Provides various tools to work with geos multipolygons. More...

#include <PolygonTools.h>

Collaboration diagram for Isis::PolygonTools:

Static Public Member Functions
static geos::geom::MultiPolygon *	LatLonToXY (const geos::geom::MultiPolygon &lonLatPoly, Projection *proj)
	This method will return a geos::geom::MultiPolygon which contains the X/Y coordinates of the LonLat polygon.
static geos::geom::MultiPolygon *	XYToLatLon (const geos::geom::MultiPolygon &xYPoly, Projection *proj)
	This method will return a geos::geom::MultiPolygon which contains the (Lon,Lat) coordinates of the XY polygon.
static geos::geom::MultiPolygon *	LatLonToSampleLine (const geos::geom::MultiPolygon &lonLatPoly, UniversalGroundMap *ugm)
	This method will return a geos::geom::MultiPolygon which contains the sample/line coordinates of the Lat/Lon polygon.
static geos::geom::MultiPolygon *	CopyMultiPolygon (const geos::geom::MultiPolygon *mpolygon)
	This static method will create a deep copy of a geos::geom::MultiPolygon.
static geos::geom::MultiPolygon *	CopyMultiPolygon (const geos::geom::MultiPolygon &mpolygon)
	This static method will create a deep copy of a geos::geom::MultiPolygon.
static geos::geom::MultiPolygon *	Despike (const geos::geom::Geometry *geom)
	This method attempts to convert the geom to a MultiPolygon and then despike it.
static geos::geom::MultiPolygon *	Despike (const geos::geom::MultiPolygon *multiPoly)
	Create a new multipolygon without the spikes associated with some versions of the geos package.
static geos::geom::LinearRing *	Despike (const geos::geom::LineString *linearRing)
	Create a new LinearRing from a LineString without the spikes associated with some versions of the geos package.
static geos::geom::MultiPolygon *	To180 (geos::geom::MultiPolygon *poly360)
	Convert polygon coordinates from 360 system to 180.
static QString	ToGML (const geos::geom::MultiPolygon *mpolygon, QString idString=QString("0"))
	Write out the polygon with gml header.
static double	Thickness (const geos::geom::MultiPolygon *mpolygon)
	Calculates the thickness of a polygon using: thickness = area / max(Xextent,Yextent)**2 The provided polygon SHOULD be an XY polygon, not a lat/lon polygon, but this is not enforced.
static geos::geom::Geometry *	Intersect (const geos::geom::Geometry geom1, const geos::geom::Geometry geom2)
	This applies the geos Intersect operator.
static geos::geom::Geometry *	Difference (const geos::geom::Geometry geom1, const geos::geom::Geometry geom2)
	This method is used to subtract two polygons.
static geos::geom::MultiPolygon *	MakeMultiPolygon (const geos::geom::Geometry *geom)
	Make a geos::geom::MultiPolygon out of the components of the argument.
static QString	GetGeometryName (const geos::geom::Geometry *geom)
	This method returns the name of the type of geometry passed in.
static bool	Equal (const geos::geom::MultiPolygon poly1, const geos::geom::MultiPolygon poly2)
static bool	Equal (const geos::geom::Polygon poly1, const geos::geom::Polygon poly2)
static bool	Equal (const geos::geom::LineString lineString1, const geos::geom::LineString lineString2)
static bool	Equal (const geos::geom::Coordinate &coord1, const geos::geom::Coordinate &coord2)
static bool	Equal (const double d1, const double d2)
static geos::geom::MultiPolygon *	FixSeam (const geos::geom::MultiPolygon *poly)
static geos::geom::MultiPolygon *	FixSeam (const geos::geom::Polygon polyA, const geos::geom::Polygon polyB)
static geos::geom::Geometry *	ReducePrecision (const geos::geom::Geometry *geom, unsigned int precision)
	This method reduces the precision of the geometry to precision significant figures.
static geos::geom::MultiPolygon *	ReducePrecision (const geos::geom::MultiPolygon *poly, unsigned int precision)
	This method reduces the precision of the MultiPolygon to precision significant figures.
static geos::geom::Polygon *	ReducePrecision (const geos::geom::Polygon *poly, unsigned int precision)
	This method reduces the precision of the Polygon to precision significant figures.
static geos::geom::LinearRing *	ReducePrecision (const geos::geom::LinearRing *ring, unsigned int precision)
	This method reduces the precision of the LinearRing to precision significant figures.
static geos::geom::Coordinate *	ReducePrecision (const geos::geom::Coordinate *coord, unsigned int precision)
	This method reduces the precision of the coordinate to precision significant figures.
static double	ReducePrecision (double num, unsigned int precision)
	This method will reduce the decimal precision of the inputted num to precision decimal places.
Static Private Member Functions
static bool	IsSpiked (geos::geom::Coordinate first, geos::geom::Coordinate middle, geos::geom::Coordinate last)
	Returns true if the middle point is spiked.
static bool	TestSpiked (geos::geom::Coordinate first, geos::geom::Coordinate middle, geos::geom::Coordinate last)
	Used by IsSpiked to directionally test (first/last matter) the spike.
static geos::geom::Geometry *	FixGeometry (const geos::geom::Geometry *geom)
	This method attempts to seek out known problems with geometries and repair them.
static geos::geom::MultiPolygon *	FixGeometry (const geos::geom::MultiPolygon *poly)
	This applies the LinearRing FixGeometry method to all of the interior and exterior rings in the multipolygon.
static geos::geom::Polygon *	FixGeometry (const geos::geom::Polygon *poly)
static geos::geom::LinearRing *	FixGeometry (const geos::geom::LinearRing *ring)
	One problem we know of seems to happen when two points are right on top of each other.
static geos::geom::Geometry *	Operate (const geos::geom::Geometry geom1, const geos::geom::Geometry geom2, unsigned int opcode)
static int	DecimalPlace (double)
	This returns the location of the decimal place in the number.
Private Attributes
geos::geom::MultiPolygon *	p_polygons

