GEOS stands for Geometry Engine  Open Source, and is a C++ library, ported from the Java Topology Suite. GEOS implements the OpenGIS Simple Features for SQL spatial predicate functions and spatial operators. GEOS, now an OSGeo project, was initially developed and maintained by Refractions Research of Victoria, Canada.
GeoDjango implements a highlevel Python wrapper for the GEOS library, its features include:
ctypes
.GEOSGeometry
objects may be used outside of a Django project/application. In other words, no need to have DJANGO_SETTINGS_MODULE
set or use a database, etc.GEOSGeometry
objects may be modified.This section contains a brief introduction and tutorial to using GEOSGeometry
objects.
GEOSGeometry
objects may be created in a few ways. The first is to simply instantiate the object on some spatial input – the following are examples of creating the same geometry from WKT, HEX, WKB, and GeoJSON:
>>> from django.contrib.gis.geos import GEOSGeometry >>> pnt = GEOSGeometry('POINT(5 23)') # WKT >>> pnt = GEOSGeometry('010100000000000000000014400000000000003740') # HEX >>> pnt = GEOSGeometry(buffer('\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x14@\x00\x00\x00\x00\x00\x007@')) >>> pnt = GEOSGeometry('{ "type": "Point", "coordinates": [ 5.000000, 23.000000 ] }') # GeoJSON
Another option is to use the constructor for the specific geometry type that you wish to create. For example, a Point
object may be created by passing in the X and Y coordinates into its constructor:
>>> from django.contrib.gis.geos import Point >>> pnt = Point(5, 23)
All these constructors take the keyword argument srid
. For example:
>>> from django.contrib.gis.geos import GEOSGeometry, LineString, Point >>> print(GEOSGeometry('POINT (0 0)', srid=4326)) SRID=4326;POINT (0 0) >>> print(LineString((0, 0), (1, 1), srid=4326)) SRID=4326;LINESTRING (0 0, 1 1) >>> print(Point(0, 0, srid=32140)) SRID=32140;POINT (0 0)
Finally, there is the fromfile()
factory method which returns a GEOSGeometry
object from a file:
>>> from django.contrib.gis.geos import fromfile >>> pnt = fromfile('/path/to/pnt.wkt') >>> pnt = fromfile(open('/path/to/pnt.wkt'))
GEOSGeometry
objects are ‘Pythonic’, in other words components may be accessed, modified, and iterated over using standard Python conventions. For example, you can iterate over the coordinates in a Point
:
>>> pnt = Point(5, 23) >>> [coord for coord in pnt] [5.0, 23.0]
With any geometry object, the GEOSGeometry.coords
property may be used to get the geometry coordinates as a Python tuple:
>>> pnt.coords (5.0, 23.0)
You can get/set geometry components using standard Python indexing techniques. However, what is returned depends on the geometry type of the object. For example, indexing on a LineString
returns a coordinate tuple:
>>> from django.contrib.gis.geos import LineString >>> line = LineString((0, 0), (0, 50), (50, 50), (50, 0), (0, 0)) >>> line[0] (0.0, 0.0) >>> line[2] (50.0, 0.0)
Whereas indexing on a Polygon
will return the ring (a LinearRing
object) corresponding to the index:
>>> from django.contrib.gis.geos import Polygon >>> poly = Polygon( ((0.0, 0.0), (0.0, 50.0), (50.0, 50.0), (50.0, 0.0), (0.0, 0.0)) ) >>> poly[0] <LinearRing object at 0x1044395b0> >>> poly[0][2] # secondtolast coordinate of external ring (50.0, 0.0)
In addition, coordinates/components of the geometry may added or modified, just like a Python list:
>>> line[0] = (1.0, 1.0) >>> line.pop() (0.0, 0.0) >>> line.append((1.0, 1.0)) >>> line.coords ((1.0, 1.0), (0.0, 50.0), (50.0, 50.0), (50.0, 0.0), (1.0, 1.0))
Geometries support setlike operators:
>>> from django.contrib.gis.geos import LineString >>> ls1 = LineString((0, 0), (2, 2)) >>> ls2 = LineString((1, 1), (3, 3)) >>> print(ls1  ls2) # equivalent to `ls1.union(ls2)` MULTILINESTRING ((0 0, 1 1), (1 1, 2 2), (2 2, 3 3)) >>> print(ls1 & ls2) # equivalent to `ls1.intersection(ls2)` LINESTRING (1 1, 2 2) >>> print(ls1  ls2) # equivalent to `ls1.difference(ls2)` LINESTRING(0 0, 1 1) >>> print(ls1 ^ ls2) # equivalent to `ls1.sym_difference(ls2)` MULTILINESTRING ((0 0, 1 1), (2 2, 3 3))
Equality operator doesn’t check spatial equality
The GEOSGeometry
equality operator uses equals_exact()
, not equals()
, i.e. it requires the compared geometries to have the same coordinates in the same positions with the same SRIDs:
>>> from django.contrib.gis.geos import LineString >>> ls1 = LineString((0, 0), (1, 1)) >>> ls2 = LineString((1, 1), (0, 0)) >>> ls3 = LineString((1, 1), (0, 0), srid=4326) >>> ls1.equals(ls2) True >>> ls1 == ls2 False >>> ls3 == ls2 # different SRIDs False
Older versions didn’t check the srid
when comparing GEOSGeometry
objects using the equality operator.
