Measurement¶
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pygeos.measurement.
area
(geometry, **kwargs)¶ Computes the area of a (multi)polygon.
- Parameters
geometry : Geometry or array_like
Examples
>>> area(Geometry("POLYGON((0 0, 0 10, 10 10, 10 0, 0 0))")) 100.0 >>> area(Geometry("MULTIPOLYGON (((0 0, 0 10, 10 10, 0 0)), ((0 0, 0 10, 10 10, 0 0)))")) 100.0 >>> area(Geometry("POLYGON EMPTY")) 0.0 >>> area(None) nan
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pygeos.measurement.
bounds
(geometry, **kwargs)¶ Computes the bounds (extent) of a geometry.
For each geometry these 4 numbers are returned: min x, min y, max x, max y.
- Parameters
geometry : Geometry or array_like
Examples
>>> bounds(Geometry("POINT (2 3)")).tolist() [2.0, 3.0, 2.0, 3.0] >>> bounds(Geometry("LINESTRING (0 0, 0 2, 3 2)")).tolist() [0.0, 0.0, 3.0, 2.0] >>> bounds(Geometry("POLYGON EMPTY")).tolist() [nan, nan, nan, nan] >>> bounds(None).tolist() [nan, nan, nan, nan]
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pygeos.measurement.
distance
(a, b, **kwargs)¶ Computes the Cartesian distance between two geometries.
- Parameters
a, b : Geometry or array_like
Examples
>>> point = Geometry("POINT (0 0)") >>> distance(Geometry("POINT (10 0)"), point) 10.0 >>> distance(Geometry("LINESTRING (1 1, 1 -1)"), point) 1.0 >>> distance(Geometry("POLYGON ((3 0, 5 0, 5 5, 3 5, 3 0))"), point) 3.0 >>> distance(Geometry("POINT EMPTY"), point) nan >>> distance(None, point) nan
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pygeos.measurement.
frechet_distance
(a, b, densify=None, **kwargs)¶ Compute the discrete Fréchet distance between two geometries.
The Fréchet distance is a measure of similarity: it is the greatest distance between any point in A and the closest point in B. The discrete distance is an approximation of this metric: only vertices are considered. The parameter ‘densify’ makes this approximation less coarse by splitting the line segments between vertices before computing the distance.
Fréchet distance sweep continuously along their respective curves and the direction of curves is significant. This makes it a better measure of similarity than Hausdorff distance for curve or surface matching.
- Parameters
a, b : Geometry or array_like
densify : float, array_like or None
The value of densify is required to be between 0 and 1.
Examples
>>> line_1 = Geometry("LINESTRING (0 0, 100 0)") >>> line_2 = Geometry("LINESTRING (0 0, 50 50, 100 0)") >>> frechet_distance(line_1, line_2) 70.71... >>> frechet_distance(line_1, line_2, densify=0.5) 50.0 >>> frechet_distance(line_1, Geometry("LINESTRING EMPTY")) nan >>> frechet_distance(line_1, None) nan
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pygeos.measurement.
hausdorff_distance
(a, b, densify=None, **kwargs)¶ Compute the discrete Hausdorff distance between two geometries.
The Hausdorff distance is a measure of similarity: it is the greatest distance between any point in A and the closest point in B. The discrete distance is an approximation of this metric: only vertices are considered. The parameter ‘densify’ makes this approximation less coarse by splitting the line segments between vertices before computing the distance.
- Parameters
a, b : Geometry or array_like
densify : float, array_like or None
The value of densify is required to be between 0 and 1.
Examples
>>> line_1 = Geometry("LINESTRING (130 0, 0 0, 0 150)") >>> line_2 = Geometry("LINESTRING (10 10, 10 150, 130 10)") >>> hausdorff_distance(line_1, line_2) 14.14... >>> hausdorff_distance(line_1, line_2, densify=0.5) 70.0 >>> hausdorff_distance(line_1, Geometry("LINESTRING EMPTY")) nan >>> hausdorff_distance(line_1, None) nan
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pygeos.measurement.
length
(geometry, **kwargs)¶ Computes the length of a (multi)linestring or polygon perimeter.
- Parameters
geometry : Geometry or array_like
Examples
>>> length(Geometry("LINESTRING (0 0, 0 2, 3 2)")) 5.0 >>> length(Geometry("MULTILINESTRING ((0 0, 1 0), (0 0, 1 0))")) 2.0 >>> length(Geometry("POLYGON((0 0, 0 10, 10 10, 10 0, 0 0))")) 40.0 >>> length(Geometry("LINESTRING EMPTY")) 0.0 >>> length(None) nan
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pygeos.measurement.
total_bounds
(geometry, **kwargs)¶ Computes the total bounds (extent) of the geometry.
- Parameters
geometry : Geometry or array_like
- Returns
numpy ndarray of [xmin, ymin, xmax, ymax]
>>> total_bounds(Geometry("POINT (2 3)")).tolist()
[2.0, 3.0, 2.0, 3.0]
>>> total_bounds([Geometry("POINT (2 3)"), Geometry("POINT (4 5)")]).tolist()
[2.0, 3.0, 4.0, 5.0]
>>> total_bounds([Geometry("LINESTRING (0 1, 0 2, 3 2)"),Geometry("LINESTRING (4 4, 4 6, 6 7)")]).tolist()
[0.0, 1.0, 6.0, 7.0]
>>> total_bounds(Geometry("POLYGON EMPTY")).tolist()
[nan, nan, nan, nan]
>>> total_bounds([Geometry("POLYGON EMPTY"), Geometry("POINT (2 3)")]).tolist()
[2.0, 3.0, 2.0, 3.0]
>>> total_bounds(None).tolist()
[nan, nan, nan, nan]