[GIS] Erasing overlapping polygons from same layer using ModelBuilder

arcgis-desktopmodelbuilderoverlapping-features

I currently have a shapefile with 5 catagories of overlapping polygons ranked 0-4, 1 is the most recent polygon, four is the oldest and 0 is undefined.

I am looking to use ModelBuilderr to seperate this file into each of the five catagories and then merge the entire layer diplaying only the highest ranked polygon (no overlapping older/lower ranked polygons drawn) as the file has over a 1000 polygons and the goal is to speed up drawing and use the final layer as asa reference to quickly visually identify the most current file for an area.

New to ModelBuilder.

Best Answer

Firstly run the union tool on the shapefiles. Quoting from the documentation...

Union can run with a single input feature class or layer. In this case, instead of discovering overlap between the polygon features from the different feature classes or layers, it will discover the overlap between features within the single input. The areas where features overlap will be separated into new features with all the attribute information of the input feature. The area of overlap will always generate two identical overlapping features, one for each of the features that participates in that overlap

This will create a set of identical overlapping features. You can calculate the highest rank using the dissolve tool. The dissolve tool needs a unique attribute that is the same for all the polygons within a set.

  1. Add a string column and run field calculator using the following python. This will create a unique reference for the shapes based on area, and centroid.

    str(!shape.area!)+'-'+str(!SHAPE.CENTROID!.split()[0])+"-"+str(!SHAPE.CENTROID!.split()[1])

  2. Run the dissolve tool using the unique reference as the field. Include a maximum statistic column for your rank.
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