I have a university assignment that requires me to find an optimum location for a land fill site. There are various parameters I need to map. I have managed to map all the ones within a distance of something (using buffering and overlay techniques as in the image), but I have no clue how to define an area outside of a point. I need to define areas 20 miles outside of any major urban area, 20 miles from a major water feature and 10 miles from any national parks. I have all the base information (urban area, water features, national parks) in layers. I have a full licence with all additional add on's at my disposal - I just don;t know which to use or how]1
If I understand you right, you want the opposite of a buffer. Then first, you need a polygon of your area of interest (AOI), say the border of a state or something like that. Second you calculate your distance buffers which you could clip from the previous AOI polygon. That should give the "outside" of the buffers.