Geometry handling functions: advanced. More...

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Macros
#define	GAIA2GEOS_ALL 0
#define	GAIA2GEOS_ONLY_POINTS 1
#define	GAIA2GEOS_ONLY_LINESTRINGS 2
#define	GAIA2GEOS_ONLY_POLYGONS 3

Functions
GAIAGEO_DECLARE double	gaiaRadsToDegs (double rads)
	Converts and angle from Radians into Degrees.
GAIAGEO_DECLARE double	gaiaDegsToRads (double degs)
	Converts and angle from Degrees into Radians.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaTransform (gaiaGeomCollPtr org, char proj_from, char proj_to)
	Tansforms a Geometry object into a different Reference System [aka Reprojection].
GAIAGEO_DECLARE void	gaiaResetGeosMsg (void)
	Resets the GEOS error and warning messages to an empty state.
GAIAGEO_DECLARE const char *	gaiaGetGeosErrorMsg (void)
	Return the latest GEOS error message (if any)
GAIAGEO_DECLARE const char *	gaiaGetGeosWarningMsg (void)
	Return the latest GEOS warning message (if any)
GAIAGEO_DECLARE void	gaiaSetGeosErrorMsg (const char *msg)
	Set the current GEOS error message.
GAIAGEO_DECLARE void	gaiaSetGeosWarningMsg (const char *msg)
	Set the current GEOS warning message.
GAIAGEO_DECLARE void *	gaiaToGeos (const gaiaGeomCollPtr gaia)
	Converts a Geometry object into a GEOS Geometry.
GAIAGEO_DECLARE void *	gaiaToGeosSelective (const gaiaGeomCollPtr gaia, int mode)
	Converts a Geometry object into a GEOS Geometry.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaFromGeos_XY (const void *geos)
	Converts a GEOS Geometry into a Geometry object [XY dims].
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaFromGeos_XYZ (const void *geos)
	Converts a GEOS Geometry into a Geometry object [XYZ dims].
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaFromGeos_XYM (const void *geos)
	Converts a GEOS Geometry into a Geometry object [XYM dims].
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaFromGeos_XYZM (const void *geos)
	Converts a GEOS Geometry into a Geometry object [XYZM dims].
GAIAGEO_DECLARE int	gaiaIsSimple (gaiaGeomCollPtr geom)
	Checks if a Geometry object represents an OGC Simple Geometry.
GAIAGEO_DECLARE int	gaiaIsClosed (gaiaLinestringPtr line)
	Checks if a Linestring object represents an OGC Closed Geometry.
GAIAGEO_DECLARE int	gaiaIsClosedGeom (gaiaGeomCollPtr geom)
	Checks if a Geometry object represents an OGC Closed Linestring.
GAIAGEO_DECLARE int	gaiaIsRing (gaiaLinestringPtr line)
	Checks if a Linestring object represents an OGC Ring Geometry.
GAIAGEO_DECLARE int	gaiaIsValid (gaiaGeomCollPtr geom)
	Checks if a Geometry object represents an OGC Valid Geometry.
GAIAGEO_DECLARE int	gaiaGeomCollLength (gaiaGeomCollPtr geom, double *length)
	Measures the total Length for a Geometry object.
GAIAGEO_DECLARE int	gaiaGeomCollLengthOrPerimeter (gaiaGeomCollPtr geom, int perimeter, double *length)
	Measures the total Length or Perimeter for a Geometry object.
GAIAGEO_DECLARE int	gaiaGeomCollArea (gaiaGeomCollPtr geom, double *area)
	Measures the total Area for a Geometry object.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaPolygonize (gaiaGeomCollPtr geom, int force_multi)
	Attempts to rearrange a generic Geometry object into a Polygon or MultiPolygon.
GAIAGEO_DECLARE int	gaiaGeomCollEquals (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Equals.
GAIAGEO_DECLARE int	gaiaGeomCollDisjoint (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Disjoint.
GAIAGEO_DECLARE int	gaiaGeomCollIntersects (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Intesects.
GAIAGEO_DECLARE int	gaiaGeomCollOverlaps (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Overlaps.
GAIAGEO_DECLARE int	gaiaGeomCollCrosses (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Crosses.
GAIAGEO_DECLARE int	gaiaGeomCollContains (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Contains.
GAIAGEO_DECLARE int	gaiaGeomCollWithin (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Within.
GAIAGEO_DECLARE int	gaiaGeomCollTouches (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial relationship evalution: Touches.
GAIAGEO_DECLARE int	gaiaGeomCollRelate (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, const char *pattern)
	Spatial relationship evalution: Relate.
GAIAGEO_DECLARE int	gaiaGeomCollDistance (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, double *dist)
	Calculates the maximum distance intercurring between two Geometry objects.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeometryIntersection (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: Intersection.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeometryUnion (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: Union.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaUnionCascaded (gaiaGeomCollPtr geom)
	Spatial operator: Union Cascaded.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeometryDifference (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: Difference.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeometrySymDifference (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: SymDifference.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaBoundary (gaiaGeomCollPtr geom)
	Spatial operator: Boundary.
GAIAGEO_DECLARE int	gaiaGeomCollCentroid (gaiaGeomCollPtr geom, double x, double y)
	Spatial operator: Centroid.
GAIAGEO_DECLARE int	gaiaGetPointOnSurface (gaiaGeomCollPtr geom, double x, double y)
	Spatial operator: PointOnSurface.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeomCollSimplify (gaiaGeomCollPtr geom, double tolerance)
	Spatial operator: Simplify.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeomCollSimplifyPreserveTopology (gaiaGeomCollPtr geom, double tolerance)