GEOSGeometry
class GEOSGeometry(geo_input, srid=None)
Parameters: 


This is the base class for all GEOS geometry objects. It initializes on the given geo_input
argument, and then assumes the proper geometry subclass (e.g., GEOSGeometry('POINT(1 1)')
will create a Point
object).
The following input formats, along with their corresponding Python types, are accepted:
Format  Input Type 

WKT / EWKT 
str or unicode

HEX / HEXEWKB 
str or unicode

WKB / EWKB  buffer 
GeoJSON 
str or unicode

classmethod GEOSGeometry.from_gml(gml_string)
Constructs a GEOSGeometry
from the given GML string.
GEOSGeometry.coords
Returns the coordinates of the geometry as a tuple.
GEOSGeometry.dims
Returns the dimension of the geometry:
0
for Point
s and MultiPoint
s1
for LineString
s and MultiLineString
s2
for Polygon
s and MultiPolygon
s1
for empty GeometryCollection
sGeometryCollection
sGEOSGeometry.empty
Returns whether or not the set of points in the geometry is empty.
GEOSGeometry.geom_type
Returns a string corresponding to the type of geometry. For example:
>>> pnt = GEOSGeometry('POINT(5 23)') >>> pnt.geom_type 'Point'
GEOSGeometry.geom_typeid
Returns the GEOS geometry type identification number. The following table shows the value for each geometry type:
Geometry  ID 

Point  0 
LineString  1 
LinearRing  2 
Polygon  3 
MultiPoint  4 
MultiLineString  5 
MultiPolygon  6 
GeometryCollection  7 
GEOSGeometry.num_coords
Returns the number of coordinates in the geometry.
GEOSGeometry.num_geom
Returns the number of geometries in this geometry. In other words, will return 1 on anything but geometry collections.
GEOSGeometry.hasz
Returns a boolean indicating whether the geometry is threedimensional.
GEOSGeometry.ring
Returns a boolean indicating whether the geometry is a LinearRing
.
GEOSGeometry.simple
Returns a boolean indicating whether the geometry is ‘simple’. A geometry is simple if and only if it does not intersect itself (except at boundary points). For example, a LineString
object is not simple if it intersects itself. Thus, LinearRing
and Polygon
objects are always simple because they do cannot intersect themselves, by definition.
GEOSGeometry.valid
Returns a boolean indicating whether the geometry is valid.
GEOSGeometry.valid_reason
Returns a string describing the reason why a geometry is invalid.
GEOSGeometry.srid
Property that may be used to retrieve or set the SRID associated with the geometry. For example:
>>> pnt = Point(5, 23) >>> print(pnt.srid) None >>> pnt.srid = 4326 >>> pnt.srid 4326
The properties in this section export the GEOSGeometry
object into a different. This output may be in the form of a string, buffer, or even another object.
GEOSGeometry.ewkt
Returns the “extended” WellKnown Text of the geometry. This representation is specific to PostGIS and is a superset of the OGC WKT standard. [1] Essentially the SRID is prepended to the WKT representation, for example SRID=4326;POINT(5 23)
.
Note
The output from this property does not include the 3dm, 3dz, and 4d information that PostGIS supports in its EWKT representations.
