GeometriesΒΆ
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The geom module provides classes for representing two dimensional spatial
objects, or geometries. Geometry objects are created by specifying sets of
coordinates.
>>> from geoscrpt import geom
>>> point = geom.Point(10, 10)
>>> point
POINT (10 10)
>>> line = geom.LineString([10, 10], [20, 20], [30, 40])
>>> line
LINESTRING (10 10, 20 20, 30 40)
>> var GEOM = require("geoscript/geom");
>> var point = new GEOM.Point([10, 10]);
>> point
<Point [10, 10]>
>> var line = new GEOM.LineString([[10, 10], [20, 20], [30, 40]]);
>> line
<LineString [[10, 10], [20, 20], [30, 40]]>
scala> import org.geoscript.geometry._
import org.geoscript.geometry._
scala> val point = Point(10, 10)
point: org.geoscript.geometry.Point = POINT (10 10)
scala> val line = LineString((10, 10), (20, 20), (30, 40))
line: org.geoscript.geometry.LineString = LINESTRING (10 10, 20 20, 30 40)
groovy:000> import geoscript.geom.*
===> [import geoscript.geom.*]
groovy:000> p = new Point(10,10)
===> POINT (10 10)
groovy:000> line = new LineString([10,10],[20,20],[30,40])
===> LINESTRING (10 10, 20 20, 30 40)
Geometries can also be created from well known text representation.
>>> from geoscript import geom
>>> poly = geom.fromWKT('POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))')
>>> poly
POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
>> var parser = require("geoscript/io/wkt");
>> var poly = parser.read("POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))");
>> poly
<Polygon [[[10, 10], [10, 20], [20, 20], [20, 15], [10, 10]]]>
scala> import org.geoscript.geometry._
import org.geoscript.geometry._
scala> val poly = Geometry.fromWKT("POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))")
poly: org.geoscript.geometry.Geometry = POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
groovy:000> import geoscript.geom.*
===> [import geoscript.geom.*]
groovy:000> poly = Geometry.fromWKT("POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))")
===> POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
Geometry objects provide properties for statistics such as area and length.
>>> from geoscript import geom
>>> poly = geom.fromWKT('POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))')
>>> poly.area
75.0
>>> poly.length
36.180339887498945
>> var parser = require("geoscript/io/wkt");
>> var poly = parser.read("POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))");
>> poly.area
75
>> poly.length
36.180339887498945
scala> import org.geoscript.geometry._
import org.geoscript.geometry._
scala> val poly = Geometry.fromWKT("POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))")
poly: org.geoscript.geometry.Geometry = POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
scala> poly.area
res0: Double = 75
scala> poly.length
res0: Double = 36.180339887498945
groovy:000> import geoscript.geom.*
===> [import geoscript.geom.*]
groovy:000> poly = Geometry.fromWKT("POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))")
===> POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
groovy:000> poly.area
===> 75.0
groovy:000> poly.length
===> 36.180339887498945
There are also methods for calculating properties which are themselves geometries such as buffer and centroid.
>>> from geoscript import geom
>>> line = geom.LineString([10, 10], [20, 20], [30, 40])
>>> poly = line.buffer(10)
>>> poly.area
1041.9912814842407
>>> line.centroid
POINT (21.12574113277207 24.188611699158105)
>> var GEOM = require("geoscript/geom");
>> var line = new GEOM.LineString([[10, 10], [20, 20], [30, 40]]);
>> var poly = line.buffer(10);
>> poly.area
1041.9912814842407
>> line.centroid
<Point [21.12574113277207, 24.188611699158105]>
scala> import org.geoscript.GeoScript._
import org.geoscript.GeoScript._
scala> import org.geoscript.geometry._
import org.geoscript.geometry._
scala> val line = LineString((10, 10), (20, 20), (30, 40))
line: org.geoscript.geometry.LineString = LINESTRING (10 10, 20 20, 30 40)
scala> val poly = line.buffer(10)
poly: org.geoscript.geometry.Geometry = POLYGON ((11.781455848733053 25.923591472464004, 21.05572809000084 44.47213595499958, 22.100060210309515 46.13114600374718, 23.447982586398712 47.55453954995706, 25.04769531727891 48.68761637789669, 26.837722339831622 49.48683298050514, 28.74927391943886 49.921475911950004, 30.708890200906794 49.97484208812642, 32.64126422950409 49.6448806768120...
scala> poly.area
res0: Double = 1041.9912814842407
scala> line.centroid
res1: org.geoscript.geometry.Point = POINT (21.12574113277207 24.188611699158105)
groovy:000> import geoscript.geom.*
===> [import geoscript.geom.*]
groovy:000> line = new LineString([10,10],[20,20],[30,40])
===> LINESTRING (10 10, 20 20, 30 40)
groovy:000> poly = line.buffer(10)
===> POLYGON ((11.781455848733053 25.923591472464004, 21.05572809000084 44.47213595499958, 22.100060210309515 46.13114600374718, 23.447982586398712 47.55453954995706, 25.04769531727891 48.68761637789669, 26.837722339831622 49.48683298050514, 28.74927391943886 49.921475911950004, 30.708890200906794 49.97484208812642, 32.64126422950409 49.644880676812036, 34.47213595499958 48.94427190999916, 36.131146003747176 47.89993978969049, 37.55453954995706 46.55201741360129, 38.68761637789669 44.95230468272109, 39.48683298050514 43.16227766016838, 39.921475911950004 41.25072608056114, 39.97484208812642 39.2911097990932, 39.644880676812036 37.35873577049591, 38.94427190999916 35.52786404500042, 28.94427190999916 15.52786404500042, 28.112421851755606 14.15289715336235, 27.071067811865476 12.928932188134524, 17.071067811865476 2.9289321881345254, 15.555702330196024 1.6853038769745474, 13.826834323650898 0.7612046748871322, 11.950903220161283 0.1921471959676957, 10 0, 8.049096779838719 0.1921471959676957, 6.173165676349103 0.7612046748871322, 4.44429766980398 1.6853038769745474, 2.9289321881345254 2.9289321881345245, 1.6853038769745474 4.444297669803978, 0.7612046748871322 6.173165676349101, 0.1921471959676957 8.049096779838713, 0 9.999999999999998, 0.1921471959676957 11.950903220161283, 0.761204674887134 13.8268343236509, 1.685303876974551 15.555702330196027, 2.9289321881345254 17.071067811865476, 11.781455848733053 25.923591472464004))
groovy:000> poly.area
===> 1041.9912814842407
groovy:000> line.centroid
===> POINT (21.12574113277207 24.188611699158105)
The Geometry class also contains operations and predicates for
determining spatial relationships such as intersection and containment.
>>> from geoscript import geom
>>> poly = geom.Polygon([[10, 10], [10, 20], [20, 20], [20, 15], [10, 10]])
>>> line = geom.LineString([10, 10], [20, 20], [30, 40])
>>> poly.intersects(line)
True
>>> poly.intersection(line)
LINESTRING (10 10, 20 20)
>> var GEOM = require("geoscript/geom");
>> var line = new GEOM.LineString([[10, 10], [20, 20], [30, 40]]);
>> var poly = new GEOM.Polygon([[[10, 10], [10, 20], [20, 20], [20, 15], [10, 10]]]);
>> poly.intersects(line)
true
>> poly.intersection(line)
<LineString [[10, 10], [20, 20]]>
scala> import org.geoscript.geometry._
import org.geoscript.geometry._
scala> val line = LineString((10, 10), (20, 20), (30, 40))
line: org.geoscript.geometry.LineString = LINESTRING (10 10, 20 20, 30 40)
scala> val poly = Polygon(LineString((10, 10), (10, 20), (20, 20), (20, 15), (10, 10)), Nil)
poly: org.geoscript.geometry.Polygon = POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
scala> poly.intersects(line)
res0: Boolean = true
scala> poly.intersection(line)
res1: org.geoscript.geometry.Geometry = LINESTRING (10 10, 20 20)
groovy:000> import geoscript.geom.*
===> [import geoscript.geom.*]
groovy:000> line = new LineString([10,10], [20,20], [30,40])
===> LINESTRING (10 10, 20 20, 30 40)
groovy:000> poly = new Polygon([10,10],[10,20],[20,20],[20,15],[10,10])
===> POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))
groovy:000> poly.intersects(line)
===> true
groovy:000> poly.intersection(line)
===> LINESTRING (10 10, 20 20)
See also
The geoscript geometry module is based on the JTS library. Classes in the
geom module are extensions of their counterparts from JTS which
means any JTS geometry methods can be called on a geoscript geometry instance.
See the JTS javadocs
for more information.
See also
For full details on the available geometry types and their properties and
methods, see the JavaScript API reference for the
geom module.
