don't use underscores in names using mapAdd() #155
Description
It looks like passing layerName = "nw_ab" (with corresponding analysisGroupReportingPolygon = "nw_ab") triggered an issue in postprocessing (specifically Large Patches analyses) where the polygon name had been changed to nw.ab, causing subsequent failures of those analyses.
TODO: check for and document this behaviour. also document that layerName and analysisGroupReportingPolygon should match when using mapAdd.