[GRASS] Fix writing projection for new mapsets

Use the more modern API so that the projection SRID and WKT
are written losslessly to the mapset

Avoids loss of projection information when creating
mapsets

src/plugins/grass/qgsgrassnewmapset.cpp

@@ -399,18 +399,9 @@ void QgsGrassNewMapset::setGrassProjection()
     const QString wkt = crs.toWkt( QgsCoordinateReferenceSystem::WktVariant::WKT_PREFERRED );
     QgsDebugMsgLevel( QStringLiteral( "wkt = %1" ).arg( crs.toWkt( Qgis::CrsWktVariant::Preferred ) ), 3 );
 
-    // Note: GPJ_osr_to_grass() defaults in PROJECTION_XY if projection
-    //       cannot be set
-
     G_TRY
     {
-      // There was a bug in GRASS, it is present in 6.0.x line
-      int ret = GPJ_wkt_to_grass( &mCellHead, &mProjInfo, &mProjUnits, wkt.toUtf8().constData(), 0 );
-      // Note: It seems that GPJ_osr_to_grass()returns always 1,
-      //   -> test if mProjInfo was set
-
-      Q_UNUSED( ret )
-      QgsDebugMsgLevel( QString( "ret = %1" ).arg( ret ), 2 );
+      GPJ_wkt_to_grass( &mCellHead, &mProjInfo, &mProjUnits, wkt.toUtf8().constData(), 0 );
     }
     G_CATCH( QgsGrass::Exception & e )
     {
@@ -422,13 +413,20 @@ void QgsGrassNewMapset::setGrassProjection()
     {
       setError( mProjErrorLabel, tr( "Selected projection is not supported by GRASS!" ) );
     }
+    else
+    {
+      mProjSrid = crs.authid().toUpper();
+      mProjWkt = wkt;
+    }
   }
   else // Nothing selected
   {
     mCellHead.proj = PROJECTION_XY;
     mCellHead.zone = 0;
     mProjInfo = nullptr;
     mProjUnits = nullptr;
+    mProjSrid.clear();
+    mProjWkt.clear();
   }
   button( QWizard::NextButton )->setEnabled( mProjInfo && mProjUnits );
 }
@@ -1106,7 +1104,10 @@ void QgsGrassNewMapset::createMapset()
     QString error;
     G_TRY
     {
-      ret = G_make_location( location.toUtf8().constData(), &mCellHead, mProjInfo, mProjUnits );
+      ret = G_make_location_crs( location.toUtf8().constData(),
+                                 &mCellHead, mProjInfo, mProjUnits,
+                                 mProjSrid.toUtf8().constData(),
+                                 mProjWkt.toUtf8().constData() );
     }
     G_CATCH( QgsGrass::Exception & e )
     {

src/plugins/grass/qgsgrassnewmapset.h

@@ -195,6 +195,8 @@ class QgsGrassNewMapset : public QWizard, private Ui::QgsGrassNewMapsetBase
     struct Cell_head mCellHead;
     struct Key_Value *mProjInfo = nullptr;
     struct Key_Value *mProjUnits = nullptr;
+    QString mProjSrid;
+    QString mProjWkt;
 
     //! Previous page
     int mPreviousPage = -1;