Rename QgsGeometry::isEmpty to isNull

Differentiates missing geometries from empty geometries (eg
empty geometry collections)

doc/api_break.dox

@@ -1044,8 +1044,10 @@ QgsGeometry        {#qgis_api_break_3_0_QgsGeometry}
 
 - All QgsGeometry methods now accept geometry references instead of pointers, and return a QgsGeometry
 value instead of a pointer. The biggest impact with this change is that PyQGIS code should not compare a geometry
-result to None, but instead either use a boolean test (`if g.buffer(10):`) or explicitly use the isEmpty()
+result to None, but instead either use a boolean test (`if g.buffer(10):`) or explicitly use the isNull()
 method to determine if a geometry is valid.
+- isEmpty() was renamed to isNull() to differentiate a missing geometry from a geometry which is empty (eg an
+empty geometry collection)
 - wkbSize() and asWkb() has been replaced by exportToWkb(). WKB representation is no longer cached within QgsGeometry
 - asGeos() has been replaced by exportToGeos(). GEOS representation is no longer cached within QgsGeometry
 - int addPart( const QList<QgsPoint> &points, QgsWkbTypes::GeometryType geomType ) has been renamed to addPoints

python/core/geometry/qgsgeometry.sip

@@ -57,12 +57,7 @@ class QgsGeometry
      */
     void setGeometry( QgsAbstractGeometry* geometry /Transfer/ );
 
-    /** Returns true if the geometry is empty (ie, contains no underlying geometry
-     * accessible via @link geometry @endlink).
-     * @see geometry
-     * @note added in QGIS 2.10
-     */
-    bool isEmpty() const;
+    bool isNull() const;
 
     /** Creates a new geometry from a WKT string */
     static QgsGeometry fromWkt( const QString& wkt );

python/plugins/processing/algs/qgis/CheckValidity.py

@@ -137,7 +137,7 @@ def doCheck(self, feedback):
             attrs = inFeat.attributes()
 
             valid = True
-            if not geom.isEmpty() and not geom.isGeosEmpty():
+            if not geom.isNull() and not geom.isGeosEmpty():
                 errors = list(geom.validateGeometry())
                 if errors:
                     # QGIS method return a summary at the end

python/plugins/processing/algs/qgis/Delaunay.py

@@ -82,7 +82,7 @@ def processAlgorithm(self, feedback):
         total = 100.0 / len(features)
         for current, inFeat in enumerate(features):
             geom = QgsGeometry(inFeat.geometry())
-            if geom.isEmpty():
+            if geom.isNull():
                 continue
             if geom.isMultipart():
                 points = geom.asMultiPoint()

python/plugins/processing/algs/qgis/Dissolve.py

@@ -93,7 +93,7 @@ def processAlgorithm(self, feedback):
                     first = False
 
                 tmpInGeom = inFeat.geometry()
-                if tmpInGeom.isEmpty() or tmpInGeom.isGeosEmpty():
+                if tmpInGeom.isNull() or tmpInGeom.isGeosEmpty():
                     continue
 
                 errors = tmpInGeom.validateGeometry()

python/plugins/processing/algs/qgis/PolygonCentroids.py

@@ -80,7 +80,7 @@ def processAlgorithm(self, feedback):
             inGeom = feat.geometry()
             attrs = feat.attributes()
 
-            if inGeom.isEmpty():
+            if inGeom.isNull():
                 outGeom = QgsGeometry(None)
             else:
                 outGeom = QgsGeometry(inGeom.centroid())

python/plugins/processing/algs/qgis/ReverseLineDirection.py

@@ -65,7 +65,7 @@ def processAlgorithm(self, feedback):
             attrs = inFeat.attributes()
 
             outGeom = None
-            if not inGeom.isEmpty():
+            if not inGeom.isNull():
                 reversedLine = inGeom.geometry().reversed()
                 if not reversedLine:
                     raise GeoAlgorithmExecutionException(

python/plugins/processing/algs/qgis/SplitWithLines.py

@@ -127,7 +127,7 @@ def processAlgorithm(self, feedback):
                         while len(inGeoms) > 0:
                             inGeom = inGeoms.pop()
 
-                            if inGeom.isEmpty(): # this has been encountered and created a run-time error
+                            if inGeom.isNull(): # this has been encountered and created a run-time error
                                 continue
 
                             if split_geom_engine.intersects(inGeom.geometry()):

src/analysis/interpolation/qgsinterpolator.cpp

@@ -105,7 +105,7 @@ int QgsInterpolator::cacheBaseData()
 
 int QgsInterpolator::addVerticesToCache( const QgsGeometry& geom, bool zCoord, double attributeValue )
 {
-  if ( geom.isEmpty() )
+  if ( geom.isNull() )
     return 1;
 
   bool hasZValue = false;

src/analysis/interpolation/qgstininterpolator.cpp

@@ -175,7 +175,7 @@ int QgsTINInterpolator::insertData( QgsFeature* f, bool zCoord, int attr, InputT
 
   QgsGeometry g = f->geometry();
   {
-    if ( g.isEmpty() )
+    if ( g.isNull() )
     {
       return 2;
     }

src/analysis/openstreetmap/qgsosmdatabase.cpp

@@ -504,7 +504,7 @@ void QgsOSMDatabase::exportSpatiaLiteWays( bool closed, const QString& tableName
         sqlite3_bind_null( stmtInsert, ++col );
     }
 
-    if ( !geom.isEmpty() )
+    if ( !geom.isNull() )
     {
       QByteArray wkb( geom.exportToWkb() );
       sqlite3_bind_blob( stmtInsert, ++col, wkb.constData(), wkb.length(), SQLITE_STATIC );

src/analysis/raster/qgskde.cpp

@@ -110,7 +110,7 @@ QgsKernelDensityEstimation::Result QgsKernelDensityEstimation::prepare()
 QgsKernelDensityEstimation::Result QgsKernelDensityEstimation::addFeature( const QgsFeature& feature )
 {
   QgsGeometry featureGeometry = feature.geometry();
-  if ( featureGeometry.isEmpty() )
+  if ( featureGeometry.isNull() )
   {
     return Success;
   }

src/analysis/vector/qgsgeometryanalyzer.cpp

@@ -475,7 +475,7 @@ bool QgsGeometryAnalyzer::convexHull( QgsVectorLayer* layer, const QString& shap
         ++jt;
       }
       QList<double> values;
-      if ( dissolveGeometry.isEmpty() )
+      if ( dissolveGeometry.isNull() )
       {
         QgsDebugMsg( "no dissolved geometry - should not happen" );
         return false;
@@ -520,7 +520,7 @@ bool QgsGeometryAnalyzer::convexHull( QgsVectorLayer* layer, const QString& shap
         ++jt;
       }
       QList<double> values;
-      if ( dissolveGeometry.isEmpty() )
+      if ( dissolveGeometry.isNull() )
       {
         QgsDebugMsg( "no dissolved geometry - should not happen" );
         return false;
@@ -705,7 +705,7 @@ QgsGeometry QgsGeometryAnalyzer::dissolveFeature( const QgsFeature& f, const Qgs
 
   QgsGeometry featureGeometry = f.geometry();
 
-  if ( dissolveInto.isEmpty() )
+  if ( dissolveInto.isNull() )
   {
     return featureGeometry;
   }
@@ -810,7 +810,7 @@ bool QgsGeometryAnalyzer::buffer( QgsVectorLayer* layer, const QString& shapefil
   if ( dissolve )
   {
     QgsFeature dissolveFeature;
-    if ( dissolveGeometry.isEmpty() )
+    if ( dissolveGeometry.isNull() )
     {
       QgsDebugMsg( "no dissolved geometry - should not happen" );
       return false;
@@ -967,7 +967,7 @@ bool QgsGeometryAnalyzer::eventLayer( QgsVectorLayer* lineLayer, QgsVectorLayer*
         lrsGeom = locateBetweenMeasures( measure1, measure2, featureIdIt->geometry() );
       }
 
