postgres: convert 4d geometries to 2d (fixes #9748)

src/providers/postgres/qgspostgresconn.cpp

@@ -338,7 +338,7 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
 
   for ( int i = 0; i < ( hasTopology() ? 3 : 2 ); i++ )
   {
-    QString sql, tableName, schemaName, columnName, typeName, sridName, gtableName;
+    QString sql, tableName, schemaName, columnName, typeName, sridName, gtableName, dimName;
     QgsPostgresGeometryColumnType columnType = sctGeometry;
 
     if ( i == 0 )
@@ -348,6 +348,7 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
       columnName = "l.f_geometry_column";
       typeName   = "upper(l.type)";
       sridName   = "l.srid";
+      dimName    = "l.coord_dimension";
       gtableName = "geometry_columns";
       columnType = sctGeometry;
     }
@@ -358,6 +359,7 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
       columnName = "l.f_geography_column";
       typeName   = "upper(l.type)";
       sridName   = "l.srid";
+      dimName    = "2";
       gtableName = "geography_columns";
       columnType = sctGeography;
     }
@@ -373,21 +375,22 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
                    "WHEN l.feature_type = 4 THEN 'GEOMETRYCOLLECTION' "
                    "END AS type";
       sridName   = "(SELECT srid FROM topology.topology t WHERE l.topology_id=t.id)";
+      dimName    = "2";
       gtableName = "topology.layer";
       columnType = sctTopoGeometry;
     }
 
     // The following query returns only tables that exist and the user has SELECT privilege on.
     // Can't use regclass here because table must exist, else error occurs.
-    sql = QString( "SELECT %1,%2,%3,%4,%5,c.relkind"
-                   " FROM %6 l,pg_class c,pg_namespace n"
+    sql = QString( "SELECT %1,%2,%3,%4,%5,%6,c.relkind"
+                   " FROM %7 l,pg_class c,pg_namespace n"
                    " WHERE c.relname=%1"
                    " AND %2=n.nspname"
                    " AND n.oid=c.relnamespace"
                    " AND has_schema_privilege(n.nspname,'usage')"
                    " AND has_table_privilege('\"'||n.nspname||'\".\"'||c.relname||'\"','select')" // user has select privilege
                  )
-          .arg( tableName ).arg( schemaName ).arg( columnName ).arg( typeName ).arg( sridName ).arg( gtableName );
+          .arg( tableName ).arg( schemaName ).arg( columnName ).arg( typeName ).arg( sridName ).arg( dimName ).arg( gtableName );
 
     if ( searchPublicOnly )
       sql += " AND n.nspname='public'";
@@ -409,7 +412,8 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
       QString column = result.PQgetvalue( idx, 2 );
       QString type = result.PQgetvalue( idx, 3 );
       QString ssrid = result.PQgetvalue( idx, 4 );
-      QString relkind = result.PQgetvalue( idx, 5 );
+      int dim = result.PQgetvalue( idx, 5 ).toInt();
+      QString relkind = result.PQgetvalue( idx, 6 );
       bool isView = relkind == "v" || relkind == "m";
 
       int srid = ssrid.isEmpty() ? INT_MIN : ssrid.toInt();
@@ -419,12 +423,13 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
         srid = INT_MIN;
       }
 
-      QgsDebugMsg( QString( "%1 : %2.%3.%4: %5 %6 %7" )
+      QgsDebugMsg( QString( "%1 : %2.%3.%4: %5 %6 %7 %8" )
                    .arg( gtableName )
                    .arg( schemaName ).arg( tableName ).arg( column )
                    .arg( type )
                    .arg( srid )
-                   .arg( relkind ) );
+                   .arg( relkind )
+                   .arg( dim ) );
 