	Spatial operator: Simplify [preserving topology].
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaConvexHull (gaiaGeomCollPtr geom)
	Spatial operator: ConvexHull.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaGeomCollBuffer (gaiaGeomCollPtr geom, double radius, int points)
	Spatial operator: Buffer.
GAIAGEO_DECLARE int	gaiaHausdorffDistance (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, double *dist)
	Calculates the Hausdorff distance intercurring between two Geometry objects.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaOffsetCurve (gaiaGeomCollPtr geom, double radius, int points, int left_right)
	Spatial operator: Offset Curve.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSingleSidedBuffer (gaiaGeomCollPtr geom, double radius, int points, int left_right)
	Spatial operator: Single Sided Buffer.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSharedPaths (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: Shared Paths.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaLineInterpolatePoint (gaiaGeomCollPtr ln_geom, double fraction)
	Spatial operator: Line Interpolate Point.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaLineInterpolateEquidistantPoints (gaiaGeomCollPtr ln_geom, double distance)
	Spatial operator: Line Interpolate Equidistant Points.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaLineSubstring (gaiaGeomCollPtr ln_geom, double start_fraction, double end_fraction)
	Spatial operator: Line Substring.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaShortestLine (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: Shortest Line.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSnap (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, double tolerance)
	Spatial operator: Shortest Line.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaLineMerge (gaiaGeomCollPtr geom)
	Spatial operator: Line Merge.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaLinesCutAtNodes (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Spatial operator: Line Cut At Nodes.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaUnaryUnion (gaiaGeomCollPtr geom)
	Spatial operator: Unary Union.
GAIAGEO_DECLARE double	gaiaLineLocatePoint (gaiaGeomCollPtr ln_geom, gaiaGeomCollPtr pt_geom)
	Determines the location of the closest Point on Linestring to the given Point.
GAIAGEO_DECLARE int	gaiaGeomCollCovers (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Topology check: test if a Geometry covers another one.
GAIAGEO_DECLARE int	gaiaGeomCollCoveredBy (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2)
	Topology check: test if a Geometry is covered by another one.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSquareGrid (gaiaGeomCollPtr geom, double origin_x, double origin_y, double size, int only_edges)
	Utility function: SquareGrid.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaTriangularGrid (gaiaGeomCollPtr geom, double origin_x, double origin_y, double size, int only_edges)
	Utility function: TriangularGrid.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaHexagonalGrid (gaiaGeomCollPtr geom, double origin_x, double origin_y, double size, int only_edges)
	Utility function: HexagonalGrid.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaDelaunayTriangulation (gaiaGeomCollPtr geom, double tolerance, int only_edges)
	Delaunay Triangulation.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaVoronojDiagram (gaiaGeomCollPtr geom, double extra_frame_size, double tolerance, int only_edges)
	Voronoj Diagram.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaConcaveHull (gaiaGeomCollPtr geom, double factor, double tolerance, int allow_holes)
	Concave Hull.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaMakeValid (gaiaGeomCollPtr geom)
	Utility function: MakeValid.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaMakeValidDiscarded (gaiaGeomCollPtr geom)
	Utility function: MakeValidDiscarded.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSegmentize (gaiaGeomCollPtr geom, double dist)
	Utility function: Segmentize.
GAIAGEO_DECLARE int	gaiaAzimuth (double xa, double ya, double xb, double yb, double *azimuth)
	Utility function: Azimuth.
GAIAGEO_DECLARE char *	gaiaGeoHash (gaiaGeomCollPtr geom, int precision)
	Utility function: GeoHash.
GAIAGEO_DECLARE char *	gaiaAsX3D (gaiaGeomCollPtr geom, const char srs, int precision, int options, const char defid)
	Utility function: AsX3D.
GAIAGEO_DECLARE int	gaia3DDistance (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, double *dist)
	Calculates the minimum 3D distance intercurring between two Geometry objects.
GAIAGEO_DECLARE int	gaiaMaxDistance (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, double *dist)
	Calculates the maximum 2D distance intercurring between two Geometry objects.
GAIAGEO_DECLARE int	gaia3DMaxDistance (gaiaGeomCollPtr geom1, gaiaGeomCollPtr geom2, double *dist)
	Calculates the maximum 3D distance intercurring between two Geometry objects.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSplit (gaiaGeomCollPtr input, gaiaGeomCollPtr blade)
	Utility function: Split.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSplitLeft (gaiaGeomCollPtr input, gaiaGeomCollPtr blade)
	Utility function: SplitLeft.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSplitRight (gaiaGeomCollPtr input, gaiaGeomCollPtr blade)
	Utility function: SplitRight.
GAIAGEO_DECLARE gaiaGeomCollPtr	gaiaSnapToGrid (gaiaGeomCollPtr geom, double origin_x, double origin_y, double origin_z, double origin_m, double size_x, double size_y, double size_z, double size_m)
	Utility function: SnapToGrid.

