Can I use CatchmentSIM with lat/long coordinates?
Yes, CatchmentSIM will project lat/long coordinates on the fly into which projection you choose. You can also use lat/long as the project coordinate system for large scale projects. However, this will disable the length and area calculations (since your raster grid will not have a constant cell size). To overcome this you can export your subsequent subcatchment boundaries after processing and analyse them in other GIS software.