Detailed Description

Provides various tools to work with geos multipolygons.

This class provides methods to that work with geos multipolygons. This includes functions to convert from one coordinate system to another and to copy multipolygons.

Author:: 2006-08-07 Stuart Sides

History:: 2006-08-07 Stuart Sides - Original version

History:: 2007-05-04 Robert Sucharski - Moved the method to output WKT from ImagePlygon class to this class. Also added method to output GML format.

History:: 2007-11-09 Tracie Sucharski - Remove ToWKT method, geos now has a method (toString) to return a WKT string. Added To180 method which converts polygon coordinates from 0/360 system to -180/180 system. If polygon was split because it crossed the 0/360 seam, the two polys coordinates are converted then merged.

History:: 2008-06-18 Steven Koechle - Fixed Documentation Errors

History:: 2008-08-18 Steven Lambright - Updated to work with geos3.0.0 instead of geos2. Mostly namespace changes.

History:: 2008-11-10 Christopher Austin - Added Thickness()

History:: 2008-11-25 Steven Koechle - Moved Despike Methods from ImageOverlapSet to PolygonTools

History:: 2008-12-01 Steven Lambright - Changed the Despike algorithm to be in more methods to clean it up, added the middle point to beginning/end of line tests to keep more data. Added "IsSpiked" and "TestSpiked."

History:: 2008-12-10 Steven Koechle - Moved MakeMultiPolygon Method from ImageOverlapSet to PolygonTools

History:: 2008-12-12 Steven Lambright - Bug fixes, cleaned up Despike/MakeMultiPolygon

History:: 2008-12-12 Steven Lambright - Renamed methods, polygon conversion methods now throw an iException if they fail, updated Despike(...)'s algorithm

History:: 2008-12-19 Steven Lambright - updated Despike(...)'s algorithm

History:: 2008-12-19 Steven Lambright - Added error to Despike (empty or invalid result).

History:: 2009-01-16 Steven Koechle - Fixed Memory Leak in LatLonToSampleLine method

History:: 2009-01-23 Steven Lambright - Added precision reduction algorithms and made the Difference and Intersect operators work in a more generic way by calling the new method Operate(...).

History:: 2009-01-28 Steven Lambright - Fixed memory leaks

History:: 2009-02-02 Stacy Alley - updated the To180 method to handle 360 multi polys that cross the -180/180 boundry. We need to return >1 polygon for these type of cases.

History:: 2009-01-28 Steven Lambright - Fixed bug in Operate(...) method when reducing precision

History:: 2009-06-09 Steven Lambright - Added a check to Equal(double,double). This never caused a problem but could have.

History:: 2011-05-31 Steven Lambright - Improved To180 (not finished). The remaining work is to remove the 0 seam from the polygons.

Definition at line 128 of file PolygonTools.h.

Member Function Documentation

geos::geom::MultiPolygon * Isis::PolygonTools::CopyMultiPolygon ( const geos::geom::MultiPolygon * mpolygon ) [static]

This static method will create a deep copy of a geos::geom::MultiPolygon.

The caller assumes responsibility for the memory associated with the new polygon.

Parameters:

mpolygon The multipolygon to be copied.

Returns:: Returns a pointer to a multipolygon which is a deep copy of the input multipolygon. This is necessary because at the time of writing the geos package does not create multipolygons when copying. It produdes geometryCollections

Definition at line 353 of file PolygonTools.cpp.

Referenced by Isis::InterestOperator::SetClipPolygon(), and Isis::ImageOverlap::SetPolygon().

geos::geom::MultiPolygon * Isis::PolygonTools::CopyMultiPolygon ( const geos::geom::MultiPolygon & mpolygon ) [static]

This static method will create a deep copy of a geos::geom::MultiPolygon.

The caller assumes responsibility for the memory associated with the new polygon.

Parameters:

mpolygon The multipolygon to be copied.

Returns:: Returns a pointer to a multipolygon which is a deep copy of the input multipolygon. This is necessary because at the time of writing the geos package does not create multipolygons when copying. It produdes geometryCollections

Definition at line 375 of file PolygonTools.cpp.

int Isis::PolygonTools::DecimalPlace ( double num ) [static, private]

This returns the location of the decimal place in the number.

This method is used as a helper method for FixGeometry(...), to help figure out how close two numbers are in significant figures.

1.0 = decimal place 1, .1 = decimal place 0, 10.0 = decimal place 2

Parameters:

num	The number to find the decimal place in

Returns:: int The decimal place relative to the first significant digit

Definition at line 1214 of file PolygonTools.cpp.

geos::geom::MultiPolygon * Isis::PolygonTools::Despike ( const geos::geom::Geometry * geom ) [static]

This method attempts to convert the geom to a MultiPolygon and then despike it.

This method does not take ownership of the argument geom. The ownership of the return value is given to the caller.

Parameters:

geom

Returns:: geos::geom::MultiPolygon*

Definition at line 565 of file PolygonTools.cpp.

geos::geom::MultiPolygon * Isis::PolygonTools::Despike ( const geos::geom::MultiPolygon * multiPoly ) [static]

Create a new multipolygon without the spikes associated with some versions of the geos package.

This method does not take ownership of the argument multiPoly. The ownership of the return value is given to the caller.

Parameters:

multiPoly The original geos::geom::MultiPolygon to be despiked.

Definition at line 585 of file PolygonTools.cpp.

References _FILEINFO_, g, and poly().

geos::geom::LinearRing * Isis::PolygonTools::Despike ( const geos::geom::LineString * lineString ) [static]

Create a new LinearRing from a LineString without the spikes associated with some versions of the geos package.

These "spikes" are created when intersections and differences are calculated.

Parameters:

lineString The original geos::geom::lineString to be despiked. This can be the lineString associated with the outside of a polygon or one of its holes.

Returns:: A pointer to a LinearRing. If the despiking causes the number of unique verticies to fall below 3, an empty LinearRing will be returned.

Definition at line 690 of file PolygonTools.cpp.

geos::geom::Geometry * Isis::PolygonTools::Difference	(	const geos::geom::Geometry *	geom1,
		const geos::geom::Geometry *	geom2
	)		`[static]`

This method is used to subtract two polygons.

Parameters:

geom1
geom2

Returns:: geos::geom::Geometry*

Definition at line 1242 of file PolygonTools.cpp.

References _FILEINFO_, and Operate().

geos::geom::Geometry * Isis::PolygonTools::FixGeometry ( const geos::geom::Geometry * geom ) [static, private]

This method attempts to seek out known problems with geometries and repair them.

Currently the only known problem is when two points lie on top of each other, which is a result of various operations. Currently only LinearRings and MultiPolygons are supported.

Parameters:

geom	The geometry to be fixed

Returns:: geos::geom::Geometry* A fixed geometry.

Definition at line 1002 of file PolygonTools.cpp.

References _FILEINFO_.

geos::geom::MultiPolygon * Isis::PolygonTools::FixGeometry ( const geos::geom::MultiPolygon * poly ) [static, private]

This applies the LinearRing FixGeometry method to all of the interior and exterior rings in the multipolygon.

See FixGeometry(LinearRing) for more explanation.

Parameters:

poly	An invalid multipolygon

Returns:: geos::geom::MultiPolygon* A possibly valid multipolygon

Definition at line 1030 of file PolygonTools.cpp.

geos::geom::LinearRing * Isis::PolygonTools::FixGeometry ( const geos::geom::LinearRing * ring ) [static, private]

One problem we know of seems to happen when two points are right on top of each other.

We're going to look for those points and remove them, then see if the linear ring is valid. Assumes input fails its isValid() test.

Point end up on top of each other for two (2) known reasons. First, Despike removes a spike that simply went back and forth. Second, the geos Intersect operator can return invalid polygons because of this problem. Every geometry thus far is being broken down into LinearRings and this method cleans those up.

Parameters:

ring	An invalid linear ring

Returns:: geos::geom::LinearRing* A possibly valid linear ring

Definition at line 1114 of file PolygonTools.cpp.

References _FILEINFO_, difference(), and min().

QString Isis::PolygonTools::GetGeometryName ( const geos::geom::Geometry * geom ) [static]

This method returns the name of the type of geometry passed in.

This is useful for error reporting (i.e. Geometry Type [...] not supported).

Parameters:

geom	The geometry to test which type it really is

Returns:: QString

Definition at line 1709 of file PolygonTools.cpp.

geos::geom::Geometry * Isis::PolygonTools::Intersect	(	const geos::geom::Geometry *	geom1,
		const geos::geom::Geometry *	geom2
	)		`[static]`

This applies the geos Intersect operator.

Due to "BinaryOp.h" having implementations in it, only one Isis object may perform these operations. If that file is included anywhere else in Isis, the library will not build! Please use this method to intersect two geometries. If the geometry is a linear ring or multi polygon, corrections may be applied if the geos intersection operator fails.

Parameters:

geom1	First geometry to intersect
geom2	Second geometry to intersect

Returns:: geos::geom::Geometry* geom1 intersected with geom2

Definition at line 877 of file PolygonTools.cpp.

References _FILEINFO_, and Operate().

Referenced by Isis::InterestOperator::FindOverlapByImageFootPrint(), and Isis::ImagePolygon::Fix360Poly().

bool Isis::PolygonTools::IsSpiked	(	geos::geom::Coordinate	first,
		geos::geom::Coordinate	middle,
		geos::geom::Coordinate	last
	)		`[static, private]`

Returns true if the middle point is spiked.

Parameters:

first
middle
last

Returns:: bool Returns true if middle point is spiked

Definition at line 765 of file PolygonTools.cpp.

geos::geom::MultiPolygon * Isis::PolygonTools::LatLonToSampleLine	(	const geos::geom::MultiPolygon &	lonLatPolygon,
		UniversalGroundMap *	ugm
	)		`[static]`

This method will return a geos::geom::MultiPolygon which contains the sample/line coordinates of the Lat/Lon polygon.

The Lat/Lon polygon must have coordinates (x direction, y direction) or (Lon,Lat).

Parameters:

lonLatPolygon	A multipolygon in (Lon,Lat order)
ugm	The UniversalGroundMap to be used to convert the Lons and Lat to Samples and Lines

Returns:: Returns a multipolygon which is the result of converting the input multipolygon from (Lon,Lat) to (Sample,Line).

Definition at line 259 of file PolygonTools.cpp.

