I decided that a shortage of time has prevented me from actually posting commentary and process hints like I had anticipated. Therefore, I will instead try to post hints and tips as I come across workarounds and tools in my daily geospatial tasks. Here’s the first one:
Today’s hint is a simple one. Recently I downloaded a topologically awkward data set from BLM. I had hoped to do a simple intersection of ownership with a study area, but the total acreage was too high. As it turns out this data set has a one-to-many relationship of spatial features to database records represented by simply duplicating the spatial features for each database record. For example, a single location with three owners has 3 identical polygons. I think this is a common solution for what I would call “lazy” GIS design. What I needed to do is simply remove the duplicates. After my first-resort Google search, I found some obsolete scripts, commercial tools, and obtuse processes to fix the problem, but nothing really straightforward. I then simply tried to look through the ArcToolbox to see what I could come up with. There are the Find Identical and Delete Identical. Tools that looked promising, but the documentation indicates they are for duplicate values found in tables, not graphics. On a hunch I tried using the Delete Identical tool but indicated the “Shape” column as one to find duplicates. YEA, it worked.
- First make a copy of your Feature Class. This is one of THOSE commands that doesn’t ask for an output, it just does it to your original data set.
ArcToolbox:
- Data Management Tools > General > Delete Identical
- Select your Feature Class
- Choose the “Shape” column – nothing else.
- Run the tool.
Good Luck!
