geos::algorithm::Centroid Class Reference

Computes the centroid of a Geometry of any dimension. More...

#include <Centroid.h>

Public Member Functions
	Centroid (const geom::Geometry &geom)
	Creates a new instance for computing the centroid of a geometry.
bool	getCentroid (geom::Coordinate &cent) const
	Gets the computed centroid. More...

Static Public Member Functions
static bool	getCentroid (const geom::Geometry &geom, geom::Coordinate &cent)
	Computes the centroid point of a geometry. More...

Detailed Description

Computes the centroid of a Geometry of any dimension.

If the geometry is nomimally of higher dimension, but contains only components having a lower effective dimension (i.e. zero length or area), the centroid will be computed appropriately.

Algorithm

• Dimension = 2 - Based on the usual algorithm for calculating the centroid as a weighted sum of the centroids of a decomposition of the area into (possibly overlapping) triangles. The algorithm has been extended to handle holes and multi-polygons. See http://www.faqs.org/faqs/graphics/algorithms-faq/ for further details of the basic approach.
• Dimension = 1 - Computes the average of the midpoints of all line segments weighted by the segment length.
• Dimension = 0 - Compute the average coordinate over all points.

If the input geometries are empty, a null Coordinate is returned.

Member Function Documentation

getCentroid() [1/2]

static bool geos::algorithm::Centroid::getCentroid ( const geom::Geometry &  geom, geom::Coordinate &  cent  )

static

Computes the centroid point of a geometry.

Parameters

geom	the geometry to use
cent	will be set to the centroid point, if any

Returns

true if a centroid could be computed, false otherwise (empty geom)

getCentroid() [2/2]

bool geos::algorithm::Centroid::getCentroid

(

geom::Coordinate &

cent

)

const

Gets the computed centroid.

Parameters

cent	will be set to the centroid point, if any

Returns

true if a centroid could be computed, false otherwise (empty geom)

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The documentation for this class was generated from the following file:

• Centroid.h