I don't have any experience with GIS and mapping (other than drawing polygons in Google Earth). I need to create custom territory boundaries on a map, with county lines and street/highways as boundaries. These territories that I want to create will be next to each other, so I want to prevent empty spaces between them also.
Are there free tools that will allow me to do this? I attempted to do this using Google Earth's polygon tool, but tracing the county lines along with major highways over a large area is a massive task, and the result is not clean (i.e. my traces don't "snap" to the streets perfectly).