When matching render elevation range to layer ranges, only consider

datasets from the same parent group

python/PyQt6/core/auto_generated/mesh/qgsmeshdataset.sip.in

@@ -431,6 +431,13 @@ Constructs a valid metadata object
     QString name() const;
 %Docstring
 Returns name of the dataset group
+%End
+
+    QString parentGroup() const;
+%Docstring
+Returns the name of the dataset's parent group.
+
+.. versionadded:: 3.38
 %End
 
     QString uri() const;

python/core/auto_generated/mesh/qgsmeshdataset.sip.in

@@ -431,6 +431,13 @@ Constructs a valid metadata object
     QString name() const;
 %Docstring
 Returns name of the dataset group
+%End
+
+    QString parentGroup() const;
+%Docstring
+Returns the name of the dataset's parent group.
+
+.. versionadded:: 3.38
 %End
 
     QString uri() const;

src/core/mesh/qgsmeshdataset.cpp

@@ -19,6 +19,8 @@
 #include "qgsmeshdataprovider.h"
 #include "qgsrectangle.h"
 #include "qgis.h"
+#include <QRegularExpression>
+#include <QRegularExpressionMatch>
 
 QgsMeshDatasetIndex::QgsMeshDatasetIndex( int group, int dataset )
   : mGroupIndex( group ), mDatasetIndex( dataset )
@@ -142,6 +144,13 @@ QgsMeshDatasetGroupMetadata::QgsMeshDatasetGroupMetadata( const QString &name,
   , mReferenceTime( referenceTime )
   , mIsTemporal( isTemporal )
 {
+  const thread_local QRegularExpression parentGroupNameRegex( QStringLiteral( "^(.*):.*?$" ) );
+
+  const QRegularExpressionMatch parentGroupMatch = parentGroupNameRegex.match( mName );
+  if ( parentGroupMatch.hasMatch() )
+  {
+    mParentGroupName = parentGroupMatch.captured( 1 );
+  }
 }
 
 QMap<QString, QString> QgsMeshDatasetGroupMetadata::extraOptions() const
@@ -169,7 +178,13 @@ QString QgsMeshDatasetGroupMetadata::name() const
   return mName;
 }
 
-QgsMeshDatasetGroupMetadata::DataType QgsMeshDatasetGroupMetadata::dataType() const
+QString QgsMeshDatasetGroupMetadata::parentGroup() const
+{
+  return mParentGroupName;
+}
+
+QgsMeshDatasetGroupMetadata::DataType
+QgsMeshDatasetGroupMetadata::dataType() const
 {
   return mDataType;
 }

src/core/mesh/qgsmeshdataset.h

@@ -397,6 +397,13 @@ class CORE_EXPORT QgsMeshDatasetGroupMetadata
      */
     QString name() const;
 
+    /**
+     * Returns the name of the dataset's parent group.
+     *
+     * \since QGIS 3.38
+     */
+    QString parentGroup() const;
+
     /**
      * Returns the uri of the source
      *
@@ -457,6 +464,7 @@ class CORE_EXPORT QgsMeshDatasetGroupMetadata
 
   private:
     QString mName;
+    QString mParentGroupName;
     QString mUri;
     bool mIsScalar = false;
     DataType mDataType = DataType::DataOnFaces;

