PROJ6: msOGRSpatialRef2ProjectionObj: avoid going through potentially…

… lossy PROJ4 strings

mapogr.cpp

@@ -974,6 +974,26 @@ static int msOGRSpatialRef2ProjectionObj(OGRSpatialReferenceH hSRS,
     return MS_SUCCESS;
   }
 
+#if PROJ_VERSION_MAJOR >= 6
+  // This could be done also in the < 6 case, but would be useless.
+  // Here this helps avoiding going through potentially lossy PROJ4 strings
+  const char* pszAuthName = OSRGetAuthorityName(hSRS, NULL);
+  if( pszAuthName && EQUAL(pszAuthName, "EPSG") )
+  {
+    const char* pszAuthCode = OSRGetAuthorityCode(hSRS, NULL);
+    if( pszAuthCode )
+    {
+        char szInitStr[32];
+        sprintf(szInitStr, "init=epsg:%d", atoi(pszAuthCode));
+
+        if( debug_flag )
+            msDebug( "AUTO = %s\n", szInitStr );
+
+        return msLoadProjectionString(proj, szInitStr) == 0 ? MS_SUCCESS : MS_FAILURE;
+    }
+  }
+#endif
+
   // Export OGR SRS to a PROJ4 string
   char *pszProj = NULL;
 

mapscript/python/tests/cases/map_test.py

@@ -324,8 +324,7 @@ def testESRIWKT(self):
     def testWellKnownGEOGCS(self):
         self.map.setWKTProjection('WGS84')
         proj4 = self.map.getProjection()
-        assert proj4.find('+proj=longlat') != -1, proj4
-        assert proj4.find('+datum=WGS84') != -1, proj4
+        assert ('+proj=longlat' in proj4 and '+datum=WGS84' in proj4) or proj4 == '+init=epsg:4326', proj4
         assert (mapscript.projectionObj(proj4)).getUnits() != mapscript.MS_METERS