Quantum GIS API Documentation
1.7.4
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General purpose distance and area calculator. More...
#include <qgsdistancearea.h>
Public Member Functions | |
QgsDistanceArea () | |
Constructor. | |
~QgsDistanceArea () | |
Destructor. | |
void | setProjectionsEnabled (bool flag) |
sets whether coordinates must be projected to ellipsoid before measuring | |
bool | hasCrsTransformEnabled () |
returns projections enabled flag | |
void | setSourceCrs (long srsid) |
sets source spatial reference system (by QGIS CRS) | |
Q_DECL_DEPRECATED void | setSourceEpsgCrsId (long epsgId) |
sets source spatial reference system (by EpsgCrsId) | |
void | setSourceAuthId (QString authid) |
sets source spatial reference system by authid | |
long | sourceCrs () |
returns source spatial reference system | |
bool | geographic () |
What sort of coordinate system is being used? | |
bool | setEllipsoid (const QString &ellipsoid) |
sets ellipsoid by its acronym | |
const QString & | ellipsoid () |
returns ellipsoid's acronym | |
double | ellipsoidSemiMajor () |
returns ellipsoid's semi major axis | |
double | ellipsoidSemiMinor () |
returns ellipsoid's semi minor axis | |
double | ellipsoidInverseFlattening () |
returns ellipsoid's inverse flattening | |
double | measure (QgsGeometry *geometry) |
general measurement (line distance or polygon area) | |
double | measurePerimeter (QgsGeometry *geometry) |
measures perimeter of polygon | |
double | measureLine (const QList< QgsPoint > &points) |
measures line | |
double | measureLine (const QgsPoint &p1, const QgsPoint &p2) |
measures line with one segment | |
double | measurePolygon (const QList< QgsPoint > &points) |
measures polygon area | |
double | bearing (const QgsPoint &p1, const QgsPoint &p2) |
compute bearing - in radians | |
Static Public Member Functions | |
static QString | textUnit (double value, int decimals, QGis::UnitType u, bool isArea, bool keepBaseUnit=false) |
Protected Member Functions | |
unsigned char * | measureLine (unsigned char *feature, double *area, bool hasZptr=false) |
measures line distance, line points are extracted from WKB | |
unsigned char * | measurePolygon (unsigned char *feature, double *area, double *perimeter, bool hasZptr=false) |
measures polygon area and perimeter, vertices are extracted from WKB | |
double | computeDistanceBearing (const QgsPoint &p1, const QgsPoint &p2, double *course1=NULL, double *course2=NULL) |
calculates distance from two points on ellipsoid based on inverse Vincenty's formulae | |
double | computePolygonArea (const QList< QgsPoint > &points) |
calculates area of polygon on ellipsoid algorithm has been taken from GRASS: gis/area_poly1.c | |
double | computePolygonFlatArea (const QList< QgsPoint > &points) |
void | computeAreaInit () |
precalculates some values (must be called always when changing ellipsoid) | |
Private Member Functions | |
double | getQ (double x) |
double | getQbar (double x) |
Private Attributes | |
QgsCoordinateTransform * | mCoordTransform |
used for transforming coordinates from source CRS to ellipsoid's coordinates | |
bool | mProjectionsEnabled |
indicates whether we will transform coordinates | |
long | mSourceRefSys |
id of the source spatial reference system | |
QString | mEllipsoid |
ellipsoid acronym (from table tbl_ellipsoids) | |
double | mSemiMajor |
ellipsoid parameters | |
double | mSemiMinor |
double | mInvFlattening |
double | m_QA |
double | m_QB |
double | m_QC |
double | m_QbarA |
double | m_QbarB |
double | m_QbarC |
double | m_QbarD |
double | m_AE |
double | m_Qp |
double | m_E |
double | m_TwoPI |
General purpose distance and area calculator.
Definition at line 35 of file qgsdistancearea.h.
Constructor.
Definition at line 41 of file qgsdistancearea.cpp.
References GEOCRS_ID, mCoordTransform, mProjectionsEnabled, setEllipsoid(), and setSourceCrs().
double QgsDistanceArea::bearing | ( | const QgsPoint & | p1, |
const QgsPoint & | p2 | ||
) |
compute bearing - in radians
Definition at line 515 of file qgsdistancearea.cpp.
References computeDistanceBearing(), mCoordTransform, mEllipsoid, mProjectionsEnabled, QgsCoordinateTransform::transform(), QgsPoint::x(), and QgsPoint::y().
void QgsDistanceArea::computeAreaInit | ( | ) | [protected] |
precalculates some values (must be called always when changing ellipsoid)
Definition at line 646 of file qgsdistancearea.cpp.
References getQ(), m_AE, m_E, M_PI, m_QA, m_QB, m_QbarA, m_QbarB, m_QbarC, m_QbarD, m_QC, m_Qp, m_TwoPI, mSemiMajor, and mSemiMinor.
Referenced by setEllipsoid().
double QgsDistanceArea::computeDistanceBearing | ( | const QgsPoint & | p1, |
const QgsPoint & | p2, | ||
double * | course1 = NULL , |
||
double * | course2 = NULL |
||
) | [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
Definition at line 540 of file qgsdistancearea.cpp.
References DEG2RAD, M_PI, mInvFlattening, mSemiMajor, mSemiMinor, QgsPoint::x(), and QgsPoint::y().
Referenced by bearing(), and measureLine().
double QgsDistanceArea::computePolygonArea | ( | const QList< QgsPoint > & | points | ) | [protected] |
calculates area of polygon on ellipsoid algorithm has been taken from GRASS: gis/area_poly1.c
Definition at line 674 of file qgsdistancearea.cpp.
References computePolygonFlatArea(), DEG2RAD, getQ(), getQbar(), m_AE, m_E, M_PI, m_Qp, m_TwoPI, mEllipsoid, mProjectionsEnabled, and QgsDebugMsgLevel.
Referenced by measurePolygon().
double QgsDistanceArea::computePolygonFlatArea | ( | const QList< QgsPoint > & | points | ) | [protected] |
Definition at line 729 of file qgsdistancearea.cpp.
Referenced by computePolygonArea().
const QString& QgsDistanceArea::ellipsoid | ( | ) | [inline] |
returns ellipsoid's acronym
Definition at line 68 of file qgsdistancearea.h.
Referenced by setEllipsoid().
double QgsDistanceArea::ellipsoidInverseFlattening | ( | ) | [inline] |
returns ellipsoid's inverse flattening
Definition at line 75 of file qgsdistancearea.h.
double QgsDistanceArea::ellipsoidSemiMajor | ( | ) | [inline] |
returns ellipsoid's semi major axis
Definition at line 71 of file qgsdistancearea.h.
double QgsDistanceArea::ellipsoidSemiMinor | ( | ) | [inline] |
returns ellipsoid's semi minor axis
Definition at line 73 of file qgsdistancearea.h.
bool QgsDistanceArea::geographic | ( | ) | [inline] |
What sort of coordinate system is being used?
Definition at line 62 of file qgsdistancearea.h.
double QgsDistanceArea::getQ | ( | double | x | ) | [private] |
Definition at line 624 of file qgsdistancearea.cpp.
References m_QA, m_QB, and m_QC.
Referenced by computeAreaInit(), and computePolygonArea().
double QgsDistanceArea::getQbar | ( | double | x | ) | [private] |
Definition at line 635 of file qgsdistancearea.cpp.
References m_QbarA, m_QbarB, m_QbarC, and m_QbarD.
Referenced by computePolygonArea().
bool QgsDistanceArea::hasCrsTransformEnabled | ( | ) | [inline] |
returns projections enabled flag
Definition at line 48 of file qgsdistancearea.h.
double QgsDistanceArea::measure | ( | QgsGeometry * | geometry | ) |
general measurement (line distance or polygon area)
Definition at line 180 of file qgsdistancearea.cpp.
References QgsGeometry::asWkb(), measureLine(), measurePolygon(), QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPolygon, and QGis::WKBPolygon25D.
Referenced by QgsGeometryAnalyzer::perimeterMeasure(), QgsGeometryAnalyzer::simpleMeasure(), and QgsSearchTreeNode::valueAgainst().
double QgsDistanceArea::measureLine | ( | const QList< QgsPoint > & | points | ) |
measures line
Definition at line 331 of file qgsdistancearea.cpp.
References computeDistanceBearing(), mCoordTransform, mEllipsoid, mProjectionsEnabled, QgsCoordinateTransform::transform(), and QgsLogger::warning().
Referenced by measure(), measureLine(), and measurePolygon().
double QgsDistanceArea::measureLine | ( | const QgsPoint & | p1, |
const QgsPoint & | p2 | ||
) |
measures line with one segment
Definition at line 373 of file qgsdistancearea.cpp.
References computeDistanceBearing(), mCoordTransform, mEllipsoid, mProjectionsEnabled, QgsCoordinateTransform::transform(), QgsLogger::warning(), QgsPoint::x(), and QgsPoint::y().
unsigned char * QgsDistanceArea::measureLine | ( | unsigned char * | feature, |
double * | area, | ||
bool | hasZptr = false |
||
) | [protected] |
measures line distance, line points are extracted from WKB
Definition at line 301 of file qgsdistancearea.cpp.
References measureLine(), and QgsDebugMsg.
double QgsDistanceArea::measurePerimeter | ( | QgsGeometry * | geometry | ) |
measures perimeter of polygon
Definition at line 247 of file qgsdistancearea.cpp.
References QgsGeometry::asWkb(), measurePolygon(), QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPolygon, and QGis::WKBPolygon25D.
Referenced by QgsSearchTreeNode::valueAgainst().
double QgsDistanceArea::measurePolygon | ( | const QList< QgsPoint > & | points | ) |
measures polygon area
Definition at line 487 of file qgsdistancearea.cpp.
References computePolygonArea(), mCoordTransform, mEllipsoid, mProjectionsEnabled, QgsCoordinateTransform::transform(), and QgsLogger::warning().
Referenced by measure(), and measurePerimeter().
unsigned char * QgsDistanceArea::measurePolygon | ( | unsigned char * | feature, |
double * | area, | ||
double * | perimeter, | ||
bool | hasZptr = false |
||
) | [protected] |
measures polygon area and perimeter, vertices are extracted from WKB
Definition at line 398 of file qgsdistancearea.cpp.
References computePolygonArea(), mCoordTransform, measureLine(), mEllipsoid, mProjectionsEnabled, QgsCoordinateTransform::transform(), and QgsLogger::warning().
bool QgsDistanceArea::setEllipsoid | ( | const QString & | ellipsoid | ) |
sets ellipsoid by its acronym
Definition at line 83 of file qgsdistancearea.cpp.
References computeAreaInit(), QgsCoordinateReferenceSystem::createFromProj4(), ellipsoid(), mCoordTransform, mEllipsoid, mInvFlattening, mSemiMajor, mSemiMinor, QgsDebugMsg, QgsCoordinateTransform::setDestCRS(), and QgsApplication::srsDbFilePath().
Referenced by QgsSearchTreeNode::init(), and QgsDistanceArea().
void QgsDistanceArea::setProjectionsEnabled | ( | bool | flag | ) |
sets whether coordinates must be projected to ellipsoid before measuring
Definition at line 57 of file qgsdistancearea.cpp.
References mProjectionsEnabled.
Referenced by QgsSearchTreeNode::init(), and QgsMapRenderer::setProjectionsEnabled().
void QgsDistanceArea::setSourceAuthId | ( | QString | authid | ) |
sets source spatial reference system by authid
Definition at line 76 of file qgsdistancearea.cpp.
References QgsCoordinateReferenceSystem::createFromOgcWmsCrs(), mCoordTransform, and QgsCoordinateTransform::setSourceCrs().
void QgsDistanceArea::setSourceCrs | ( | long | srsid | ) |
sets source spatial reference system (by QGIS CRS)
Definition at line 62 of file qgsdistancearea.cpp.
References QgsCoordinateReferenceSystem::createFromSrsId(), mCoordTransform, and QgsCoordinateTransform::setSourceCrs().
Referenced by QgsDistanceArea(), and QgsMapRenderer::setDestinationCrs().
void QgsDistanceArea::setSourceEpsgCrsId | ( | long | epsgId | ) |
sets source spatial reference system (by EpsgCrsId)
Definition at line 69 of file qgsdistancearea.cpp.
References QgsCoordinateReferenceSystem::createFromOgcWmsCrs(), mCoordTransform, and QgsCoordinateTransform::setSourceCrs().
long QgsDistanceArea::sourceCrs | ( | ) | [inline] |
returns source spatial reference system
Definition at line 60 of file qgsdistancearea.h.
QString QgsDistanceArea::textUnit | ( | double | value, |
int | decimals, | ||
QGis::UnitType | u, | ||
bool | isArea, | ||
bool | keepBaseUnit = false |
||
) | [static] |
Definition at line 750 of file qgsdistancearea.cpp.
References QGis::Degrees, QGis::Feet, QGis::Meters, QgsDebugMsg, and QGis::UnknownUnit.
double QgsDistanceArea::m_AE [private] |
Definition at line 158 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and computePolygonArea().
double QgsDistanceArea::m_E [private] |
Definition at line 160 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and computePolygonArea().
double QgsDistanceArea::m_QA [private] |
Definition at line 156 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQ().
double QgsDistanceArea::m_QB [private] |
Definition at line 156 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQ().
double QgsDistanceArea::m_QbarA [private] |
Definition at line 157 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQbar().
double QgsDistanceArea::m_QbarB [private] |
Definition at line 157 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQbar().
double QgsDistanceArea::m_QbarC [private] |
Definition at line 157 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQbar().
double QgsDistanceArea::m_QbarD [private] |
Definition at line 157 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQbar().
double QgsDistanceArea::m_QC [private] |
Definition at line 156 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and getQ().
double QgsDistanceArea::m_Qp [private] |
Definition at line 159 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and computePolygonArea().
double QgsDistanceArea::m_TwoPI [private] |
Definition at line 161 of file qgsdistancearea.h.
Referenced by computeAreaInit(), and computePolygonArea().
used for transforming coordinates from source CRS to ellipsoid's coordinates
Definition at line 135 of file qgsdistancearea.h.
Referenced by bearing(), measureLine(), measurePolygon(), QgsDistanceArea(), setEllipsoid(), setSourceAuthId(), setSourceCrs(), setSourceEpsgCrsId(), and ~QgsDistanceArea().
QString QgsDistanceArea::mEllipsoid [private] |
ellipsoid acronym (from table tbl_ellipsoids)
Definition at line 144 of file qgsdistancearea.h.
Referenced by bearing(), computePolygonArea(), measureLine(), measurePolygon(), and setEllipsoid().
double QgsDistanceArea::mInvFlattening [private] |
Definition at line 147 of file qgsdistancearea.h.
Referenced by computeDistanceBearing(), and setEllipsoid().
bool QgsDistanceArea::mProjectionsEnabled [private] |
indicates whether we will transform coordinates
Definition at line 138 of file qgsdistancearea.h.
Referenced by bearing(), computePolygonArea(), measureLine(), measurePolygon(), QgsDistanceArea(), and setProjectionsEnabled().
double QgsDistanceArea::mSemiMajor [private] |
ellipsoid parameters
Definition at line 147 of file qgsdistancearea.h.
Referenced by computeAreaInit(), computeDistanceBearing(), and setEllipsoid().
double QgsDistanceArea::mSemiMinor [private] |
Definition at line 147 of file qgsdistancearea.h.
Referenced by computeAreaInit(), computeDistanceBearing(), and setEllipsoid().
long QgsDistanceArea::mSourceRefSys [private] |
id of the source spatial reference system
Definition at line 141 of file qgsdistancearea.h.