GEOSGeometry.hex
Returns the WKB of this Geometry in hexadecimal form. Please note that the SRID value is not included in this representation because it is not a part of the OGC specification (use the GEOSGeometry.hexewkb
property instead).
GEOSGeometry.hexewkb
Returns the EWKB of this Geometry in hexadecimal form. This is an extension of the WKB specification that includes the SRID value that are a part of this geometry.
GEOSGeometry.json
Returns the GeoJSON representation of the geometry. Note that the result is not a complete GeoJSON structure but only the geometry
key content of a GeoJSON structure. See also GeoJSON Serializer.
GEOSGeometry.geojson
Alias for GEOSGeometry.json
.
GEOSGeometry.kml
Returns a KML (Keyhole Markup Language) representation of the geometry. This should only be used for geometries with an SRID of 4326 (WGS84), but this restriction is not enforced.
GEOSGeometry.ogr
Returns an OGRGeometry
object corresponding to the GEOS geometry.
GEOSGeometry.wkb
Returns the WKB (WellKnown Binary) representation of this Geometry as a Python buffer. SRID value is not included, use the GEOSGeometry.ewkb
property instead.
GEOSGeometry.ewkb
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.
GEOSGeometry.wkt
Returns the WellKnown Text of the geometry (an OGC standard).
Nonsignificant zeros are stripped from the output.
All of the following spatial predicate methods take another GEOSGeometry
instance (other
) as a parameter, and return a boolean.
GEOSGeometry.contains(other)
Returns True
if other.within(this)
returns True
.
GEOSGeometry.covers(other)
Returns True
if this geometry covers the specified geometry.
The covers
predicate has the following equivalent definitions:
T*****FF*
, *T****FF*
, ***T**FF*
, or ****T*FF*
.If either geometry is empty, returns False
.
This predicate is similar to GEOSGeometry.contains()
, but is more inclusive (i.e. returns True
for more cases). In particular, unlike contains()
it does not distinguish between points in the boundary and in the interior of geometries. For most situations, covers()
should be preferred to contains()
. As an added benefit, covers()
is more amenable to optimization and hence should outperform contains()
.
GEOSGeometry.crosses(other)
Returns True
if the DE9IM 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).
GEOSGeometry.disjoint(other)
Returns True
if the DE9IM intersection matrix for the two geometries is FF*FF****
.
GEOSGeometry.equals(other)
Returns True
if the DE9IM intersection matrix for the two geometries is T*F**FFF*
.
GEOSGeometry.equals_exact(other, tolerance=0)
Returns true if the two geometries are exactly equal, up to a specified tolerance. The tolerance
value should be a floating point number representing the error tolerance in the comparison, e.g., poly1.equals_exact(poly2, 0.001)
will compare equality to within one thousandth of a unit.
GEOSGeometry.intersects(other)
Returns True
if GEOSGeometry.disjoint()
is False
.
GEOSGeometry.overlaps(other)
Returns true if the DE9IM intersection matrix for the two geometries is T*T***T**
(for two points or two surfaces) 1*T***T**
(for two curves).
GEOSGeometry.relate_pattern(other, pattern)
Returns True
if the elements in the DE9IM intersection matrix for this geometry and the other matches the given pattern
– a string of nine characters from the alphabet: {T
, F
, *
, 0
}.
GEOSGeometry.touches(other)
Returns True
if the DE9IM intersection matrix for the two geometries is FT*******
, F**T*****
or F***T****
.
GEOSGeometry.within(other)
Returns True
if the DE9IM intersection matrix for the two geometries is T*F**F***
.
GEOSGeometry.buffer(width, quadsegs=8)
Returns a GEOSGeometry
that represents all points whose distance from this geometry is less than or equal to the given width
. The optional quadsegs
keyword sets the number of segments used to approximate a quarter circle (defaults is 8).
GEOSGeometry.difference(other)
Returns a GEOSGeometry
representing the points making up this geometry that do not make up other.
GEOSGeometry.interpolate(distance)
GEOSGeometry.interpolate_normalized(distance)
Given a distance (float), returns the point (or closest point) within the geometry (LineString
or MultiLineString
) at that distance. The normalized version takes the distance as a float between 0 (origin) and 1 (endpoint).
Reverse of GEOSGeometry.project()
.
GEOSGeometry.intersection(other)
Returns a GEOSGeometry
representing the points shared by this geometry and other.
GEOSGeometry.project(point)
GEOSGeometry.project_normalized(point)
Returns the distance (float) from the origin of the geometry (LineString
or MultiLineString
) to the point projected on the geometry (that is to a point of the line the closest to the given point). The normalized version returns the distance as a float between 0 (origin) and 1 (endpoint).
Reverse of GEOSGeometry.interpolate()
.
GEOSGeometry.relate(other)
Returns the DE9IM intersection matrix (a string) representing the topological relationship between this geometry and the other.
GEOSGeometry.simplify(tolerance=0.0, preserve_topology=False)
Returns a new GEOSGeometry
, simplified to the specified tolerance using the DouglasPeucker algorithm. A higher tolerance value implies fewer points in the output. If no tolerance is provided, it defaults to 0.
By default, this function does not preserve topology. For example, Polygon
objects can be split, be collapsed into lines, or disappear. Polygon
holes can be created or disappear, and lines may cross. By specifying preserve_topology=True
, the result will have the same dimension and number of components as the input; this is significantly slower, however.
GEOSGeometry.sym_difference(other)
Returns a GEOSGeometry
combining the points in this geometry not in other, and the points in other not in this geometry.
GEOSGeometry.union(other)
Returns a GEOSGeometry
representing all the points in this geometry and the other.
GEOSGeometry.boundary
Returns the boundary as a newly allocated Geometry object.
GEOSGeometry.centroid
Returns a Point
object representing the geometric center of the geometry. The point is not guaranteed to be on the interior of the geometry.
GEOSGeometry.convex_hull
Returns the smallest Polygon
that contains all the points in the geometry.
GEOSGeometry.envelope
Returns a Polygon
that represents the bounding envelope of this geometry. Note that it can also return a Point
if the input geometry is a point.
GEOSGeometry.point_on_surface
Computes and returns a Point
guaranteed to be on the interior of this geometry.
GEOSGeometry.unary_union
Computes the union of all the elements of this geometry.
The result obeys the following contract:
LineString
s has the effect of fully noding and dissolving the linework.Polygon
s will always return a Polygon
or MultiPolygon
geometry (unlike GEOSGeometry.union()
, which may return geometries of lower dimension if a topology collapse occurs).GEOSGeometry.area
This property returns the area of the Geometry.
GEOSGeometry.extent
This property returns the extent of this geometry as a 4tuple, consisting of (xmin, ymin, xmax, ymax)
.
GEOSGeometry.clone()
This method returns a GEOSGeometry
that is a clone of the original.
GEOSGeometry.distance(geom)
Returns the distance between the closest points on this geometry and the given geom
(another GEOSGeometry
object).
Note
GEOS distance calculations are linear – in other words, GEOS does not perform a spherical calculation even if the SRID specifies a geographic coordinate system.
GEOSGeometry.length
Returns the length of this geometry (e.g., 0 for a Point
, the length of a LineString
, or the circumference of a Polygon
).
GEOSGeometry.prepared
Returns a GEOS PreparedGeometry
for the contents of this geometry. PreparedGeometry
objects are optimized for the contains, intersects, covers, crosses, disjoint, overlaps, touches and within operations. Refer to the Prepared Geometries documentation for more information.
GEOSGeometry.srs
Returns a SpatialReference
object corresponding to the SRID of the geometry or None
.
GEOSGeometry.transform(ct, clone=False)
Transforms the geometry according to the given coordinate transformation parameter (ct
), which may be an integer SRID, spatial reference WKT string, a PROJ.4 string, a SpatialReference
object, or a CoordTransform
object. By default, the geometry is transformed inplace and nothing is returned. However if the clone
keyword is set, then the geometry is not modified and a transformed clone of the geometry is returned instead.
Note
Raises GEOSException
if GDAL is not available or if the geometry’s SRID is None
or less than 0. It doesn’t impose any constraints on the geometry’s SRID if called with a CoordTransform
object.
In previous versions, it required the geometry’s SRID to be a positive integer even if it was called with a CoordTransform
object.
