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, six.string_types):
if isinstance(geo_input, six.text_type):
# Encoding to ASCII, WKT or HEXEWKB doesn't need any more.
geo_input = geo_input.encode('ascii')
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(wkt_m.group('wkt'))
elif hex_regex.match(geo_input):
# Handling HEXEWKB input.
g = wkb_r().read(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, buffer):
# 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 bool(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 djangocg.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 str(self.wkb), self.srid
def __setstate__(self, state):
# Instantiating from the tuple state that was pickled.
wkb, srid = state
ptr = wkb_r().read(buffer(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)
@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)
#### 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, 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().write(self)
@property
def hex(self):
"""
Returns the WKB of this Geometry in hexadecimal form. Please note
that the SRID and Z values are 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().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 and Z values
that are a part of this geometry.
"""
if self.hasz:
if 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_w3d().write_hex(self)
else:
return ewkb_w().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().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
and Z values that are a part of this geometry.
"""
if self.hasz:
if 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_w3d().write(self)
else:
return ewkb_w().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 gdal.HAS_GDAL:
if self.srid:
return gdal.OGRGeometry(self.wkb, self.srid)
else:
return gdal.OGRGeometry(self.wkb)
else:
raise GEOSException('GDAL required to convert to an OGRGeometry.')
@property
def srs(self):
"Returns the OSR SpatialReference for SRID of this Geometry."
if gdal.HAS_GDAL:
if self.srid:
return gdal.SpatialReference(self.srid)
else:
return None
else:
raise GEOSException('GDAL required to return a SpatialReference object.')
@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 = gdal.OGRGeometry(self.wkb, srid)
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 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 relate(self, other):
"Returns the DE-9IM intersection matrix for this Geometry and the other."
return capi.geos_relate(self.ptr, other.ptr)
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)
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