Detailed Description

Geometry handling functions: advanced.

Function Documentation

GAIAGEO_DECLARE int gaia3DDistance	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		double *	dist
	)

Calculates the minimum 3D distance intercurring between two Geometry objects.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object
dist	on completion this variable will contain the calculated distance

Returns:: 0 on failure: any other value on success.

See also:: gaiaGeomCollDistance, gaiaMaxDistance, gaia3DMaxDisance

Note:: this function computes the 3D cartesian distance (if Z is supported)

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE int gaia3DMaxDistance	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		double *	dist
	)

Calculates the maximum 3D distance intercurring between two Geometry objects.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object
dist	on completion this variable will contain the calculated distance

Returns:: 0 on failure: any other value on success.

See also:: gaiaGeomCollDistance, gaia3DDistance, gaiaMaxDistance

Note:: this function computes the 3D maximum cartesian distance (if Z is supported)

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE char* gaiaAsX3D	(	gaiaGeomCollPtr	geom,
		const char *	srs,
		int	precision,
		int	options,
		const char *	defid
	)

Utility function: AsX3D.

Parameters:

geom	the input geometry.
srs	the WKT SRS definition.
precision	the expected precision (coord decimal digits).
options
refid	the X3D namespace

Returns:: NULL on failure: a null-terminated text string on success

Note:: you are responsible to free (before or after) any text string returned by gaiaAsX3D()

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE int gaiaAzimuth	(	double	xa,
		double	ya,
		double	xb,
		double	yb,
		double *	azimuth
	)

Utility function: Azimuth.

Parameters:

xa	the X ccordinate of PointA.
ya	the Y coordinate of PointA.
xb	the X ccordinate of PointB.
yb	the Y coordinate of PointB.
azimuth	on completion this variable will contain the angle in radians from the horizontal of the vector defined by pointA and pointB. Angle is computed clockwise from down-to-up: on the clock: 12=0; 3=PI/2; 6=PI; 9=3PI/2.

Returns:: 0 on failure: any other value on success

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaBoundary ( gaiaGeomCollPtr geom )

Spatial operator: Boundary.

Parameters:

geom	the Geometry object to be evaluated

Returns:: the pointer to newly created Geometry object representing the geometry Boundary of the input Geometry: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaBoundary()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaConcaveHull	(	gaiaGeomCollPtr	geom,
		double	factor,
		double	tolerance,
		int	allow_holes
	)

Concave Hull.

Parameters:

geom	pointer to input Geometry object.
factor	multiplier used for filtering Delaunay triangles: please read the note.
tolerance	optional snapping tolerance.
allow_hows	if FALSE any interior hole will be suppressed.

Returns:: the pointer to newly created Geometry object (always of the Polygon type): NULL on failure.
NULL will be returned if any argument is invalid.

See also:: gaiaFreeGeomColl, gaiaDelaunayTriangulation

Note:: This function will first create the Delauany Triangulation corresponding to input Geometry, determining at the same time the standard deviation for all edge's lengths.
Then in a second pass all Delaunay's triangles will be filtered, and all triangles presenting at least one edge longer than standard deviation * factor will be discarded.
All filtered triangles will then be merged altogether so to create the Concave Hull.; you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaConcaveHull()

Remarks:: GEOS-TRUNK support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaConvexHull ( gaiaGeomCollPtr geom )

Spatial operator: ConvexHull.

Parameters:

geom	the input Geometry object

Returns:: the pointer to newly created Geometry object representing the ConvexHull of input Geometry: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaConvexHull()

Remarks:: GEOS support required.

GAIAGEO_DECLARE double gaiaDegsToRads ( double degs )

Converts and angle from Degrees into Radians.

Parameters:

degs	the angle measured in Degrees.

Returns:: the angle measured in Radians.

See also:: gaiaRadsToDegs

Remarks:: PROJ.4 support required

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaDelaunayTriangulation	(	gaiaGeomCollPtr	geom,
		double	tolerance,
		int	only_edges
	)

Delaunay Triangulation.

Parameters:

geom	pointer to input Geometry object.
tolerance	optional snapping tolerance.
only_edges	if non-zero will return a MULTILINESTRING, otherwise it will return a MULTIPOLYGON containing triangular POLYGONs.

Returns:: the pointer to newly created Geometry object: NULL on failure.
NULL will be returned if any argument is invalid.

See also:: gaiaFreeGeomColl, gaiaVoronojDiagram, gaiaConcaveHull

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaDelaunayTriangulation()

Remarks:: GEOS-TRUNK support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaFromGeos_XY ( const void * geos )

Converts a GEOS Geometry into a Geometry object [XY dims].

Parameters:

geos	handle to GEOS Geometry

Returns:: the pointer to the newly created Geometry object

See also:: gaiaToGeos, gaiaFromGeos_XYZ, gaiaFromGeos_XYM, gaiaFromGeos_XYZM

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaFromGeos_XY()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaFromGeos_XYM ( const void * geos )

Converts a GEOS Geometry into a Geometry object [XYM dims].

Parameters:

geos	handle to GEOS Geometry

Returns:: the pointer to the newly created Geometry object

See also:: gaiaToGeos, gaiaFromGeos_XY, gaiaFromGeos_XYZ, gaiaFromGeos_XYZM

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaFromGeos_XYM()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaFromGeos_XYZ ( const void * geos )

Converts a GEOS Geometry into a Geometry object [XYZ dims].

Parameters:

geos	handle to GEOS Geometry

Returns:: the pointer to the newly created Geometry object

See also:: gaiaToGeos, gaiaFromGeos_XY, gaiaFromGeos_XYM, gaiaFromGeos_XYZM

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaFromGeos_XYZ()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaFromGeos_XYZM ( const void * geos )

Converts a GEOS Geometry into a Geometry object [XYZM dims].