GEOSGeometry.normalize()
Converts this geometry to canonical form:
>>> g = MultiPoint(Point(0, 0), Point(2, 2), Point(1, 1)) >>> print(g) MULTIPOINT (0 0, 2 2, 1 1) >>> g.normalize() >>> print(g) MULTIPOINT (2 2, 1 1, 0 0)
Point
class Point(x=None, y=None, z=None, srid=None)
Point
objects are instantiated using arguments that represent the component coordinates of the point or with a single sequence coordinates. For example, the following are equivalent:
>>> pnt = Point(5, 23) >>> pnt = Point([5, 23])
Empty Point
objects may be instantiated by passing no arguments or an empty sequence. The following are equivalent:
>>> pnt = Point() >>> pnt = Point([])
In previous versions, an empty Point
couldn’t be instantiated.
LineString
class LineString(*args, **kwargs)
LineString
objects are instantiated using arguments that are either a sequence of coordinates or Point
objects. For example, the following are equivalent:
>>> ls = LineString((0, 0), (1, 1)) >>> ls = LineString(Point(0, 0), Point(1, 1))
In addition, LineString
objects may also be created by passing in a single sequence of coordinate or Point
objects:
>>> ls = LineString( ((0, 0), (1, 1)) ) >>> ls = LineString( [Point(0, 0), Point(1, 1)] )
Empty LineString
objects may be instantiated by passing no arguments or an empty sequence. The following are equivalent:
>>> ls = LineString() >>> ls = LineString([])
In previous versions, an empty LineString
couldn’t be instantiated.
closed
Returns whether or not this LineString
is closed.
LinearRing
class LinearRing(*args, **kwargs)
LinearRing
objects are constructed in the exact same way as LineString
objects, however the coordinates must be closed, in other words, the first coordinates must be the same as the last coordinates. For example:
>>> ls = LinearRing((0, 0), (0, 1), (1, 1), (0, 0))
Notice that (0, 0)
is the first and last coordinate – if they were not equal, an error would be raised.
Polygon
class Polygon(*args, **kwargs)
Polygon
objects may be instantiated by passing in parameters that represent the rings of the polygon. The parameters must either be LinearRing
instances, or a sequence that may be used to construct a LinearRing
:
>>> ext_coords = ((0, 0), (0, 1), (1, 1), (1, 0), (0, 0)) >>> int_coords = ((0.4, 0.4), (0.4, 0.6), (0.6, 0.6), (0.6, 0.4), (0.4, 0.4)) >>> poly = Polygon(ext_coords, int_coords) >>> poly = Polygon(LinearRing(ext_coords), LinearRing(int_coords))
In previous versions, an empty Polygon
couldn’t be instantiated.
classmethod from_bbox(bbox)
Returns a polygon object from the given boundingbox, a 4tuple comprising (xmin, ymin, xmax, ymax)
.
num_interior_rings
Returns the number of interior rings in this geometry.
Comparing Polygons
Note that it is possible to compare Polygon
objects directly with <
or >
, but as the comparison is made through Polygon’s LineString
, it does not mean much (but is consistent and quick). You can always force the comparison with the area
property:
>>> if poly_1.area > poly_2.area: >>> pass
MultiPoint
class MultiPoint(*args, **kwargs)
MultiPoint
objects may be instantiated by passing in Point
objects as arguments, or a single sequence of Point
objects:
>>> mp = MultiPoint(Point(0, 0), Point(1, 1)) >>> mp = MultiPoint( (Point(0, 0), Point(1, 1)) )
In previous versions, an empty MultiPoint
couldn’t be instantiated.
MultiLineString
class MultiLineString(*args, **kwargs)
MultiLineString
objects may be instantiated by passing in LineString
objects as arguments, or a single sequence of LineString
objects:
>>> ls1 = LineString((0, 0), (1, 1)) >>> ls2 = LineString((2, 2), (3, 3)) >>> mls = MultiLineString(ls1, ls2) >>> mls = MultiLineString([ls1, ls2])
In previous versions, an empty MultiLineString
couldn’t be instantiated.
merged
Returns a LineString
representing the line merge of all the components in this MultiLineString
.
closed
Returns True
if and only if all elements are closed. Requires GEOS 3.5.
MultiPolygon
class MultiPolygon(*args, **kwargs)
MultiPolygon
objects may be instantiated by passing Polygon
objects as arguments, or a single sequence of Polygon
objects:
>>> p1 = Polygon( ((0, 0), (0, 1), (1, 1), (0, 0)) ) >>> p2 = Polygon( ((1, 1), (1, 2), (2, 2), (1, 1)) ) >>> mp = MultiPolygon(p1, p2) >>> mp = MultiPolygon([p1, p2])
In previous versions, an empty MultiPolygon
couldn’t be instantiated.
cascaded_union
Deprecated since version 1.10: Use the GEOSGeometry.unary_union
property instead.
