On Tue, Oct 1, 2013 at 3:09 PM, Edzer Pebesma <edzer.pebesma at uni-muenster.de> wrote: > What does "merge" in ArcGIS do? Its 18 years since I last used ESRI products. I know what "merge" in Arc/Info v4 used to do - crash the workstations. plus ca change? Barry