length3D function: handle multipart geometries

qgis · Feb 24, 2021 · 3ebf915 · 3ebf915
1 parent d7167e4
commit 3ebf915
Showing 1 changed file with 17 additions and 1 deletion.
diff --git a/src/core/expression/qgsexpressionfunction.cpp b/src/core/expression/qgsexpressionfunction.cpp
@@ -1364,7 +1364,23 @@ static QVariant fcnLength3D( const QVariantList &values, const QgsExpressionCont
   if ( geom.type() != QgsWkbTypes::LineGeometry )
     return QVariant();
 
-  return QVariant( qgsgeometry_cast< const QgsLineString * >( geom.constGet() )->length3D() );
+  if ( !geom.isMultipart() )
+    return QVariant( qgsgeometry_cast< const QgsLineString * >( geom.constGet() )->length3D() );
+
+  if ( const QgsGeometryCollection *collection = qgsgeometry_cast< const QgsGeometryCollection * >( geom.constGet() ) )
+  {
+    if ( collection->numGeometries() > 0 )
+    {
+      double sumLength3DParts = 0;
+      for ( int i = 0; i < collection->numGeometries(); ++i )
+      {
+        sumLength3DParts += qgsgeometry_cast< const QgsLineString * >( collection->geometryN( i ) )->length3D();
+      }
+      return QVariant( sumLength3DParts );
+    }
+  }
+
+  return QVariant();
 }
 
 static QVariant fcnReplace( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )