i have one file, with 32000 record ,its polygons for city ,when i want to merge some polygons for get one rooftop polygon from many polygons ,this new polygon remove or it's have unwanted lines between the old polygons , how i can to merge polygons for get aggregate polygon ? i need edit by hand not tools , thanks ;
The remaining lines are there because your topology is not correct (very small gap between two polygon boundaries). Before you use the "merge" in edition, you should run "integrate" to clean your dataset. Once you have done that, you should not have artefacts after merging adjacent polygons.