qgscoordinatetransform_p.cpp: avoid issues when opening projects usin…

…g PROJ < 7 grid names (fixes #45470) Only use proj_coordoperation_is_instantiable() if PROJ networking is enabled. The reason is that proj_coordoperation_is_instantiable() in PROJ < 9.0 does not work properly when a coordinate operation refers to a PROJ < 7 grid name (gtx/gsb) but the user has installed PROJ >= 7 GeoTIFF grids. Cf OSGeo/PROJ#3025. When networking is not enabled, proj_create() will check that all grids are present, so proj_coordoperation_is_instantiable() is not necessary.
qgis · Jan 23, 2022 · 1cae722 · 1cae722
1 parent 4f48163
commit 1cae722
Showing 1 changed file with 14 additions and 1 deletion.
diff --git a/src/core/proj/qgscoordinatetransform_p.cpp b/src/core/proj/qgscoordinatetransform_p.cpp
@@ -288,7 +288,20 @@ ProjData QgsCoordinateTransformPrivate::threadLocalProjData()
   if ( !mProjCoordinateOperation.isEmpty() )
   {
     transform.reset( proj_create( context, mProjCoordinateOperation.toUtf8().constData() ) );
-    if ( !transform || !proj_coordoperation_is_instantiable( context, transform.get() ) )
+    // Only use proj_coordoperation_is_instantiable() if PROJ networking is enabled.
+    // The reason is that proj_coordoperation_is_instantiable() in PROJ < 9.0
+    // does not work properly when a coordinate operation refers to a PROJ < 7 grid name (gtx/gsb)
+    // but the user has installed PROJ >= 7 GeoTIFF grids.
+    // Cf https://github.com/OSGeo/PROJ/pull/3025.
+    // When networking is not enabled, proj_create() will check that all grids are
+    // present, so proj_coordoperation_is_instantiable() is not necessary.
+    if ( !transform
+#if PROJ_VERSION_MAJOR >= 7
+         || (
+           proj_context_is_network_enabled( context ) &&
+           !proj_coordoperation_is_instantiable( context, transform.get() ) )
+#endif
+       )
     {
       if ( sMissingGridUsedByContextHandler )
       {