       layerProperty.schemaName = schemaName;
       layerProperty.tableName = tableName;
@@ -433,6 +438,7 @@ bool QgsPostgresConn::getTableInfo( bool searchGeometryColumnsOnly, bool searchP
       layerProperty.types = QList<QGis::WkbType>() << ( QgsPostgresConn::wkbTypeFromPostgis( type ) );
       layerProperty.srids = QList<int>() << srid;
       layerProperty.sql = "";
+      layerProperty.force2d = dim == 4;
       addColumnInfo( layerProperty, schemaName, tableName, isView );
 
       if ( isView && layerProperty.pkCols.empty() )

src/providers/postgres/qgspostgresconn.h

@@ -64,6 +64,7 @@ struct QgsPostgresLayerProperty
   QList<int>                    srids;
   unsigned int                  nSpCols;
   QString                       sql;
+  bool                          force2d;
 
 
   // TODO: rename this !
@@ -113,15 +114,16 @@ struct QgsPostgresLayerProperty
       sridString += QString::number( srid );
     }
 
-    return QString( "%1.%2.%3 type=%4 srid=%5 pkCols=%6 sql=%7 nSpCols=%8" )
+    return QString( "%1.%2.%3 type=%4 srid=%5 pkCols=%6 sql=%7 nSpCols=%8 force2d=%9" )
            .arg( schemaName )
            .arg( tableName )
            .arg( geometryColName )
            .arg( typeString )
            .arg( sridString )
            .arg( pkCols.join( "|" ) )
            .arg( sql )
-           .arg( nSpCols );
+           .arg( nSpCols )
+           .arg( force2d ? "yes" : "no" );
   }
 #endif
 };

src/providers/postgres/qgspostgresfeatureiterator.cpp

@@ -156,7 +156,9 @@ bool QgsPostgresFeatureIterator::fetchFeature( QgsFeature& feature )
 bool QgsPostgresFeatureIterator::prepareSimplification( const QgsSimplifyMethod& simplifyMethod )
 {
   // setup simplification of geometries to fetch
-  if ( !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) && simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && !simplifyMethod.forceLocalOptimization() )
+  if ( !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) &&
+       simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification &&
+       !simplifyMethod.forceLocalOptimization() )
   {
     QgsSimplifyMethod::MethodType methodType = simplifyMethod.methodType();
 
@@ -279,43 +281,51 @@ bool QgsPostgresFeatureIterator::declareCursor( const QString& whereClause )
 {
   mFetchGeometry = !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) && !mSource->mGeometryColumn.isNull();
 
+#if 0
   // TODO: check that all field indexes exist
-  //if ( !hasAllFields )
-  //{
-  //  rewind();
-  //  return false;
-  //}
+  if ( !hasAllFields )
+  {
+    rewind();
+    return false;
+  }
+#endif
 
+  QString query( "SELECT " ), delim( "" );
 
-  const QgsSimplifyMethod& simplifyMethod = mRequest.simplifyMethod();
+  if ( mFetchGeometry )
+  {
+    QString geom = QgsPostgresConn::quotedIdentifier( mSource->mGeometryColumn );
 
-  QString query = "SELECT ", delim = "";
+    if ( mSource->mSpatialColType == sctGeography )
+      geom += "::geometry";
 
