QGIS API Documentation  2.18.3-Las Palmas (77b8c3d)
Public Types | Public Member Functions | Protected Slots | Protected Member Functions | List of all members
QgsTracer Class Reference

Utility class that construct a planar graph from the input vector layers and provides shortest path search for tracing of existing features. More...

#include <qgstracer.h>

Inheritance diagram for QgsTracer:
Inheritance graph
[legend]

Public Types

enum  PathError {
  ErrNone, ErrTooManyFeatures, ErrPoint1, ErrPoint2,
  ErrNoPath
}
 Possible errors that may happen when calling findShortestPath() More...
 

Public Member Functions

 QgsTracer ()
 
 ~QgsTracer ()
 
QgsCoordinateReferenceSystem destinationCrs () const
 Get CRS used for tracing. More...
 
QgsRectangle extent () const
 Get extent to which graph's features will be limited (empty extent means no limit) More...
 
QVector< QgsPointfindShortestPath (const QgsPoint &p1, const QgsPoint &p2, PathError *error=nullptr)
 Given two points, find the shortest path and return points on the way. More...
 
bool hasCrsTransformEnabled () const
 Return true if reprojection to destination CRS is enabled. More...
 
bool hasTopologyProblem () const
 Whether there was an error during graph creation due to noding exception, indicating some input data topology problems. More...
 
bool init ()
 Build the internal data structures. More...
 
bool isInitialized () const
 Whether the internal data structures have been initialized. More...
 
bool isPointSnapped (const QgsPoint &pt)
 Find out whether the point is snapped to a vertex or edge (i.e. it can be used for tracing start/stop) More...
 
QList< QgsVectorLayer * > layers () const
 Get layers used for tracing. More...
 
int maxFeatureCount () const
 Get maximum possible number of features in graph. If the number is exceeded, graph is not created. More...
 
void setCrsTransformEnabled (bool enabled)
 Set whether to do reprojection to destination CRS. More...
 
void setDestinationCrs (const QgsCoordinateReferenceSystem &crs)
 Set CRS used for tracing. More...
 
void setExtent (const QgsRectangle &extent)
 Set extent to which graph's features will be limited (empty extent means no limit) More...
 
void setLayers (const QList< QgsVectorLayer * > &layers)
 Set layers used for tracing. More...
 
void setMaxFeatureCount (int count)
 Get maximum possible number of features in graph. If the number is exceeded, graph is not created. More...
 
- Public Member Functions inherited from QObject
 QObject (QObject *parent)
 
 QObject (QObject *parent, const char *name)
 
virtual  ~QObject ()
 
bool blockSignals (bool block)
 
QObjectchild (const char *objName, const char *inheritsClass, bool recursiveSearch) const
 
const QObjectList & children () const
 
const char * className () const
 
bool connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const
 
void deleteLater ()
 
void destroyed (QObject *obj)
 
bool disconnect (const QObject *receiver, const char *method)
 
bool disconnect (const char *signal, const QObject *receiver, const char *method)
 
void dumpObjectInfo ()
 
void dumpObjectTree ()
 
QList< QByteArraydynamicPropertyNames () const
 
virtual bool event (QEvent *e)
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 
findChild (const QString &name) const
 
QList< T > findChildren (const QRegExp &regExp) const
 
QList< T > findChildren (const QString &name) const
 
bool inherits (const char *className) const
 
void insertChild (QObject *object)
 
void installEventFilter (QObject *filterObj)
 
bool isA (const char *className) const
 
bool isWidgetType () const
 
void killTimer (int id)
 
virtual const QMetaObjectmetaObject () const
 
void moveToThread (QThread *targetThread)
 
const char * name () const
 
const char * name (const char *defaultName) const
 
QString objectName () const
 
QObjectparent () const
 
QVariant property (const char *name) const
 
void removeChild (QObject *object)
 
void removeEventFilter (QObject *obj)
 
void setName (const char *name)
 
void setObjectName (const QString &name)
 
void setParent (QObject *parent)
 
bool setProperty (const char *name, const QVariant &value)
 
bool signalsBlocked () const
 
int startTimer (int interval)
 
QThreadthread () const
 

Protected Slots

void invalidateGraph ()
 Destroy the existing graph structure if any (de-initialize) More...
 

Protected Member Functions

virtual void configure ()
 Allows derived classes to setup the settings just before the tracer is initialized. More...
 
- Protected Member Functions inherited from QObject
bool checkConnectArgs (const char *signal, const QObject *object, const char *method)
 
virtual void childEvent (QChildEvent *event)
 
virtual void connectNotify (const char *signal)
 
virtual void customEvent (QEvent *event)
 
virtual void disconnectNotify (const char *signal)
 
int receivers (const char *signal) const
 
QObjectsender () const
 
int senderSignalIndex () const
 
virtual void timerEvent (QTimerEvent *event)
 

Additional Inherited Members

- Static Public Member Functions inherited from QObject
bool connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type)
 
bool connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type)
 
bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *method)
 
bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method)
 
QString tr (const char *sourceText, const char *disambiguation, int n)
 
QString trUtf8 (const char *sourceText, const char *disambiguation, int n)
 
- Static Protected Member Functions inherited from QObject
QByteArray normalizeSignalSlot (const char *signalSlot)
 
- Properties inherited from QObject
 objectName
 

Detailed Description

Utility class that construct a planar graph from the input vector layers and provides shortest path search for tracing of existing features.

Note
added in QGIS 2.14

Definition at line 38 of file qgstracer.h.

Member Enumeration Documentation

Possible errors that may happen when calling findShortestPath()

Enumerator
ErrNone 

No error.

ErrTooManyFeatures 

Max feature count threshold was reached while reading features.

ErrPoint1 

Start point cannot be joined to the graph.

ErrPoint2 

End point cannot be joined to the graph.

ErrNoPath 

Points are not connected in the graph.

Definition at line 85 of file qgstracer.h.

Constructor & Destructor Documentation

QgsTracer::QgsTracer ( )

Definition at line 455 of file qgstracer.cpp.

QgsTracer::~QgsTracer ( )

Definition at line 572 of file qgstracer.cpp.

Member Function Documentation

virtual void QgsTracer::configure ( )
inlineprotectedvirtual

Allows derived classes to setup the settings just before the tracer is initialized.

This allows the configuration to be set in a lazy way only when it is really necessary. Default implementation does nothing.

Reimplemented in QgsMapCanvasTracer.

Definition at line 106 of file qgstracer.h.

QgsCoordinateReferenceSystem QgsTracer::destinationCrs ( ) const
inline

Get CRS used for tracing.

Definition at line 56 of file qgstracer.h.

QgsRectangle QgsTracer::extent ( ) const
inline

Get extent to which graph's features will be limited (empty extent means no limit)

Definition at line 61 of file qgstracer.h.

QVector< QgsPoint > QgsTracer::findShortestPath ( const QgsPoint p1,
const QgsPoint p2,
PathError error = nullptr 
)

Given two points, find the shortest path and return points on the way.

The optional "error" argument may receive error code (PathError enum) if it is not null

Returns
array of points - trace of linestrings of other features (empty array one error)

Definition at line 674 of file qgstracer.cpp.

bool QgsTracer::hasCrsTransformEnabled ( ) const
inline

Return true if reprojection to destination CRS is enabled.

Definition at line 51 of file qgstracer.h.

bool QgsTracer::hasTopologyProblem ( ) const
inline

Whether there was an error during graph creation due to noding exception, indicating some input data topology problems.

Note
added in QGIS 2.16

Definition at line 82 of file qgstracer.h.

bool QgsTracer::init ( )

Build the internal data structures.

This may take some time depending on how big the input layers are. It is not necessary to call this method explicitly - it will be called by findShortestPath() if necessary.

Definition at line 630 of file qgstracer.cpp.

void QgsTracer::invalidateGraph ( )
protectedslot

Destroy the existing graph structure if any (de-initialize)

Definition at line 642 of file qgstracer.cpp.

bool QgsTracer::isInitialized ( ) const
inline

Whether the internal data structures have been initialized.

Definition at line 77 of file qgstracer.h.

bool QgsTracer::isPointSnapped ( const QgsPoint pt)

Find out whether the point is snapped to a vertex or edge (i.e. it can be used for tracing start/stop)

Definition at line 717 of file qgstracer.cpp.

QList<QgsVectorLayer*> QgsTracer::layers ( ) const
inline

Get layers used for tracing.

Definition at line 46 of file qgstracer.h.

int QgsTracer::maxFeatureCount ( ) const
inline

Get maximum possible number of features in graph. If the number is exceeded, graph is not created.

Definition at line 66 of file qgstracer.h.

void QgsTracer::setCrsTransformEnabled ( bool  enabled)

Set whether to do reprojection to destination CRS.

Definition at line 603 of file qgstracer.cpp.

void QgsTracer::setDestinationCrs ( const QgsCoordinateReferenceSystem crs)

Set CRS used for tracing.

Definition at line 612 of file qgstracer.cpp.

void QgsTracer::setExtent ( const QgsRectangle extent)

Set extent to which graph's features will be limited (empty extent means no limit)

Definition at line 621 of file qgstracer.cpp.

void QgsTracer::setLayers ( const QList< QgsVectorLayer * > &  layers)

Set layers used for tracing.

Definition at line 577 of file qgstracer.cpp.

void QgsTracer::setMaxFeatureCount ( int  count)
inline

Get maximum possible number of features in graph. If the number is exceeded, graph is not created.

Definition at line 68 of file qgstracer.h.


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