Fixing thousands of small overlapping polygons?
If your polygons are slivers the eliminate command works well to merge them into either the larger area polygon or the longest edge.
If the polygons are overlaps then there may be an easier way, but I would select out the overlaps to a separate layer, then union them back in, creating the slivers and using the eliminate command.
- Select a small area and convert into two shape files to see if this process is working.
- Create a new field named test (number) in s1 and s2.
- Intersect two shape files S1 and S2.
- Overlapping areas will be identified in a separate file e.g. named Common1 (Hatched Area in figure).
- Calculate the field test as 1 in Common.
- Union S1 and Common
- Select 1 from test field and delete the hatched area.
- Now Merge s2 and common. Erase command can be used to erase the common area.
Have you considered breaking the individual land use classes into separate shapefiles to work with them that way. I first thought of running an intersect but I saw that failed above. If you have seven separate shapefiles though, you may be able to manipulate them more easily.
The main question I have is if there is overlap, do you have a hierarchy for which class wins and should show in the end? For example: if Cropping and Dairy overlap, which do you keep? Once you have this hierarchy settled, intersect 2 classes at a time, starting with the lowest and ending with the highest. If your output is empty on a given intersect, that means they do not intersect.