-  bool isPointLayer = QGis::flatType( QGis::singleType( mSource->mRequestedGeomType != QGis::WKBUnknown ? mSource->mRequestedGeomType : mSource->mDetectedGeomType ) ) == QGis::WKBPoint;
-  if ( mFetchGeometry && !simplifyMethod.forceLocalOptimization() && simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && !isPointLayer )
-  {
-    QString simplifyFunctionName = simplifyMethod.methodType() == QgsSimplifyMethod::OptimizeForRendering
-                                   ? ( mConn->majorVersion() < 2 ? "snaptogrid" : "st_snaptogrid" )
-                                       : ( mConn->majorVersion() < 2 ? "simplifypreservetopology" : "st_simplifypreservetopology" );
-
-    double tolerance = simplifyMethod.tolerance() * 0.8; //-> Default factor for the maximum displacement distance for simplification, similar as GeoServer does
-
-    query += QString( "%1(%5(%2%3,%6),'%4')" )
-             .arg( mConn->majorVersion() < 2 ? "asbinary" : "st_asbinary" )
-             .arg( QgsPostgresConn::quotedIdentifier( mSource->mGeometryColumn ) )
-             .arg( mSource->mSpatialColType == sctGeography ? "::geometry" : "" )
-             .arg( QgsPostgresProvider::endianString() )
-             .arg( simplifyFunctionName )
-             .arg( tolerance );
-    delim = ",";
-  }
-  else if ( mFetchGeometry )
-  {
-    query += QString( "%1(%2%3,'%4')" )
-             .arg( mConn->majorVersion() < 2 ? "asbinary" : "st_asbinary" )
-             .arg( QgsPostgresConn::quotedIdentifier( mSource->mGeometryColumn ) )
-             .arg( mSource->mSpatialColType == sctGeography ? "::geometry" : "" )
-             .arg( QgsPostgresProvider::endianString() );
+    if ( mSource->mForce2d )
+    {
+      geom = QString( "%1(%2)" )
+             .arg( mConn->majorVersion() < 2 ? "force2d" : "st_force2d" )
+             .arg( geom );
+    }
+
+    if ( !simplifyMethod.forceLocalOptimization() &&
+         mRequest.simplifyMethod().methodType() != QgsSimplifyMethod::NoSimplification &&
+         QGis::flatType( QGis::singleType( mSource->mRequestedGeomType != QGis::WKBUnknown
+                                           ? mSource->mRequestedGeomType
+                                           : mSource->mDetectedGeomType ) ) != QGis::WKBPoint )
+    {
+      geom = QString( "%1(%2,%3)" )
+             .arg( mRequest.simplifyMethod().methodType().methodType() == QgsSimplifyMethod::OptimizeForRendering
+                   ? ( mConn->majorVersion() < 2 ? "snaptogrid" : "st_snaptogrid" )
+                       : ( mConn->majorVersion() < 2 ? "simplifypreservetopology" : "st_simplifypreservetopology" ) )
+                 .arg( geom )
+                 .arg( simplifyMethod.tolerance() * 0.8 ); //-> Default factor for the maximum displacement distance for simplification, similar as GeoServer does
+    }
+
+    geom = QString( "%1(%2,'%3')" )
+           .arg( mConn->majorVersion() < 2 ? "asbinary" : "st_asbinary" )
+           .arg( geom )
+           .arg( QgsPostgresProvider::endianString() );
+
+    query += delim + geom;
     delim = ",";
   }
 
@@ -539,6 +549,7 @@ QgsPostgresFeatureSource::QgsPostgresFeatureSource( const QgsPostgresProvider* p
     , mSpatialColType( p->mSpatialColType )
     , mRequestedSrid( p->mRequestedSrid )
     , mDetectedSrid( p->mDetectedSrid )
+    , mForce2d( p->mForce2d )
     , mRequestedGeomType( p->mRequestedGeomType )
     , mDetectedGeomType( p->mDetectedGeomType )
     , mPrimaryKeyType( p->mPrimaryKeyType )

src/providers/postgres/qgspostgresfeatureiterator.h

@@ -42,6 +42,7 @@ class QgsPostgresFeatureSource : public QgsAbstractFeatureSource
     QgsPostgresGeometryColumnType mSpatialColType;
     QString mRequestedSrid;
     QString mDetectedSrid;
+    bool mForce2d;
     QGis::WkbType mRequestedGeomType; //! geometry type requested in the uri
     QGis::WkbType mDetectedGeomType;  //! geometry type detected in the database
     QgsPostgresPrimaryKeyType mPrimaryKeyType;

src/providers/postgres/qgspostgresprovider.cpp

@@ -46,6 +46,7 @@ QgsPostgresProvider::QgsPostgresProvider( QString const & uri )
     , mPrimaryKeyType( pktUnknown )
     , mSpatialColType( sctNone )
     , mDetectedGeomType( QGis::WKBUnknown )
+    , mForce2d( false )
     , mRequestedGeomType( QGis::WKBUnknown )
     , mShared( new QgsPostgresSharedData )
     , mUseEstimatedMetadata( false )
@@ -2558,12 +2559,12 @@ bool QgsPostgresProvider::getGeometryDetails()
     }
   }
 
