Coordinate operations#

count_coordinates(geometry)#

Counts the number of coordinate pairs in a geometry array.

Parameters
geometryGeometry or array_like

Examples

>>> from shapely import LineString, Point
>>> count_coordinates(Point(0, 0))
1
>>> count_coordinates(LineString([(2, 2), (4, 2)]))
2
>>> count_coordinates(None)
0
>>> count_coordinates([Point(0, 0), None])
1
get_coordinates(geometry, include_z=False, return_index=False)#

Gets coordinates from a geometry array as an array of floats.

The shape of the returned array is (N, 2), with N being the number of coordinate pairs. With the default of include_z=False, three-dimensional data is ignored. When specifying include_z=True, the shape of the returned array is (N, 3).

Parameters
geometryGeometry or array_like
include_zbool, default False

If, True include the third dimension in the output. If a geometry has no third dimension, the z-coordinates will be NaN.

return_indexbool, default False

If True, also return the index of each returned geometry as a separate ndarray of integers. For multidimensional arrays, this indexes into the flattened array (in C contiguous order).

Examples

>>> from shapely import LineString, Point
>>> get_coordinates(Point(0, 0)).tolist()
[[0.0, 0.0]]
>>> get_coordinates(LineString([(2, 2), (4, 4)])).tolist()
[[2.0, 2.0], [4.0, 4.0]]
>>> get_coordinates(None)
array([], shape=(0, 2), dtype=float64)

By default the third dimension is ignored:

>>> get_coordinates(Point(0, 0, 0)).tolist()
[[0.0, 0.0]]
>>> get_coordinates(Point(0, 0, 0), include_z=True).tolist()
[[0.0, 0.0, 0.0]]

When return_index=True, indexes are returned also:

>>> geometries = [LineString([(2, 2), (4, 4)]), Point(0, 0)]
>>> coordinates, index = get_coordinates(geometries, return_index=True)
>>> coordinates.tolist(), index.tolist()
([[2.0, 2.0], [4.0, 4.0], [0.0, 0.0]], [0, 0, 1])
set_coordinates(geometry, coordinates)#

Adapts the coordinates of a geometry array in-place.

If the coordinates array has shape (N, 2), all returned geometries will be two-dimensional, and the third dimension will be discarded, if present. If the coordinates array has shape (N, 3), the returned geometries preserve the dimensionality of the input geometries.

Warning

The geometry array is modified in-place! If you do not want to modify the original array, you can do set_coordinates(arr.copy(), newcoords).

Parameters
geometryGeometry or array_like
coordinates: array_like

See also

transform

Returns a copy of a geometry array with a function applied to its coordinates.

Examples

>>> from shapely import LineString, Point
>>> set_coordinates(Point(0, 0), [[1, 1]])
<POINT (1 1)>
>>> set_coordinates([Point(0, 0), LineString([(0, 0), (0, 0)])], [[1, 2], [3, 4], [5, 6]]).tolist()
[<POINT (1 2)>, <LINESTRING (3 4, 5 6)>]
>>> set_coordinates([None, Point(0, 0)], [[1, 2]]).tolist()
[None, <POINT (1 2)>]

Third dimension of input geometry is discarded if coordinates array does not include one:

>>> set_coordinates(Point(0, 0, 0), [[1, 1]])
<POINT (1 1)>
>>> set_coordinates(Point(0, 0, 0), [[1, 1, 1]])
<POINT Z (1 1 1)>
transform(geometry, transformation, include_z=False)#

Returns a copy of a geometry array with a function applied to its coordinates.

With the default of include_z=False, all returned geometries will be two-dimensional; the third dimension will be discarded, if present. When specifying include_z=True, the returned geometries preserve the dimensionality of the respective input geometries.

Parameters
geometryGeometry or array_like
transformationfunction

A function that transforms a (N, 2) or (N, 3) ndarray of float64 to another (N, 2) or (N, 3) ndarray of float64.

include_zbool, default False

If True, include the third dimension in the coordinates array that is passed to the transformation function. If a geometry has no third dimension, the z-coordinates passed to the function will be NaN.

Examples

>>> from shapely import LineString, Point
>>> transform(Point(0, 0), lambda x: x + 1)
<POINT (1 1)>
>>> transform(LineString([(2, 2), (4, 4)]), lambda x: x * [2, 3])
<LINESTRING (4 6, 8 12)>
>>> transform(None, lambda x: x) is None
True
>>> transform([Point(0, 0), None], lambda x: x).tolist()
[<POINT (0 0)>, None]

By default, the third dimension is ignored:

>>> transform(Point(0, 0, 0), lambda x: x + 1)
<POINT (1 1)>
>>> transform(Point(0, 0, 0), lambda x: x + 1, include_z=True)
<POINT Z (1 1 1)>