPolygon,
|
|
7: GeometryCollection,
|
|
}
|
|
|
|
# If supported, import the PreparedGeometry class.
|
|
if GEOS_PREPARE:
|
|
from django.contrib.gis.geos.prepared import PreparedGeometry
|