Parameters:

geos	handle to GEOS Geometry

Returns:: the pointer to the newly created Geometry object

See also:: gaiaToGeos, gaiaFromGeos_XY, gaiaFromGeos_XYZ, gaiaFromGeos_XYM

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaFromGeos_XYZM()

Remarks:: GEOS support required.

GAIAGEO_DECLARE char* gaiaGeoHash	(	gaiaGeomCollPtr	geom,
		int	precision
	)

Utility function: GeoHash.

Parameters:

geom	the input geometry.
precision	the expected precision: if <= 0 will be automatically determined.

Returns:: NULL on failure: a null-terminated text string on success

Note:: you are responsible to free (before or after) any text string returned by gaiaGeoHash()

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE int gaiaGeomCollArea	(	gaiaGeomCollPtr	geom,
		double *	area
	)

Measures the total Area for a Geometry object.

Parameters:

geom	pointer to Geometry object
area	on completion this variable will contain the measured area

Returns:: 0 on failure: any other value on success

See also:: gaiaGeomCollLength, gaiaMeasureArea

Remarks:: GEOS support required.

Examples:: demo1.c.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeomCollBuffer	(	gaiaGeomCollPtr	geom,
		double	radius,
		int	points
	)

Spatial operator: Buffer.

Parameters:

geom	the input Geometry object
radius	the buffer's radius
points	number of points (aka vertices) to be used in order to approximate a circular arc.

Returns:: the pointer to newly created Geometry object representing the Buffer of input Geometry: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeomCollBuffer()

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollCentroid	(	gaiaGeomCollPtr	geom,
		double *	x,
		double *	y
	)

Spatial operator: Centroid.

Parameters:

geom	pointer to Geometry object.
x	on completion this variable will contain the centroid X coordinate
y	on completion this variable will contain the centroid Y coordinate

Returns:: 0 on failure: any other value on success

See also:: gaiaRingCentroid

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollContains	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Contains.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollWithin, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollCoveredBy	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Topology check: test if a Geometry is covered by another one.

Parameters:

geom1	pointer to first input Geometry object.
geom2	pointer to second input Geometry object.

Returns:: 0 if false; any other value if geom2 is spatially covered by geom1.

See also:: gaiaGeomCollCovers

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE int gaiaGeomCollCovers	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Topology check: test if a Geometry covers another one.

Parameters:

geom1	pointer to first input Geometry object.
geom2	pointer to second input Geometry object.

Returns:: 0 if false; any other value if geom1 spatially covers geom2.

See also:: gaiaGeomCollCoveredBy

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE int gaiaGeomCollCrosses	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Crosses.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollDisjoint	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Disjoint.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollDistance	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		double *	dist
	)

Calculates the maximum distance intercurring between two Geometry objects.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object
dist	on completion this variable will contain the calculated distance

Returns:: 0 on failure: any other value on success.

See also:: gaia3DDistance, gaiaMaxDistance, gaia3DMaxDistance

Note:: this function always computes the 2D cartesian distance.

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollEquals	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Equals.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollIntersects	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Intesects.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollLength	(	gaiaGeomCollPtr	geom,
		double *	length
	)

Measures the total Length for a Geometry object.

Parameters:

geom	pointer to Geometry object
length	on completion this variable will contain the measured length

Returns:: 0 on failure: any other value on success

See also:: gaiaGeomCollArea, gaiaMeasureLength, gaiaGeomCollLengthOrPerimeter

Remarks:: GEOS support required.

Examples:: demo1.c.

GAIAGEO_DECLARE int gaiaGeomCollLengthOrPerimeter	(	gaiaGeomCollPtr	geom,
		int	perimeter,
		double *	length
	)

Measures the total Length or Perimeter for a Geometry object.

Parameters:

geom	pointer to Geometry object
perimeter	if TRUE only Polygons will be considered, ignoring any Linesting the opposite if FALSE (considering only Linestrings and ignoring any Polygon)
length	on completion this variable will contain the measured length or perimeter

Returns:: 0 on failure: any other value on success

See also:: gaiaGeomCollArea, gaiaMeasureLength, gaiaGeomCollLength

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollOverlaps	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Overlaps.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollRelate	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		const char *	pattern
	)

Spatial relationship evalution: Relate.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated
pattern	intersection matrix pattern [DE-9IM]

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollTouches

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeomCollSimplify	(	gaiaGeomCollPtr	geom,
		double	tolerance
	)

Spatial operator: Simplify.

Parameters:

geom	the input Geometry object
tolerance	approximation threshold

Returns:: the pointer to newly created Geometry object representing the simplified Geometry [applying the Douglas-Peucker algorithm]: NULL on failure.

See also:: gaiaFreeGeomColl, gaiaGeomCollSimplifyPreserveTopology

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeomCollSimplify()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeomCollSimplifyPreserveTopology	(	gaiaGeomCollPtr	geom,
		double	tolerance
	)

Spatial operator: Simplify [preserving topology].

Parameters:

geom	the input Geometry object
tolerance	approximation threshold

Returns:: the pointer to newly created Geometry object representing the simplified Geometry [applying the Douglas-Peucker algorithm]: NULL on failure.

See also:: gaiaFreeGeomColl, gaiaGeomCollSimplify

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeomCollSimplify()

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollTouches	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Touches.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollWithin, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGeomCollWithin	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial relationship evalution: Within.

Parameters:

geom1	the first Geometry object to be evaluated
geom2	the second Geometry object to be evaluated

Returns:: 0 if false: any other value if true

See also:: gaiaGeomCollEquals, gaiaGeomCollDisjoint, gaiaGeomCollIntersects, gaiaGeomCollOverlaps, gaiaGeomCollCrosses, gaiaGeomCollContains, gaiaGeomCollTouches, gaiaGeomCollRelate

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeometryDifference	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: Difference.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object

Returns:: the pointer to newly created Geometry object representing the geometry Difference of both input Geometries: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeometryDifference()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeometryIntersection	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: Intersection.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object

Returns:: the pointer to newly created Geometry object representing the geometry Intersection of both input Geometries: NULL on failure.

See also:: gaiaFreeGeomColl, gaiaGeometryUnion, gaiaGeometryDifference, gaiaGeometrySymDifference, gaiaBoundary

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeometryIntersection()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeometrySymDifference	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: SymDifference.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object

Returns:: the pointer to newly created Geometry object representing the geometry SymDifference of both input Geometries: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeometrySymDifference()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaGeometryUnion	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: Union.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object

Returns:: the pointer to newly created Geometry object representing the geometry Union of both input Geometries: NULL on failure.

See also:: gaiaFreeGeomColl, gaiaUnaryUnion, gaiaUnionCascaded

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeometryUnion()

Remarks:: GEOS support required.

GAIAGEO_DECLARE const char* gaiaGetGeosErrorMsg ( void )

Return the latest GEOS error message (if any)

Returns:: the latest GEOS error message: an empty string if no error was previoysly found.

See also:: gaiaResetGeosMsg, gaiaGetGeosWarningMsg, gaiaSetGeosErrorMsg, gaiaSetGeosWarningMsg

Remarks:: GEOS support required.

GAIAGEO_DECLARE const char* gaiaGetGeosWarningMsg ( void )

Return the latest GEOS warning message (if any)

Returns:: the latest GEOS warning message: an empty string if no warning was previoysly found.

See also:: gaiaResetGeosMsg, gaiaGetGeosErrorMsg, gaiaSetGeosErrorMsg, gaiaSetGeosWarningMsg

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaGetPointOnSurface	(	gaiaGeomCollPtr	geom,
		double *	x,
		double *	y
	)

Spatial operator: PointOnSurface.

Parameters:

geom	pointer to Geometry object.
x	on completion this variable will contain the Point X coordinate
y	on completion this variable will contain the Point Y coordinate

Returns:: 0 on failure: any other value on success

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaHausdorffDistance	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		double *	dist
	)

Calculates the Hausdorff distance intercurring between two Geometry objects.

Parameters:

geom1	pointer to first Geometry object
geom2	pointer to second Geometry object
dist	on completion this variable will contain the calculated Hausdorff distance

Returns:: 0 on failure: any other value on success.

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaHexagonalGrid	(	gaiaGeomCollPtr	geom,
		double	origin_x,
		double	origin_y,
		double	size,
		int	only_edges
	)

Utility function: HexagonalGrid.

Parameters:

geom	the Geometry to be covered by the Grid.
origin_x	the X ccordinate identifying the Grid Origin.
origin_y	the Y coordinate identifiying the Grid Origin.
size	the Grid cell-side size.
only_edges	if non-zero will return a MULTILINESTRING, otherwise it will return a MULTIPOLYGON containing hexagonal POLYGONs.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will always return a MultiPolygon
NULL will be returned if any argument is invalid.

See also:: gaiaFreeGeomColl, gaiaSquareGrid, gaiaTriangularGrid

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaHexagonalGrid()

GAIAGEO_DECLARE int gaiaIsClosed ( gaiaLinestringPtr line )

Checks if a Linestring object represents an OGC Closed Geometry.

This function only works on a single linestring - if you pass in a multi-line linestring geometry, it will return 0 (false). See gaiaIsClosedGeom for an alternative.

Parameters:

line	pointer to Linestring object.

Returns:: 0 if false; any other value if true

See also:: gaiaIsSimple, gaiaIsRing, gaiaIsValid, gaiaIsClosedGeom

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaIsClosedGeom ( gaiaGeomCollPtr geom )

Checks if a Geometry object represents an OGC Closed Linestring.

Parameters:

line	pointer to Geometry object.

Returns:: 0 if false; any other value if true

See also:: gaiaIsSimple, gaiaIsRing, gaiaIsValid, gaiaIsClosed

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaIsRing ( gaiaLinestringPtr line )

Checks if a Linestring object represents an OGC Ring Geometry.

Parameters:

line	pointer to Geometry object.

Returns:: 0 if false; any other value if true

See also:: gaiaIsSimple, gaiaIsClosed, gaiaIsValid

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaIsSimple ( gaiaGeomCollPtr geom )

Checks if a Geometry object represents an OGC Simple Geometry.

Parameters:

geom	pointer to Geometry object.

Returns:: 0 if false; any other value if true

See also:: gaiaIsClosed, gaiaIsRing, gaiaIsValid

Remarks:: GEOS support required.

GAIAGEO_DECLARE int gaiaIsValid ( gaiaGeomCollPtr geom )

Checks if a Geometry object represents an OGC Valid Geometry.

Parameters:

geom	pointer to Geometry object.

Returns:: 0 if false; any other value if true

See also:: gaiaIsSimple, gaiaIsClosed, gaiaIsRing

Remarks:: GEOS support required.

Examples:: demo2.c.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaLineInterpolateEquidistantPoints	(	gaiaGeomCollPtr	ln_geom,
		double	distance
	)

Spatial operator: Line Interpolate Equidistant Points.

Parameters:

ln_geom	the input Geometry object [expected to be of lineal type]
distance	regular distance between interpolated points

Returns:: the pointer to newly created Geometry object representing a MultiPoint; such MultiPoint always supports the M coordinate (the corresponding value representing the progressive distance for each interpolated Point). individual Points will be regularly spaced by the given distance: NULL on failure.

See also:: gaiaLineInterpolatePoint; gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaLineInterpolateEquidistantPoints()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaLineInterpolatePoint	(	gaiaGeomCollPtr	ln_geom,
		double	fraction
	)

Spatial operator: Line Interpolate Point.

Parameters:

ln_geom	the input Geometry object [expected to be of lineal type]
fraction	total length fraction [in the range 0.0 / 1.0]

Returns:: the pointer to newly created Geometry object representing a Point laying on the input Geometry and positioned at the given length fraction: NULL on failure.

See also:: gaiaLineInterpolateEquidistantPoints; gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaLineInterpolatePoint()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE double gaiaLineLocatePoint	(	gaiaGeomCollPtr	ln_geom,
		gaiaGeomCollPtr	pt_geom
	)

Determines the location of the closest Point on Linestring to the given Point.

Parameters:

ln_geom	pointer to first input Geometry object [expected to be of the lineal type].
pt_geom	pointer to second input Geometry object [expected to be a Point].

Returns:: the fraction [in the range 0.0 / 1.0] of ln_geom total length where the closest Point to pt_geom lays.

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaLineMerge ( gaiaGeomCollPtr geom )

Spatial operator: Line Merge.

Parameters:

geom	pointer to input Geometry object.

Returns:: the pointer to newly created Geometry object; NULL on failure.
if possible, this representing a reassembled Linestring or MultiLinestring.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaLineMerge()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaLinesCutAtNodes	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: Line Cut At Nodes.

Parameters:

geom1	pointer to input Geometry object [Linestring or MultiLinestring].
geom2	pointer to input Geometry object [Point or MultiPoint].

Returns:: the pointer to newly created Geometry object; NULL on failure.
if possible, any input Linestring will be split accordingly to given Node(s): no point will be interpolated, existing Linestring Vertices will be evaluated.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaLinesCutAtNodes()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaLineSubstring	(	gaiaGeomCollPtr	ln_geom,
		double	start_fraction,
		double	end_fraction
	)

Spatial operator: Line Substring.

Parameters:

ln_geom	the input Geometry object [expected to be of lineal type]
start_fraction	substring start, expressed as total length fraction [in the range 0.0 / 1.0]
end_fraction	substring end, expressed as total length fraction

Returns:: the pointer to newly created Geometry object representing a Linestring laying on the input Geometry.
this Linestring will begin (and stop) at given total length fractions. NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaLineSubstring()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaMakeValid ( gaiaGeomCollPtr geom )

Utility function: MakeValid.

Parameters:

geom	the input Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will attempt to create a valid representation of a given invalid geometry without loosing any of the input vertices.
Already-valid geometries are returned without further intervention.
NULL will be returned if the passed argument is invalid.

See also:: gaiaFreeGeomColl, gaiaMakeValidDiscarded

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaMakeValid()

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaMakeValidDiscarded ( gaiaGeomCollPtr geom )

Utility function: MakeValidDiscarded.

Parameters:

geom	the input Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will attempt to collect any invalid item (offending geometries) discarded by gaiaMakeValid while building a valid Geometry.
Saving any discarded item could be useful for a finer (manual) adjustment.
NULL will be returned if gaiaMakeValid hasn't identified any offending item to be discarded during the validation.

See also:: gaiaFreeGeomColl, gaiaMakeValid

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaMakeValidDiscarded()

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE int gaiaMaxDistance	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		double *	dist
	)

Calculates the maximum 2D distance intercurring between two Geometry objects.

Parameters:

geom1	the first Geometry object
geom2	the second Geometry object
dist	on completion this variable will contain the calculated distance

Returns:: 0 on failure: any other value on success.

See also:: gaiaGeomCollDistance, gaia3DDistance, gaia3DMaxDistance

Note:: this function computes the 2D maximum cartesian distance (Z is always ignored)

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaOffsetCurve	(	gaiaGeomCollPtr	geom,
		double	radius,
		int	points,
		int	left_right
	)

Spatial operator: Offset Curve.

Parameters:

geom	the input Geometry object
radius	the buffer's radius
points	number of points (aka vertices) to be used in order to approximate a circular arc.
left_right	if set to 1 the left-sided OffsetCurve will be returned; otherwise the right-sided one.

Returns:: the pointer to newly created Geometry object representing the OffsetCurve of input Geometry: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaOffsetCurve()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaPolygonize	(	gaiaGeomCollPtr	geom,
		int	force_multi
	)

Attempts to rearrange a generic Geometry object into a Polygon or MultiPolygon.

Parameters:

geom	the input Geometry object
force_multi	if not set to 0, then an eventual Polygon will be returned casted to MultiPolygon

Returns:: the pointer to newly created Geometry object representing a Polygon or MultiPolygon Geometry: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaPolygonize()

Remarks:: GEOS support required.

GAIAGEO_DECLARE double gaiaRadsToDegs ( double rads )

Converts and angle from Radians into Degrees.

Parameters:

rads	the angle measured in Radians.

Returns:: the angle measured in Degrees.

See also:: gaiaDegsToRads

Remarks:: PROJ.4 support required

GAIAGEO_DECLARE void gaiaResetGeosMsg ( void )

Resets the GEOS error and warning messages to an empty state.

See also:: gaiaGetGeosErrorMsg, gaiaGetGeosWarningMsg, gaiaSetGeosErrorMsg, gaiaSetGeosWarningMsg

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSegmentize	(	gaiaGeomCollPtr	geom,
		double	dist
	)

Utility function: Segmentize.

Parameters:

geom	the input Geometry object.
dist	the meximum segment length.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will return a modified geometry having no segment longer than the given distance.
Distance computation is performed in 2d only.
all Points or segments shorter than 'dist' will be returned without further intervention.
NULL will be returned if the passed argument is invalid.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSegmentize()

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE void gaiaSetGeosErrorMsg ( const char * msg )

Set the current GEOS error message.

Parameters:

msg	the error message to be set.

See also:: gaiaResetGeosMsg, gaiaGetGeosErrorMsg, gaiaGetGeosWarningMsg, gaiaSetGeosWarningMsg

Remarks:: GEOS support required.

GAIAGEO_DECLARE void gaiaSetGeosWarningMsg ( const char * msg )

Set the current GEOS warning message.

Parameters:

msg	the warning message to be set.

See also:: gaiaResetGeosMsg, gaiaGetGeosErrorMsg, gaiaGetGeosWarningMsg, gaiaSetGeosErrorMsg

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSharedPaths	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: Shared Paths.

Parameters:

geom1	pointer to first Geometry object
geom2	pointer to second Geometry object

Returns:: the pointer to newly created Geometry object representing any Share Path common to both input geometries: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSharedPaths()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaShortestLine	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2
	)

Spatial operator: Shortest Line.

Parameters:

geom1	pointer to the first Geometry object.
geom2	pointer to the second Geometry object.

Returns:: the pointer to newly created Geometry object representing a Linestring; NULL on failure.
the returned Linestring graphically represents the minimum distance intercurrinng between both input geometries.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaShortestLine()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSingleSidedBuffer	(	gaiaGeomCollPtr	geom,
		double	radius,
		int	points,
		int	left_right
	)

Spatial operator: Single Sided Buffer.

Parameters:

geom	the input Geometry object
radius	the buffer's radius
points	number of points (aka vertices) to be used in order to approximate a circular arc.
left_right	if set to 1 the left-sided Buffer will be returned; otherwise the right-sided one.

Returns:: the pointer to newly created Geometry object representing the single-sided Buffer of input Geometry: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSingleSidedBuffer()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSnap	(	gaiaGeomCollPtr	geom1,
		gaiaGeomCollPtr	geom2,
		double	tolerance
	)

Spatial operator: Shortest Line.

Parameters:

geom1	pointer to the first Geometry object.
geom2	pointer to the second Geometry object.
tolerance	approximation factor

Returns:: the pointer to newly created Geometry object; NULL on failure.
the returned Geometry represents the first input Geometry (nicely snapped to the second input Geometry, whenever is possible).

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaShortestLine()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSnapToGrid	(	gaiaGeomCollPtr	geom,
		double	origin_x,
		double	origin_y,
		double	origin_z,
		double	origin_m,
		double	size_x,
		double	size_y,
		double	size_z,
		double	size_m
	)

Utility function: SnapToGrid.

Parameters:

origin_x	the X ccordinate identifying the Grid Origin.
origin_y	the Y coordinate identifiying the Grid Origin.
size_x	Grid cell size (X axis).
size_y	Grid cell size (Y axis).
size_z	Grid cell size (Z axis).
size_m	Grid cell size (M axis).

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will return a modified geometry having all points snapped to a regular Grid defined by its origin and cell size.
Consecutive points falling on the same cell will be removed, eventually returning NULL if
output points are not enough to define a geometry of the given type.
Collapsed geometries in a collection are stripped from it.
Specify 0 as size for any dimension you don't want to snap to a grid.
NULL will be returned if the passed argument is invalid.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSnapToGrid()

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSplit	(	gaiaGeomCollPtr	input,
		gaiaGeomCollPtr	blade
	)

Utility function: Split.

Parameters:

input	the input Geometry object.
blade	the blade Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
The function supports splitting a line by point, a line by line, a polygon by line.

See also:: gaiaFreeGeomColl, gaiaSplitLeft, gaiaSplitRight

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSplit(); gaiaSplit will return both the left and the right split halves at the same time.

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSplitLeft	(	gaiaGeomCollPtr	input,
		gaiaGeomCollPtr	blade
	)

Utility function: SplitLeft.

Parameters:

input	the input Geometry object.
blade	the blade Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
The function supports splitting a line by point, a line by line, a polygon by line.

See also:: gaiaFreeGeomColl, gaiaSplit, gaiaSplitRight

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSplitLeft(); gaiaSplitLeft will only return the left split half; NULL may be eventually returned if empty.

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSplitRight	(	gaiaGeomCollPtr	input,
		gaiaGeomCollPtr	blade
	)

Utility function: SplitRight.

Parameters:

input	the input Geometry object.
blade	the blade Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
The function supports splitting a line by point, a line by line, a polygon by line.

See also:: gaiaFreeGeomColl, gaiaSplit, gaiaSplitLeft

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSplitRight(); gaiaSplitLeft will only return the right split half; NULL may be eventually returned if empty.

