General purpose distance and area calculator. More...

#include <qgsdistancearea.h>

Public Member Functions
	QgsDistanceArea ()
	Constructor. More...

	QgsDistanceArea (const QgsDistanceArea &origDA)
	Copy constructor. More...

	~QgsDistanceArea ()
	Destructor. More...

double	bearing (const QgsPoint &p1, const QgsPoint &p2) const
	compute bearing - in radians More...

void	convertMeasurement (double &measure, QGis::UnitType &measureUnits, QGis::UnitType displayUnits, bool isArea) const
	Helper for conversion between physical units. More...

const QString &	ellipsoid () const
	returns ellipsoid's acronym More...

bool	ellipsoidalEnabled () const
	returns projections enabled flag More...

double	ellipsoidInverseFlattening () const
	returns ellipsoid's inverse flattening More...

double	ellipsoidSemiMajor () const
	returns ellipsoid's semi major axis More...

double	ellipsoidSemiMinor () const
	returns ellipsoid's semi minor axis More...

bool	geographic () const
	What sort of coordinate system is being used? More...

double	measure (const QgsGeometry *geometry) const
	general measurement (line distance or polygon area) More...

double	measureLine (const QList< QgsPoint > &points) const
	measures line More...

double	measureLine (const QgsPoint &p1, const QgsPoint &p2) const
	measures line with one segment More...

double	measurePerimeter (const QgsGeometry *geometry) const
	measures perimeter of polygon More...

double	measurePolygon (const QList< QgsPoint > &points) const
	measures polygon area More...

QgsDistanceArea &	operator= (const QgsDistanceArea &origDA)
	Assignment operator. More...

bool	setEllipsoid (const QString &ellipsoid)
	sets ellipsoid by its acronym More...

bool	setEllipsoid (double semiMajor, double semiMinor)
	Sets ellipsoid by supplied radii. More...

void	setEllipsoidalMode (bool flag)
	sets whether coordinates must be projected to ellipsoid before measuring More...

void	setSourceAuthId (QString authid)
	sets source spatial reference system by authid More...

void	setSourceCrs (long srsid)
	sets source spatial reference system (by QGIS CRS) More...

void	setSourceCrs (const QgsCoordinateReferenceSystem &srcCRS)
	Sets source spatial reference system (by QGIS CRS) More...

long	sourceCrs () const
	returns source spatial reference system More...

Static Public Member Functions
static QString	textUnit (double value, int decimals, QGis::UnitType u, bool isArea, bool keepBaseUnit=false)

Protected Member Functions
void	computeAreaInit ()
	precalculates some values (must be called always when changing ellipsoid) More...

double	computeDistance (const QList< QgsPoint > &points) const
	calculate distance with given coordinates (does not do a transform anymore) More...

double	computeDistanceBearing (const QgsPoint &p1, const QgsPoint &p2, double course1=NULL, double course2=NULL) const
	calculates distance from two points on ellipsoid based on inverse Vincenty's formulae More...

double	computeDistanceFlat (const QgsPoint &p1, const QgsPoint &p2) const
	uses flat / planimetric / Euclidean distance More...

double	computePolygonArea (const QList< QgsPoint > &points) const
	calculates area of polygon on ellipsoid algorithm has been taken from GRASS: gis/area_poly1.c More...

double	computePolygonFlatArea (const QList< QgsPoint > &points) const

const unsigned char *	measureLine (const unsigned char feature, double area, bool hasZptr=false) const
	measures line distance, line points are extracted from WKB More...

const unsigned char *	measurePolygon (const unsigned char feature, double area, double *perimeter, bool hasZptr=false) const
	measures polygon area and perimeter, vertices are extracted from WKB More...

Detailed Description

General purpose distance and area calculator.

calculations are done on ellipsoid
it's possible to pass points/features in any CRS, coordinates are transformed
two options how to use it
- use measure() takes QgsGeometry as a parameter and calculates distance or area
- use directly measureLine(), measurePolygon() which take list of QgsPoints (both cases transform the coordinates from source CRS to the ellipse coords)
returned values are in meters resp. square meters

Definition at line 34 of file qgsdistancearea.h.

Constructor & Destructor Documentation

QgsDistanceArea::QgsDistanceArea ( )

Constructor.

Definition at line 42 of file qgsdistancearea.cpp.

QgsDistanceArea::~QgsDistanceArea ( )

Destructor.

Definition at line 58 of file qgsdistancearea.cpp.

QgsDistanceArea::QgsDistanceArea ( const QgsDistanceArea & origDA )

Copy constructor.

Definition at line 53 of file qgsdistancearea.cpp.

Member Function Documentation

double QgsDistanceArea::bearing	(	const QgsPoint &	p1,
		const QgsPoint &	p2
	)		const

compute bearing - in radians

Definition at line 621 of file qgsdistancearea.cpp.

void QgsDistanceArea::computeAreaInit ( )

protected

precalculates some values (must be called always when changing ellipsoid)

Definition at line 794 of file qgsdistancearea.cpp.

double QgsDistanceArea::computeDistance ( const QList< QgsPoint > & points ) const

protected

calculate distance with given coordinates (does not do a transform anymore)

Definition at line 728 of file qgsdistancearea.cpp.

double QgsDistanceArea::computeDistanceBearing	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		double *	course1 = `NULL`,
		double *	course2 = `NULL`
	)		const

protected

calculates distance from two points on ellipsoid based on inverse Vincenty's formulae

Points p1 and p2 are expected to be in degrees and in currently used ellipsoid

Note: if course1 is not NULL, bearing (in radians) from first point is calculated (the same for course2)

