geos::algorithm::Centroid Class Reference

#include <Centroid.h>

List of all members.

Public Member Functions
	Centroid (const geom::Geometry &geom)
bool	getCentroid (geom::Coordinate &cent) const
Static Public Member Functions
static bool	getCentroid (const geom::Geometry &geom, geom::Coordinate &cent)

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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.

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Constructor & Destructor Documentation

geos::algorithm::Centroid::Centroid

(

const geom::Geometry &

geom

)

[inline]

Creates a new instance for computing the centroid of a geometry

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Member Function Documentation

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)

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)

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

• Centroid.h