Don't permit user set vertical crs for project when crs is geographic 3d

or geocentric

Following https://docs.ogc.org/as/18-005r5/18-005r5.html#34 it is not
a valid combination to create a compound crs from these types

src/app/project/qgsprojectelevationsettingswidget.cpp

@@ -178,11 +178,23 @@ void QgsProjectElevationSettingsWidget::updateVerticalCrsOptions()
                                   ) );
       break;
 
+    case Qgis::CrsType::Geographic3d:
+      mVerticalCrsStackedWidget->setCurrentWidget( mCrsPageDisabled );
+      mCrsDisabledLabel->setText( tr( "Project coordinate reference system is set to a geographic 3D CRS (%1), so the vertical CRS cannot be manually specified." ).arg(
+                                    QgsProject::instance()->crs().userFriendlyIdentifier()
+                                  ) );
+      break;
+
+    case Qgis::CrsType::Geocentric:
+      mVerticalCrsStackedWidget->setCurrentWidget( mCrsPageDisabled );
+      mCrsDisabledLabel->setText( tr( "Project coordinate reference system is set to a geocentric CRS (%1), so the vertical CRS cannot be manually specified." ).arg(
+                                    QgsProject::instance()->crs().userFriendlyIdentifier()
+                                  ) );
+      break;
+
     case Qgis::CrsType::Unknown:
     case Qgis::CrsType::Geodetic:
-    case Qgis::CrsType::Geocentric:
     case Qgis::CrsType::Geographic2d:
-    case Qgis::CrsType::Geographic3d:
     case Qgis::CrsType::Vertical:
     case Qgis::CrsType::Projected:
     case Qgis::CrsType::Temporal:

src/core/project/qgsproject.cpp

@@ -1079,11 +1079,27 @@ bool QgsProject::setVerticalCrs( const QgsCoordinateReferenceSystem &crs, QStrin
         }
         break;
 
+      case Qgis::CrsType::Geographic3d:
+        if ( crs != oldVerticalCrs )
+        {
+          if ( errorMessage )
+            *errorMessage = QObject::tr( "Project CRS is a Geographic 3D CRS, specified Vertical CRS will be ignored" );
+          return false;
+        }
+        break;
+
+      case Qgis::CrsType::Geocentric:
+        if ( crs != oldVerticalCrs )
+        {
+          if ( errorMessage )
+            *errorMessage = QObject::tr( "Project CRS is a Geocentric CRS, specified Vertical CRS will be ignored" );
+          return false;
+        }
+        break;
+
       case Qgis::CrsType::Unknown:
       case Qgis::CrsType::Geodetic:
-      case Qgis::CrsType::Geocentric:
       case Qgis::CrsType::Geographic2d:
-      case Qgis::CrsType::Geographic3d:
       case Qgis::CrsType::Projected:
       case Qgis::CrsType::Temporal:
       case Qgis::CrsType::Engineering:
@@ -1597,6 +1613,8 @@ bool QgsProject::rebuildCrs3D( QString *error )
     switch ( mCrs.type() )
     {
       case Qgis::CrsType::Compound:
+      case Qgis::CrsType::Geographic3d:
+      case Qgis::CrsType::Geocentric:
         mCrs3D = mCrs;
         break;
 
@@ -1608,9 +1626,7 @@ bool QgsProject::rebuildCrs3D( QString *error )
 
       case Qgis::CrsType::Unknown:
       case Qgis::CrsType::Geodetic:
-      case Qgis::CrsType::Geocentric:
       case Qgis::CrsType::Geographic2d:
-      case Qgis::CrsType::Geographic3d:
       case Qgis::CrsType::Projected:
       case Qgis::CrsType::Temporal:
       case Qgis::CrsType::Engineering:

tests/src/python/test_qgsproject.py

@@ -256,13 +256,19 @@ class TestQgsProject(QgisTestCase):
         self.assertEqual(project.verticalCrs().authid(), 'EPSG:5703')
         self.assertEqual(len(spy), 1)
 
-        # invalid combination
+        # invalid combinations
         project.setCrs(QgsCoordinateReferenceSystem('EPSG:4979'))
         ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5711'))
         self.assertFalse(ok)
-        self.assertEqual(err, 'components of the compound CRS do not belong to one of the allowed combinations of http://docs.opengeospatial.org/as/18-005r5/18-005r5.html#34')
+        self.assertEqual(err, 'Project CRS is a Geographic 3D CRS, specified Vertical CRS will be ignored')
         self.assertEqual(project.crs3D().authid(), 'EPSG:4979')
 
+        project.setCrs(QgsCoordinateReferenceSystem('EPSG:4978'))
+        ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5711'))
+        self.assertFalse(ok)
+        self.assertEqual(err, 'Project CRS is a Geocentric CRS, specified Vertical CRS will be ignored')
+        self.assertEqual(project.crs3D().authid(), 'EPSG:4978')
+
     def test_crs_3d(self):
         project = QgsProject()
         self.assertFalse(project.crs3D().isValid())