QGIS API Documentation  2.12.0-Lyon
Public Member Functions | Static Public Member Functions | Protected Member Functions | List of all members
QgsDistanceArea Class Reference

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 QStringellipsoid () 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...
 
Q_DECL_DEPRECATED double measure (const QgsGeometry *geometry) const
 General measurement (line distance or polygon area) More...
 
double measureArea (const QgsGeometry *geometry) const
 Measures the area of a geometry. More...
 
double measureLength (const QgsGeometry *geometry) const
 Measures the length of a geometry. More...
 
double measureLine (const QList< QgsPoint > &points) const
 measures line More...
 
double measureLine (const QgsPoint &p1, const QgsPoint &p2) const
 Measures length of line with one segment. More...
 
double measureLine (const QgsPoint &p1, const QgsPoint &p2, QGis::UnitType &units) const
 Measures length of line with one segment and returns units of distance. More...
 
double measurePerimeter (const QgsGeometry *geometry) const
 measures perimeter of polygon More...
 
double measurePolygon (const QList< QgsPoint > &points) const
 measures polygon area More...
 
QgsDistanceAreaoperator= (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 (const 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 * 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.

Definition at line 36 of file qgsdistancearea.h.

Constructor & Destructor Documentation

QgsDistanceArea::QgsDistanceArea ( )

Constructor.

Definition at line 47 of file qgsdistancearea.cpp.

QgsDistanceArea::~QgsDistanceArea ( )

Destructor.

Definition at line 64 of file qgsdistancearea.cpp.

QgsDistanceArea::QgsDistanceArea ( const QgsDistanceArea origDA)

Copy constructor.

Definition at line 58 of file qgsdistancearea.cpp.

Member Function Documentation

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

compute bearing - in radians

Definition at line 668 of file qgsdistancearea.cpp.

void QgsDistanceArea::computeAreaInit ( )
protected

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

Definition at line 841 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 775 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 693 of file qgsdistancearea.cpp.

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

uses flat / planimetric / Euclidean distance

Definition at line 770 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 876 of file qgsdistancearea.cpp.

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

Definition at line 933 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 1083 of file qgsdistancearea.cpp.

const QString& QgsDistanceArea::ellipsoid ( ) const
inline

returns ellipsoid's acronym

Definition at line 82 of file qgsdistancearea.h.

bool QgsDistanceArea::ellipsoidalEnabled ( ) const
inline

returns projections enabled flag

Definition at line 55 of file qgsdistancearea.h.

double QgsDistanceArea::ellipsoidInverseFlattening ( ) const
inline

returns ellipsoid's inverse flattening

Definition at line 89 of file qgsdistancearea.h.

double QgsDistanceArea::ellipsoidSemiMajor ( ) const
inline

returns ellipsoid's semi major axis

Definition at line 85 of file qgsdistancearea.h.

double QgsDistanceArea::ellipsoidSemiMinor ( ) const
inline

returns ellipsoid's semi minor axis

Definition at line 87 of file qgsdistancearea.h.

bool QgsDistanceArea::geographic ( ) const
inline

What sort of coordinate system is being used?

Definition at line 72 of file qgsdistancearea.h.

double QgsDistanceArea::measure ( const QgsGeometry geometry) const

General measurement (line distance or polygon area)

Deprecated:
use measureArea() or measureLength() methods instead, as this method is unpredictable for geometry collections

Definition at line 347 of file qgsdistancearea.cpp.

double QgsDistanceArea::measureArea ( const QgsGeometry geometry) const

Measures the area of a geometry.

Parameters
geometrygeometry to measure
Returns
area of geometry. For geometry collections, non surface geometries will be ignored
Note
added in QGIS 2.12
See also
measureLength()
measurePerimeter()

Definition at line 356 of file qgsdistancearea.cpp.

double QgsDistanceArea::measureLength ( const QgsGeometry geometry) const

Measures the length of a geometry.

Parameters
geometrygeometry to measure
Returns
length of geometry. For geometry collections, non curve geometries will be ignored
Note
added in QGIS 2.12
See also
measureArea()
measurePerimeter()

Definition at line 365 of file qgsdistancearea.cpp.

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

measures line

Definition at line 446 of file qgsdistancearea.cpp.

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

Measures length of line with one segment.

Parameters
p1start of line
p2end of line
Returns
distance in meters, or map units if cartesian calculation was performed

Definition at line 488 of file qgsdistancearea.cpp.

double QgsDistanceArea::measureLine ( const QgsPoint p1,
const QgsPoint p2,
QGis::UnitType units 
) const

Measures length of line with one segment and returns units of distance.

Parameters
p1start of line
p2end of line
unitswill be set to units of measure
Returns
calculated distance between points. Distance units are stored in units parameter.
Note
added in QGIS 2.12

Definition at line 494 of file qgsdistancearea.cpp.

double QgsDistanceArea::measurePerimeter ( const QgsGeometry geometry) const

measures perimeter of polygon

Definition at line 374 of file qgsdistancearea.cpp.

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

measures polygon area

Definition at line 641 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 532 of file qgsdistancearea.cpp.

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

Assignment operator.

Definition at line 70 of file qgsdistancearea.cpp.

bool QgsDistanceArea::setEllipsoid ( const QString ellipsoid)

sets ellipsoid by its acronym

Definition at line 120 of file qgsdistancearea.cpp.

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

Sets ellipsoid by supplied radii.

Definition at line 254 of file qgsdistancearea.cpp.

void QgsDistanceArea::setEllipsoidalMode ( bool  flag)

sets whether coordinates must be projected to ellipsoid before measuring

Definition at line 96 of file qgsdistancearea.cpp.

void QgsDistanceArea::setSourceAuthId ( const QString authid)

sets source spatial reference system by authid

Definition at line 113 of file qgsdistancearea.cpp.

void QgsDistanceArea::setSourceCrs ( long  srsid)

sets source spatial reference system (by QGIS CRS)

Definition at line 101 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 108 of file qgsdistancearea.cpp.

long QgsDistanceArea::sourceCrs ( ) const
inline

returns source spatial reference system

Definition at line 70 of file qgsdistancearea.h.

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

Definition at line 954 of file qgsdistancearea.cpp.


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