-      if ( !lrsGeom.isEmpty() )
+      if ( !lrsGeom.isNull() )
       {
         ++nOutputFeatures;
         addEventLayerFeature( fet, lrsGeom, featureIdIt->geometry(), fileWriter, memoryProviderFeatures, offsetField, offsetScale, forceSingleGeometry );
@@ -995,7 +995,7 @@ bool QgsGeometryAnalyzer::eventLayer( QgsVectorLayer* lineLayer, QgsVectorLayer*
 void QgsGeometryAnalyzer::addEventLayerFeature( QgsFeature& feature, const QgsGeometry& geom, const QgsGeometry& lineGeom, QgsVectorFileWriter* fileWriter, QgsFeatureList& memoryFeatures,
     int offsetField, double offsetScale, bool forceSingleType )
 {
-  if ( geom.isEmpty() )
+  if ( geom.isNull() )
   {
     return;
   }
@@ -1020,7 +1020,7 @@ void QgsGeometryAnalyzer::addEventLayerFeature( QgsFeature& feature, const QgsGe
       double offsetVal = feature.attribute( offsetField ).toDouble();
       offsetVal *= offsetScale;
       newGeom = createOffsetGeometry( *geomIt, lineGeom, offsetVal );
-      if ( newGeom.isEmpty() )
+      if ( newGeom.isNull() )
       {
         continue;
       }
@@ -1040,7 +1040,7 @@ void QgsGeometryAnalyzer::addEventLayerFeature( QgsFeature& feature, const QgsGe
 
 QgsGeometry QgsGeometryAnalyzer::createOffsetGeometry( const QgsGeometry& geom, const QgsGeometry& lineGeom, double offset )
 {
-  if ( !geom || lineGeom.isEmpty() )
+  if ( !geom || lineGeom.isNull() )
   {
     return QgsGeometry();
   }
@@ -1147,7 +1147,7 @@ QgsPoint QgsGeometryAnalyzer::createPointOffset( double x, double y, double dist
 
 QgsGeometry QgsGeometryAnalyzer::locateBetweenMeasures( double fromMeasure, double toMeasure, const QgsGeometry& lineGeom )
 {
-  if ( lineGeom.isEmpty() )
+  if ( lineGeom.isNull() )
   {
     return QgsGeometry();
   }
@@ -1189,7 +1189,7 @@ QgsGeometry QgsGeometryAnalyzer::locateBetweenMeasures( double fromMeasure, doub
 
 QgsGeometry QgsGeometryAnalyzer::locateAlongMeasure( double measure, const QgsGeometry& lineGeom )
 {
-  if ( lineGeom.isEmpty() )
+  if ( lineGeom.isNull() )
   {
     return QgsGeometry();
   }

src/analysis/vector/qgsgeometrysnapper.cpp

@@ -475,7 +475,7 @@ QgsFeatureList QgsGeometrySnapper::snapFeatures( const QgsFeatureList& features,
 
 void QgsGeometrySnapper::processFeature( QgsFeature& feature, double snapTolerance, SnapMode mode )
 {
-  if ( !feature.geometry().isEmpty() )
+  if ( !feature.geometry().isNull() )
     feature.setGeometry( snapGeometry( feature.geometry(), snapTolerance, mode ) );
 }
 

src/analysis/vector/qgstransectsample.cpp

@@ -172,7 +172,7 @@ int QgsTransectSample::createSample( QProgressDialog* pd )
     //find baseline for strata
     QVariant strataId = fet.attribute( mStrataIdAttribute );
     QgsGeometry baselineGeom = findBaselineGeometry( strataId.isValid() ? strataId : -1 );
-    if ( baselineGeom.isEmpty() )
+    if ( baselineGeom.isNull() )
     {
       continue;
     }
@@ -218,7 +218,7 @@ int QgsTransectSample::createSample( QProgressDialog* pd )
       double randomPosition = (( double )mt_rand() / MD_RAND_MAX ) * clippedBaseline.length();
       QgsGeometry samplePoint = clippedBaseline.interpolate( randomPosition );
       ++nIterations;
-      if ( samplePoint.isEmpty() )
+      if ( samplePoint.isNull() )
       {
         continue;
       }
@@ -252,7 +252,7 @@ int QgsTransectSample::createSample( QProgressDialog* pd )
       lineFarAway << sampleQgsPoint << ptFarAway;
       QgsGeometry lineFarAwayGeom = QgsGeometry::fromPolyline( lineFarAway );
       QgsGeometry lineClipStratum = lineFarAwayGeom.intersection( strataGeom );
-      if ( lineClipStratum.isEmpty() )
+      if ( lineClipStratum.isNull() )
       {
         continue;
       }
@@ -268,7 +268,7 @@ int QgsTransectSample::createSample( QProgressDialog* pd )
            || lineClipStratum.wkbType() == QgsWkbTypes::MultiLineString25D )
       {
         QgsGeometry singleLine = closestMultilineElement( sampleQgsPoint, lineClipStratum );
-        if ( !singleLine.isEmpty() )
+        if ( !singleLine.isNull() )
         {
           lineClipStratum = singleLine;
         }
@@ -351,13 +351,13 @@ QgsGeometry QgsTransectSample::findBaselineGeometry( const QVariant& strataId )
 bool QgsTransectSample::otherTransectWithinDistance( const QgsGeometry& geom, double minDistLayerUnit, double minDistance, QgsSpatialIndex& sIndex,
     const QMap< QgsFeatureId, QgsGeometry >& lineFeatureMap, QgsDistanceArea& da )
 {
-  if ( geom.isEmpty() )
+  if ( geom.isNull() )
   {
     return false;
   }
 
   QgsGeometry buffer = geom.buffer( minDistLayerUnit, 8 );
-  if ( buffer.isEmpty() )
+  if ( buffer.isNull() )
   {
     return false;
   }
@@ -557,7 +557,7 @@ QgsGeometry* QgsTransectSample::clipBufferLine( const QgsGeometry& stratumGeom,
   {
     //int verticesBefore = usedBaseline->asMultiPolyline().count();
     usedBaseline = clippedBaseline->simplify( mBaselineSimplificationTolerance );
-    if ( usedBaseline.isEmpty() )
+    if ( usedBaseline.isNull() )
     {
       return nullptr;
     }
@@ -576,7 +576,7 @@ QgsGeometry* QgsTransectSample::clipBufferLine( const QgsGeometry& stratumGeom,
   {
     //loop with tolerance: create buffer, convert buffer to line, clip line by stratum, test if result is (single) line
     QgsGeometry clipBaselineBuffer = usedBaseline.buffer( currentBufferDist, 8 );
-    if ( clipBaselineBuffer.isEmpty() )
+    if ( clipBaselineBuffer.isNull() )
     {
       continue;
     }
@@ -621,7 +621,7 @@ QgsGeometry* QgsTransectSample::clipBufferLine( const QgsGeometry& stratumGeom,
     }
     bufferLineClipped = bufferLine.intersection( stratumGeom );
 
-    if ( bufferLineClipped.isEmpty() && bufferLineClipped.type() == QgsWkbTypes::LineGeometry )
+    if ( bufferLineClipped.isNull() && bufferLineClipped.type() == QgsWkbTypes::LineGeometry )
     {
       //if stratumGeom is a multipolygon, bufferLineClipped must intersect each part
       bool bufferLineClippedIntersectsStratum = true;

src/analysis/vector/qgszonalstatistics.cpp

@@ -490,11 +490,11 @@ void QgsZonalStatistics::statisticsFromPreciseIntersection( void* band, const Qg
         continue;
 
       pixelRectGeometry = QgsGeometry::fromRect( QgsRectangle( currentX - hCellSizeX, currentY - hCellSizeY, currentX + hCellSizeX, currentY + hCellSizeY ) );
-      if ( !pixelRectGeometry.isEmpty() )
+      if ( !pixelRectGeometry.isNull() )
       {
         //intersection
         QgsGeometry intersectGeometry = pixelRectGeometry.intersection( poly );
-        if ( !intersectGeometry.isEmpty() )
+        if ( !intersectGeometry.isNull() )
         {
           double intersectionArea = intersectGeometry.area();
           if ( intersectionArea >= 0.0 )

src/app/dwg/qgsdwgimporter.cpp

@@ -2577,7 +2577,7 @@ bool QgsDwgImporter::expandInserts( QString &error )
     }
 
     QgsGeometry g( QgsOgrUtils::ogrGeometryToQgsGeometry( ogrG ) );
-    if ( g.isEmpty() )
+    if ( g.isNull() )
     {
       QgsDebugMsg( QString( "%1: could not copy geometry" ).arg( OGR_F_GetFID( insert ) ) );
       continue;
@@ -2668,7 +2668,7 @@ bool QgsDwgImporter::expandInserts( QString &error )
         }
 
         QgsGeometry g( QgsOgrUtils::ogrGeometryToQgsGeometry( ogrG ) );
-        if ( g.isEmpty() )
+        if ( g.isNull() )
         {
           QgsDebugMsg( QString( "%1: could not copy geometry" ).arg( fid ) );
           continue;

src/app/nodetool/qgsmaptoolnodetool.cpp

@@ -660,7 +660,7 @@ void QgsMapToolNodeTool::deleteNodeSelection()
 
     mSelectedFeature->deleteSelectedVertexes();
 
-    if ( mSelectedFeature->geometry()->isEmpty() )
+    if ( mSelectedFeature->geometry()->isNull() )
     {
       emit messageEmitted( tr( "Geometry has been cleared. Use the add part tool to set geometry for this feature." ) );
     }

src/app/qgisapp.cpp

@@ -6661,10 +6661,10 @@ QgsGeometry QgisApp::unionGeometries( const QgsVectorLayer* vl, QgsFeatureList&
     }
     progress.setValue( i );
     QgsGeometry currentGeom = featureList.at( i ).geometry();
-    if ( !currentGeom.isEmpty() )
+    if ( !currentGeom.isNull() )
     {
       unionGeom = unionGeom.combine( currentGeom );
-      if ( unionGeom.isEmpty() )
+      if ( unionGeom.isNull() )
       {
         QApplication::restoreOverrideCursor();
         return QgsGeometry();
@@ -7193,7 +7193,7 @@ void QgisApp::mergeSelectedFeatures()
   QgsFeatureList featureList = vl->selectedFeatures();  //get QList<QgsFeature>
   bool canceled;
   QgsGeometry unionGeom = unionGeometries( vl, featureList, canceled );
-  if ( unionGeom.isEmpty() )
+  if ( unionGeom.isNull() )
   {
     if ( !canceled )
     {
@@ -7229,7 +7229,7 @@ void QgisApp::mergeSelectedFeatures()
     bool canceled;
     QgsFeatureList featureListAfter = vl->selectedFeatures();
     unionGeom = unionGeometries( vl, featureListAfter, canceled );
-    if ( unionGeom.isEmpty() )
+    if ( unionGeom.isNull() )
     {
       if ( !canceled )
       {
@@ -7585,7 +7585,7 @@ void QgisApp::editPaste( QgsMapLayer *destinationLayer )
       if ( destType != QgsWkbTypes::UnknownGeometry )
       {
         QgsGeometry newGeometry = geom.convertToType( destType, destIsMulti );
-        if ( newGeometry.isEmpty() )
+        if ( newGeometry.isNull() )
         {
           continue;
         }