Remarks:: LWGEOM support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaSquareGrid	(	gaiaGeomCollPtr	geom,
		double	origin_x,
		double	origin_y,
		double	size,
		int	only_edges
	)

Utility function: SquareGrid.

Parameters:

geom	the Geometry to be covered by the Grid.
origin_x	the X ccordinate identifying the Grid Origin.
origin_y	the Y coordinate identifiying the Grid Origin.
size	the Grid cell-side size.
only_edges	if non-zero will return a MULTILINESTRING, otherwise it will return a MULTIPOLYGON containing square POLYGONs.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will always return a MultiPolygon
NULL will be returned if any argument is invalid.

See also:: gaiaFreeGeomColl, gaiaTriangularGrid, gaiaHexagonalGrid

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaSquareGrid()

GAIAGEO_DECLARE void* gaiaToGeos ( const gaiaGeomCollPtr gaia )

Converts a Geometry object into a GEOS Geometry.

Parameters:

gaia	pointer to Geometry object

Returns:: handle to GEOS Geometry

See also:: gaiaFromGeos_XY, gaiaFromGeos_XYZ, gaiaFromGeos_XYM, gaiaFromGeos_XYZM, gaiaToGeosSelective

Note:: convenience method, simply defaulting to gaiaToGeos(geom, GAIA2GEOS_ALL)

Remarks:: GEOS support required.

GAIAGEO_DECLARE void* gaiaToGeosSelective	(	const gaiaGeomCollPtr	gaia,
		int	mode
	)

Converts a Geometry object into a GEOS Geometry.

Parameters:

gaia	pointer to Geometry object
mode	one of GAIA2GEOS_ALL, GAIA2GEOS_ONLY_POINTS, GAIA2GEOS_ONLY_LINESTRINGS or GAIA2GEOS_ONLY_POLYGONS

Returns:: handle to GEOS Geometry

See also:: gaiaFromGeos_XY, gaiaFromGeos_XYZ, gaiaFromGeos_XYM, gaiaFromGeos_XYZM

Note:: if the mode argument is not GAIA2GEOS_ALL only elementary geometries of the selected type will be passed to GEOS, ignoring any other.

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaTransform	(	gaiaGeomCollPtr	org,
		char *	proj_from,
		char *	proj_to
	)

Tansforms a Geometry object into a different Reference System [aka Reprojection].

Parameters:

org	pointer to input Geometry object.
proj_from	geodetic parameters string [EPSG format] qualifying the input Reference System
proj_to	geodetic parameters string [EPSG format] qualifying the output Reference System

Returns:: the pointer to newly created Geometry object: NULL on failure.

See also:: gaiaFreeGeomColl

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaGeometryTransform()

Remarks:: PROJ.4 support required

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaTriangularGrid	(	gaiaGeomCollPtr	geom,
		double	origin_x,
		double	origin_y,
		double	size,
		int	only_edges
	)

Utility function: TriangularGrid.

Parameters:

geom	the Geometry to be covered by the Grid.
origin_x	the X ccordinate identifying the Grid Origin.
origin_y	the Y coordinate identifiying the Grid Origin.
size	the Grid cell-side size.
only_edges	if non-zero will return a MULTILINESTRING, otherwise it will return a MULTIPOLYGON containing triangular POLYGONs.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function will always return a MultiPolygon
NULL will be returned if any argument is invalid.

See also:: gaiaFreeGeomColl, gaiaSquareGrid, gaiaHexagonalGrid

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaTriangularGrid()

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaUnaryUnion ( gaiaGeomCollPtr geom )

Spatial operator: Unary Union.

Parameters:

geom	the input Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function is the same as gaiaGeometryUnion, except in that this works internally to the input Geometry itself. NULL on failure.

See also:: gaiaFreeGeomColl, gaiaGeometryUnion, gaiaUnionCascaded

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaUnaryUnion()

Remarks:: GEOS-ADVANCED support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaUnionCascaded ( gaiaGeomCollPtr geom )

Spatial operator: Union Cascaded.

Parameters:

geom	the input Geometry object.

Returns:: the pointer to newly created Geometry object: NULL on failure.
this function is similar to gaiaUnaryUnion, but it only accepts Polygons and MultiPolygons and it's now deprecated; anyway it's supported on older GEOS versions. NULL on failure.

See also:: gaiaFreeGeomColl, gaiaGeometryUnion, gaiaUnionUnion

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaUnionCascaded()

Remarks:: GEOS support required.

GAIAGEO_DECLARE gaiaGeomCollPtr gaiaVoronojDiagram	(	gaiaGeomCollPtr	geom,
		double	extra_frame_size,
		double	tolerance,
		int	only_edges
	)

Voronoj Diagram.

Parameters:

geom	pointer to input Geometry object.
extra_frame_size	percent factor expanding the BBOX of input Geometry
tolerance	optional snapping tolerance.
only_edges	if non-zero will return a MULTILINESTRING, otherwise it will return a MULTIPOLYGON.

Returns:: the pointer to newly created Geometry object: NULL on failure.
NULL will be returned if any argument is invalid.

See also:: gaiaFreeGeomColl, gaiaDelaunayTriangulation

Note:: you are responsible to destroy (before or after) any allocated Geometry, this including any Geometry returned by gaiaVoronojDiagram()

Remarks:: GEOS-TRUNK support required.

Macros

Functions

Detailed Description

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