SpatialReference spatialRef = poLayer.GetSpatialRef();
if (alreadyExistingSpatialRefValid)
{
if ((spatialRef != null && alreadyExistingSpatialRef != null &&
spatialRef.IsSame(alreadyExistingSpatialRef) == 0) ||
((spatialRef != null) != (alreadyExistingSpatialRef != null)))
{
System.err.print("Warning : layer "+iLayer+" of "+args[nFirstSourceDataset]+" is not using the same projection system as "
+ "other files in the tileindex. This may cause problems when "
+ "using it in MapServer for example."+((skip_different_projection) ? " Skipping it" : "")+"\n");