References _FILEINFO_, g, Isis::UniversalGroundMap::Line(), poly(), Isis::UniversalGroundMap::Sample(), and Isis::UniversalGroundMap::SetUniversalGround().

Referenced by Isis::InterestOperator::InterestByPoint().

geos::geom::MultiPolygon * Isis::PolygonTools::LatLonToXY	(	const geos::geom::MultiPolygon &	lonLatPolygon,
		Projection *	projection
	)		`[static]`

This method will return a geos::geom::MultiPolygon which contains the X/Y coordinates of the LonLat polygon.

The Lat/Lon polygon must have coordinates (x direction, y direction) or (Lon,Lat).

Parameters:

lonLatPolygon	A multipolygon in (Lon,Lat) order
projection	The projection to be used to convert the Lons and Lat to X and Y

Returns:: Returns a multipolygon which is the result of converting the input multipolygon from (Lon,Lat) to (X,Y).

Definition at line 61 of file PolygonTools.cpp.

References _FILEINFO_, g, poly(), Isis::Projection::SetGround(), Isis::Projection::XCoord(), and Isis::Projection::YCoord().

geos::geom::MultiPolygon * Isis::PolygonTools::MakeMultiPolygon ( const geos::geom::Geometry * geom ) [static]

Make a geos::geom::MultiPolygon out of the components of the argument.

Create a new geos::geom::MultiPolygon out of the general geometry that is passed in. This can be useful after an intersection or some other operator on two MultiPolygons. The result of the operator is often a collection of different geometries such as points, lines, polygons... This member extracts all polygons and multipolygons into a new multipolygon. The original geometry is deleted. The resulting multipolygon is not necessarily valid.

Parameters:

geom	The geometry to be converted into a multipolygon

Definition at line 1275 of file PolygonTools.cpp.

Referenced by Isis::InterestOperator::FindOverlapByImageFootPrint(), Isis::ImagePolygon::Fix360Poly(), Isis::CubeDisplayProperties::footprint(), Isis::UniversalGroundMap::GroundRange(), Isis::ImageOverlap::ImageOverlap(), and Isis::ImagePolygon::ReadData().

geos::geom::Geometry * Isis::PolygonTools::ReducePrecision	(	const geos::geom::Geometry *	geom,
		unsigned int	precision
	)		`[static]`

This method reduces the precision of the geometry to precision significant figures.

Parameters:

geom	The geometry to reduce precision on
precision	The precision to reduce to

Returns:: geos::geom::Geometry* The lower precision geometry

Definition at line 1470 of file PolygonTools.cpp.

References _FILEINFO_.

geos::geom::MultiPolygon * Isis::PolygonTools::ReducePrecision	(	const geos::geom::MultiPolygon *	poly,
		unsigned int	precision
	)		`[static]`

This method reduces the precision of the MultiPolygon to precision significant figures.

Parameters:

poly	The MultiPolygon to reduce precision on
precision	The precision to reduce to

Returns:: geos::geom::MultiPolygon* The lower precision MultiPolygon

Definition at line 1502 of file PolygonTools.cpp.

geos::geom::Polygon * Isis::PolygonTools::ReducePrecision	(	const geos::geom::Polygon *	poly,
		unsigned int	precision
	)		`[static]`

This method reduces the precision of the Polygon to precision significant figures.

Parameters:

poly	The polygon to reduce precision on
precision	The precision to reduce to

Returns:: geos::geom::Polygon* The lower precision polygon

Definition at line 1535 of file PolygonTools.cpp.

References _FILEINFO_.

geos::geom::LinearRing * Isis::PolygonTools::ReducePrecision	(	const geos::geom::LinearRing *	ring,
		unsigned int	precision
	)		`[static]`

This method reduces the precision of the LinearRing to precision significant figures.

Parameters:

ring	The linear ring to reduce precision on
precision	The precision to reduce to

Returns:: geos::geom::LinearRing* The lower precision linear ring

Definition at line 1596 of file PolygonTools.cpp.

References _FILEINFO_.

geos::geom::Coordinate * Isis::PolygonTools::ReducePrecision	(	const geos::geom::Coordinate *	coord,
		unsigned int	precision
	)		`[static]`

This method reduces the precision of the coordinate to precision significant figures.

Parameters:

coord	The coordinate to reduce precision on
precision	The precision to reduce to

Returns:: geos::geom::Coordinate* The lower precision coordinate

Definition at line 1660 of file PolygonTools.cpp.

double Isis::PolygonTools::ReducePrecision	(	double	num,
		unsigned int	precision
	)		`[static]`

This method will reduce the decimal precision of the inputted num to precision decimal places.

Parameters:

num	The original number
precision	The new precision

Returns:: double The reduced precision number

Definition at line 1678 of file PolygonTools.cpp.

bool Isis::PolygonTools::TestSpiked	(	geos::geom::Coordinate	first,
		geos::geom::Coordinate	middle,
		geos::geom::Coordinate	last
	)		`[static, private]`

Used by IsSpiked to directionally test (first/last matter) the spike.

This method tests for spikes.

The first/last coordinate matter. If the line between the first point and middle point are the base of a triangle, with the last point as the tip, then if the base of this triangle is substantially larger than the height we have a spike (fig A). If the middle point is near the edges of the triangle, however, this is valid data (fig B/C).

(A) (B) (C) 1 1 1-2 | | | | | | 3-| | | | | | | | | 2 2-3 3

*1 is start, 2 is middle, 3 is end

Spikes are a problem because when we convert from lat/lons to meters the points get shifted relative to each other (lower points might be shifted more right then higher points, for example).

Parameters:

first
middle
last

Returns:: bool Returns true if middle point spiked given this first/last pt

Definition at line 797 of file PolygonTools.cpp.

References line, poly(), and tolerance.

double Isis::PolygonTools::Thickness ( const geos::geom::MultiPolygon * mpolygon ) [static]

Calculates the thickness of a polygon using: thickness = area / max(Xextent,Yextent)**2 The provided polygon SHOULD be an XY polygon, not a lat/lon polygon, but this is not enforced.

Parameters:

mpolygon The XY polygon to calculate the thickness of

Returns:: double The thikness of the provided polygon

Definition at line 543 of file PolygonTools.cpp.

References x, and y.

geos::geom::MultiPolygon * Isis::PolygonTools::To180 ( geos::geom::MultiPolygon * poly360 ) [static]

Convert polygon coordinates from 360 system to 180.

Parameters:

[in] poly360 (geos::geom::MultiPolygon)poly split by 360 boundary

Returns:: geos::geom::MultiPolygon Returns a 180 multi-polygon

Definition at line 446 of file PolygonTools.cpp.

References _FILEINFO_.

Referenced by Isis::MosaicSceneItem::reproject().

QString Isis::PolygonTools::ToGML	(	const geos::geom::MultiPolygon *	mpolygon,
		QString	idString = `QString("0")`
	)		`[static]`

Write out the polygon with gml header.

Parameters:

[in]	mpolygon	Polygon with lat/lon vertices
	idString	mpolygon's Id

Returns:: istrean Returns the polygon with lon,lat lon,lat format vertices and GML header

Definition at line 395 of file PolygonTools.cpp.

geos::geom::MultiPolygon * Isis::PolygonTools::XYToLatLon	(	const geos::geom::MultiPolygon &	xYPolygon,
		Projection *	projection
	)		`[static]`

This method will return a geos::geom::MultiPolygon which contains the (Lon,Lat) coordinates of the XY polygon.

The Lat/Lon polygon will have coordinates (x direction, y direction) or (Lon,Lat).

Parameters:

xYPolygon	A multipolygon in (X,Y) order
projection	The projection to be used to convert the Xs and Ys to Lon and Lats

Returns:: Returns a multipolygon which is the result of converting the input multipolygon from (X,Y) to (Lon,Lat).

Definition at line 167 of file PolygonTools.cpp.

References _FILEINFO_, g, Isis::Projection::Latitude(), Isis::Projection::Longitude(), poly(), and Isis::Projection::SetWorld().

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

src/base/objs/PolygonTools/PolygonTools.h
src/base/objs/PolygonTools/PolygonTools.cpp

Static Public Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation