I'm trying to dissolve an hydrologic system because I have to many small portions for what I want to do but I can't figure how to make dissolve work ... the shapefile I'm using is a merge of different shapefiles (some I edited manually)
Here is how I set it up :
but when I execute it I get this message :
Do you know how I can fix this or if there is another way to reduce the number of entities in my attribute table? I have tried multipart to single part but it didn't reduce the number of items in my attribute table. Even having just one big entity could work ...