-  QString detectedType = mRequestedGeomType == QGis::WKBUnknown ? "" : QgsPostgresConn::postgisWkbTypeName( mRequestedGeomType );
+  QString detectedType;
   QString detectedSrid = mRequestedSrid;
-  if ( !schemaName.isEmpty() && ( detectedType.isEmpty() || detectedSrid.isEmpty() ) )
+  if ( !schemaName.isEmpty() )
   {
     // check geometry columns
-    sql = QString( "SELECT upper(type),srid FROM geometry_columns WHERE f_table_name=%1 AND f_geometry_column=%2 AND f_table_schema=%3" )
+    sql = QString( "SELECT upper(type),srid,coord_dimension FROM geometry_columns WHERE f_table_name=%1 AND f_geometry_column=%2 AND f_table_schema=%3" )
           .arg( quotedValue( tableName ) )
           .arg( quotedValue( geomCol ) )
           .arg( quotedValue( schemaName ) );
@@ -2576,6 +2577,8 @@ bool QgsPostgresProvider::getGeometryDetails()
     {
       detectedType = result.PQgetvalue( 0, 0 );
       detectedSrid = result.PQgetvalue( 0, 1 );
+      if ( result.PQgetvalue( 0, 2 ).toInt() == 4 )
+        mForce2d = true;
       mSpatialColType = sctGeometry;
     }
     else
@@ -2667,6 +2670,10 @@ bool QgsPostgresProvider::getGeometryDetails()
       }
     }
   }
+  else
+  {
+    detectedType = mRequestedGeomType == QGis::WKBUnknown ? "" : QgsPostgresConn::postgisWkbTypeName( mRequestedGeomType );
+  }
 
   mDetectedGeomType = QgsPostgresConn::wkbTypeFromPostgis( detectedType );
   mDetectedSrid     = detectedSrid;
@@ -2729,6 +2736,7 @@ bool QgsPostgresProvider::getGeometryDetails()
           // only what we requested is available
           mDetectedGeomType = layerProperty.types[ 0 ];
           mDetectedSrid     = QString::number( layerProperty.srids[ 0 ] );
+          mForce2d          = layerProperty.force2d;
         }
       }
       else
@@ -2743,6 +2751,7 @@ bool QgsPostgresProvider::getGeometryDetails()
   QgsDebugMsg( QString( "Requested SRID is %1" ).arg( mRequestedSrid ) );
   QgsDebugMsg( QString( "Detected type is %1" ).arg( mDetectedGeomType ) );
   QgsDebugMsg( QString( "Requested type is %1" ).arg( mRequestedGeomType ) );
+  QgsDebugMsg( QString( "Force to 2D %1" ).arg( mForce2d ? "Yes" : "No" ) );
 
   mValid = ( mDetectedGeomType != QGis::WKBUnknown || mRequestedGeomType != QGis::WKBUnknown )
            && ( !mDetectedSrid.isEmpty() || !mRequestedSrid.isEmpty() );

src/providers/postgres/qgspostgresprovider.h

@@ -397,6 +397,7 @@ class QgsPostgresProvider : public QgsVectorDataProvider
     QgsRectangle mLayerExtent;        //! Rectangle that contains the extent (bounding box) of the layer
 
     QGis::WkbType mDetectedGeomType;  //! geometry type detected in the database
+    bool mForce2d;                    //! geometry type needs to be forced to 2d (eg. ZM)
     QGis::WkbType mRequestedGeomType; //! geometry type requested in the uri
     QString mDetectedSrid;            //! Spatial reference detected in the database
     QString mRequestedSrid;           //! Spatial reference requested in the uri