src/core/mesh/qgsmeshlayerrenderer.cpp

@@ -99,28 +99,47 @@ QgsMeshLayerRenderer::QgsMeshLayerRenderer(
 
         case Qgis::MeshElevationMode::FixedRangePerGroup:
         {
-          // find the top-most group which matches the map range
-          int currentMatchingGroup = -1;
-          QgsDoubleRange currentMatchingRange;
+          // find the top-most group which matches the map range and parent group
+          int currentMatchingVectorGroup = -1;
+          int currentMatchingScalarGroup = -1;
+          QgsDoubleRange currentMatchingVectorRange;
+          QgsDoubleRange currentMatchingScalarRange;
+
           const QMap<int, QgsDoubleRange > rangePerGroup = elevProp->fixedRangePerGroup();
+
+          const int activeVectorDatasetGroup = mRendererSettings.activeVectorDatasetGroup();
+          const int activeScalarDatasetGroup = mRendererSettings.activeScalarDatasetGroup();
+
           for ( auto it = rangePerGroup.constBegin(); it != rangePerGroup.constEnd(); ++it )
           {
             if ( it.value().overlaps( context.zRange() ) )
             {
-              if ( currentMatchingRange.isInfinite()
-                   || ( it.value().includeUpper() && it.value().upper() >= currentMatchingRange.upper() )
-                   || ( !currentMatchingRange.includeUpper() && it.value().upper() >= currentMatchingRange.upper() ) )
+              const bool matchesVectorParentGroup = QgsMeshLayerUtils::haveSameParentGroup( layer, QgsMeshDatasetIndex( activeVectorDatasetGroup ), QgsMeshDatasetIndex( it.key() ) );
+              const bool matchesScalarParentGroup = QgsMeshLayerUtils::haveSameParentGroup( layer, QgsMeshDatasetIndex( activeScalarDatasetGroup ), QgsMeshDatasetIndex( it.key() ) );
+
+              if ( matchesVectorParentGroup && (
+                     currentMatchingVectorRange.isInfinite()
+                     || ( it.value().includeUpper() && it.value().upper() >= currentMatchingVectorRange.upper() )
+                     || ( !currentMatchingVectorRange.includeUpper() && it.value().upper() >= currentMatchingVectorRange.upper() ) ) )
               {
-                currentMatchingGroup = it.key();
-                currentMatchingRange = it.value();
+                currentMatchingVectorGroup = it.key();
+                currentMatchingVectorRange = it.value();
+              }
+
+              if ( matchesScalarParentGroup && (
+                     currentMatchingScalarRange.isInfinite()
+                     || ( it.value().includeUpper() && it.value().upper() >= currentMatchingScalarRange.upper() )
+                     || ( !currentMatchingScalarRange.includeUpper() && it.value().upper() >= currentMatchingScalarRange.upper() ) ) )
+              {
+                currentMatchingScalarGroup = it.key();
+                currentMatchingScalarRange = it.value();
               }
             }
           }
-          if ( currentMatchingGroup >= 0 )
-          {
-            mRendererSettings.setActiveScalarDatasetGroup( currentMatchingGroup );
-            mRendererSettings.setActiveVectorDatasetGroup( currentMatchingGroup );
-          }
+          if ( currentMatchingVectorGroup >= 0 )
+            mRendererSettings.setActiveVectorDatasetGroup( currentMatchingVectorGroup );
+          if ( currentMatchingScalarGroup >= 0 )
+            mRendererSettings.setActiveScalarDatasetGroup( currentMatchingScalarGroup );
         }
       }
     }

src/core/mesh/qgsmeshlayerutils.cpp

@@ -18,6 +18,8 @@
 #include <limits>
 #include <QTime>
 #include <QDateTime>
+#include <QRegularExpression>
+#include <QRegularExpressionMatch>
 
 #include "qgsmeshlayerutils.h"
 #include "qgsmeshtimesettings.h"
@@ -702,4 +704,17 @@ QVector<QVector3D> QgsMeshLayerUtils::calculateNormals( const QgsTriangularMesh
   return normals;
 }
 
+bool QgsMeshLayerUtils::haveSameParentGroup( const QgsMeshLayer *layer, const QgsMeshDatasetIndex &index1, const QgsMeshDatasetIndex &index2 )
+{
+  const QgsMeshDatasetGroupMetadata metadata1 = layer->datasetGroupMetadata( index1 );
+  if ( metadata1.parentGroup().isEmpty() )
+    return false;
+
+  const QgsMeshDatasetGroupMetadata metadata2 = layer->datasetGroupMetadata( index2 );
+  if ( metadata2.parentGroup().isEmpty() )
+    return false;
+
+  return metadata1.parentGroup().compare( metadata2.parentGroup(), Qt::CaseInsensitive ) == 0;
+}
+
 ///@endcond

src/core/mesh/qgsmeshlayerutils.h

@@ -369,6 +369,14 @@ class CORE_EXPORT QgsMeshLayerUtils
       const QgsTriangularMesh &triangularMesh,
       const QVector<double> &verticalMagnitude,
       bool isRelative );
+
+    /**
+     * Returns TRUE if the datasets from \a layer at \a index1 and \a index2 share the same parent group.
+     *
+     * \since QGIS 3.38
+     */
+    static bool haveSameParentGroup( const QgsMeshLayer *layer, const QgsMeshDatasetIndex &index1, const QgsMeshDatasetIndex &index2 );
+
 };
 
 ///@endcond