Returns a Polygon
that is the union of all of the component polygons in this collection. The algorithm employed is significantly more efficient (faster) than trying to union the geometries together individually. [2]
GeometryCollection
class GeometryCollection(*args, **kwargs)
GeometryCollection
objects may be instantiated by passing in other GEOSGeometry
as arguments, or a single sequence of GEOSGeometry
objects:
>>> poly = Polygon( ((0, 0), (0, 1), (1, 1), (0, 0)) ) >>> gc = GeometryCollection(Point(0, 0), MultiPoint(Point(0, 0), Point(1, 1)), poly) >>> gc = GeometryCollection((Point(0, 0), MultiPoint(Point(0, 0), Point(1, 1)), poly))
In previous versions, an empty GeometryCollection
couldn’t be instantiated.
In order to obtain a prepared geometry, just access the GEOSGeometry.prepared
property. Once you have a PreparedGeometry
instance its spatial predicate methods, listed below, may be used with other GEOSGeometry
objects. An operation with a prepared geometry can be orders of magnitude faster – the more complex the geometry that is prepared, the larger the speedup in the operation. For more information, please consult the GEOS wiki page on prepared geometries.
For example:
>>> from django.contrib.gis.geos import Point, Polygon >>> poly = Polygon.from_bbox((0, 0, 5, 5)) >>> prep_poly = poly.prepared >>> prep_poly.contains(Point(2.5, 2.5)) True
PreparedGeometry
class PreparedGeometry
All methods on PreparedGeometry
take an other
argument, which must be a GEOSGeometry
instance.
contains(other)
contains_properly(other)
covers(other)
crosses(other)
disjoint(other)
intersects(other)
overlaps(other)
touches(other)
within(other)
fromfile(file_h)
Parameters: 
file_h (a Python file object or a string path to the file) – input file that contains spatial data 

Return type:  a GEOSGeometry corresponding to the spatial data in the file 
Example:
>>> from django.contrib.gis.geos import fromfile >>> g = fromfile('/home/bob/geom.wkt')
fromstr(string, srid=None)
Parameters:  

Return type: 
a 
fromstr(string, srid)
is equivalent to GEOSGeometry(string, srid)
.
Example:
>>> from django.contrib.gis.geos import fromstr >>> pnt = fromstr('POINT(90.5 29.5)', srid=4326)
The reader I/O classes simply return a GEOSGeometry
instance from the WKB and/or WKT input given to their read(geom)
method.
class WKBReader
Example:
>>> from django.contrib.gis.geos import WKBReader >>> wkb_r = WKBReader() >>> wkb_r.read('0101000000000000000000F03F000000000000F03F') <Point object at 0x103a88910>
class WKTReader
Example:
>>> from django.contrib.gis.geos import WKTReader >>> wkt_r = WKTReader() >>> wkt_r.read('POINT(1 1)') <Point object at 0x103a88b50>
All writer objects have a write(geom)
method that returns either the WKB or WKT of the given geometry. In addition, WKBWriter
objects also have properties that may be used to change the byte order, and or include the SRID value (in other words, EWKB).
class WKBWriter(dim=2)
WKBWriter
provides the most control over its output. By default it returns OGCcompliant WKB when its write
method is called. However, it has properties that allow for the creation of EWKB, a superset of the WKB standard that includes additional information. See the WKBWriter.outdim
documentation for more details about the dim
argument.
The ability to pass the dim
argument to the constructor was added.
write(geom)
Returns the WKB of the given geometry as a Python buffer
object. Example:
>>> from django.contrib.gis.geos import Point, WKBWriter >>> pnt = Point(1, 1) >>> wkb_w = WKBWriter() >>> wkb_w.write(pnt) <readonly buffer for 0x103a898f0, size 1, offset 0 at 0x103a89930>
write_hex(geom)
Returns WKB of the geometry in hexadecimal. Example:
>>> from django.contrib.gis.geos import Point, WKBWriter >>> pnt = Point(1, 1) >>> wkb_w = WKBWriter() >>> wkb_w.write_hex(pnt) '0101000000000000000000F03F000000000000F03F'
byteorder
This property may be set to change the byteorder of the geometry representation.
Byteorder Value  Description 

0  Big Endian (e.g., compatible with RISC systems) 
1  Little Endian (e.g., compatible with x86 systems) 
Example:
>>> from django.contrib.gis.geos import Point, WKBWriter >>> wkb_w = WKBWriter() >>> pnt = Point(1, 1) >>> wkb_w.write_hex(pnt) '0101000000000000000000F03F000000000000F03F' >>> wkb_w.byteorder = 0 '00000000013FF00000000000003FF0000000000000'
outdim
This property may be set to change the output dimension of the geometry representation. In other words, if you have a 3D geometry then set to 3 so that the Z value is included in the WKB.
Outdim Value  Description 

2  The default, output 2D WKB. 
3  Output 3D WKB. 
Example:
>>> from django.contrib.gis.geos import Point, WKBWriter >>> wkb_w = WKBWriter() >>> wkb_w.outdim 2 >>> pnt = Point(1, 1, 1) >>> wkb_w.write_hex(pnt) # By default, no Z value included: '0101000000000000000000F03F000000000000F03F' >>> wkb_w.outdim = 3 # Tell writer to include Z values >>> wkb_w.write_hex(pnt) '0101000080000000000000F03F000000000000F03F000000000000F03F'
srid
Set this property with a boolean to indicate whether the SRID of the geometry should be included with the WKB representation. Example:
>>> from django.contrib.gis.geos import Point, WKBWriter >>> wkb_w = WKBWriter() >>> pnt = Point(1, 1, srid=4326) >>> wkb_w.write_hex(pnt) # By default, no SRID included: '0101000000000000000000F03F000000000000F03F' >>> wkb_w.srid = True # Tell writer to include SRID >>> wkb_w.write_hex(pnt) '0101000020E6100000000000000000F03F000000000000F03F'
class WKTWriter(dim=2, trim=False, precision=None)
This class allows outputting the WKT representation of a geometry. See the WKBWriter.outdim
, trim
, and precision
attributes for details about the constructor arguments.
The ability to pass the dim
, trim
, and precision
arguments to the constructor was added.
write(geom)
Returns the WKT of the given geometry. Example:
>>> from django.contrib.gis.geos import Point, WKTWriter >>> pnt = Point(1, 1) >>> wkt_w = WKTWriter() >>> wkt_w.write(pnt) 'POINT (1.0000000000000000 1.0000000000000000)'
outdim
See WKBWriter.outdim
.
trim
This property is used to enable or disable trimming of unnecessary decimals.
>>> from django.contrib.gis.geos import Point, WKTWriter >>> pnt = Point(1, 1) >>> wkt_w = WKTWriter() >>> wkt_w.trim False >>> wkt_w.write(pnt) 'POINT (1.0000000000000000 1.0000000000000000)' >>> wkt_w.trim = True >>> wkt_w.write(pnt) 'POINT (1 1)'
precision
This property controls the rounding precision of coordinates; if set to None
rounding is disabled.
>>> from django.contrib.gis.geos import Point, WKTWriter >>> pnt = Point(1.44, 1.66) >>> wkt_w = WKTWriter() >>> print(wkt_w.precision) None >>> wkt_w.write(pnt) 'POINT (1.4399999999999999 1.6599999999999999)' >>> wkt_w.precision = 0 >>> wkt_w.write(pnt) 'POINT (1 2)' >>> wkt_w.precision = 1 >>> wkt_w.write(pnt) 'POINT (1.4 1.7)'
[1]  See PostGIS EWKB, EWKT and Canonical Forms, PostGIS documentation at Ch. 4.1.2. 
[2]  For more information, read Paul Ramsey’s blog post about (Much) Faster Unions in PostGIS 1.4 and Martin Davis’ blog post on Fast polygon merging in JTS using Cascaded Union. 
GEOS_LIBRARY_PATH
A string specifying the location of the GEOS C library. Typically, this setting is only used if the GEOS C library is in a nonstandard location (e.g., /home/bob/lib/libgeos_c.so
).
Note
The setting must be the full path to the C shared library; in other words you want to use libgeos_c.so
, not libgeos.so
.
exception GEOSException
The base GEOS exception, indicates a GEOSrelated error.
© Django Software Foundation and individual contributors
Licensed under the BSD License.
https://docs.djangoproject.com/en/1.11/ref/contrib/gis/geos/