Returns: distance in meters

Definition at line 646 of file qgsdistancearea.cpp.

double QgsDistanceArea::computeDistanceFlat	(	const QgsPoint &	p1,
		const QgsPoint &	p2
	)		const

protected

uses flat / planimetric / Euclidean distance

Definition at line 723 of file qgsdistancearea.cpp.

double QgsDistanceArea::computePolygonArea ( const QList< QgsPoint > & points ) const

protected

calculates area of polygon on ellipsoid algorithm has been taken from GRASS: gis/area_poly1.c

Definition at line 829 of file qgsdistancearea.cpp.

double QgsDistanceArea::computePolygonFlatArea ( const QList< QgsPoint > & points ) const

protected

Definition at line 886 of file qgsdistancearea.cpp.

void QgsDistanceArea::convertMeasurement	(	double &	measure,
		QGis::UnitType &	measureUnits,
		QGis::UnitType	displayUnits,
		bool	isArea
	)		const

Helper for conversion between physical units.

Definition at line 1036 of file qgsdistancearea.cpp.

const QString& QgsDistanceArea::ellipsoid ( ) const

inline

returns ellipsoid's acronym

Definition at line 80 of file qgsdistancearea.h.

bool QgsDistanceArea::ellipsoidalEnabled ( ) const

inline

returns projections enabled flag

Definition at line 53 of file qgsdistancearea.h.

double QgsDistanceArea::ellipsoidInverseFlattening ( ) const

inline

returns ellipsoid's inverse flattening

Definition at line 87 of file qgsdistancearea.h.

double QgsDistanceArea::ellipsoidSemiMajor ( ) const

inline

returns ellipsoid's semi major axis

Definition at line 83 of file qgsdistancearea.h.

double QgsDistanceArea::ellipsoidSemiMinor ( ) const

inline

returns ellipsoid's semi minor axis

Definition at line 85 of file qgsdistancearea.h.

bool QgsDistanceArea::geographic ( ) const

inline

What sort of coordinate system is being used?

Definition at line 70 of file qgsdistancearea.h.

double QgsDistanceArea::measure ( const QgsGeometry * geometry ) const

general measurement (line distance or polygon area)

Definition at line 259 of file qgsdistancearea.cpp.

double QgsDistanceArea::measureLine ( const QList< QgsPoint > & points ) const

measures line

Definition at line 421 of file qgsdistancearea.cpp.

double QgsDistanceArea::measureLine	(	const QgsPoint &	p1,
		const QgsPoint &	p2
	)		const

measures line with one segment

Definition at line 463 of file qgsdistancearea.cpp.

const unsigned char * QgsDistanceArea::measureLine	(	const unsigned char *	feature,
		double *	area,
		bool	hasZptr = `false`
	)		const

protected

measures line distance, line points are extracted from WKB

Definition at line 394 of file qgsdistancearea.cpp.

double QgsDistanceArea::measurePerimeter ( const QgsGeometry * geometry ) const

measures perimeter of polygon

Definition at line 334 of file qgsdistancearea.cpp.

double QgsDistanceArea::measurePolygon ( const QList< QgsPoint > & points ) const

measures polygon area

Definition at line 594 of file qgsdistancearea.cpp.

const unsigned char * QgsDistanceArea::measurePolygon	(	const unsigned char *	feature,
		double *	area,
		double *	perimeter,
		bool	hasZptr = `false`
	)		const

protected

measures polygon area and perimeter, vertices are extracted from WKB

Definition at line 499 of file qgsdistancearea.cpp.

QgsDistanceArea & QgsDistanceArea::operator= ( const QgsDistanceArea & origDA )

Assignment operator.

Definition at line 64 of file qgsdistancearea.cpp.

bool QgsDistanceArea::setEllipsoid ( const QString & ellipsoid )

sets ellipsoid by its acronym

Definition at line 113 of file qgsdistancearea.cpp.

bool QgsDistanceArea::setEllipsoid	(	double	semiMajor,
		double	semiMinor
	)

Sets ellipsoid by supplied radii.

Definition at line 247 of file qgsdistancearea.cpp.

void QgsDistanceArea::setEllipsoidalMode ( bool flag )

sets whether coordinates must be projected to ellipsoid before measuring

Definition at line 89 of file qgsdistancearea.cpp.

void QgsDistanceArea::setSourceAuthId ( QString authid )

sets source spatial reference system by authid

Definition at line 106 of file qgsdistancearea.cpp.

void QgsDistanceArea::setSourceCrs ( long srsid )

sets source spatial reference system (by QGIS CRS)

Definition at line 94 of file qgsdistancearea.cpp.

void QgsDistanceArea::setSourceCrs ( const QgsCoordinateReferenceSystem & srcCRS )

Sets source spatial reference system (by QGIS CRS)

Note: : missing in Python bindings in QGIS < 2.2

Definition at line 101 of file qgsdistancearea.cpp.

long QgsDistanceArea::sourceCrs ( ) const

inline

returns source spatial reference system

Definition at line 68 of file qgsdistancearea.h.

QString QgsDistanceArea::textUnit	(	double	value,
		int	decimals,
		QGis::UnitType	u,
		bool	isArea,
		bool	keepBaseUnit = `false`
	)

static

Definition at line 907 of file qgsdistancearea.cpp.

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

/tmp/buildd/qgis-2.10.1+git20150822+dd4475c+20trusty/src/core/qgsdistancearea.h
/tmp/buildd/qgis-2.10.1+git20150822+dd4475c+20trusty/src/core/qgsdistancearea.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation