I am using the Hansen forest cover and loss dataset in ArcMap in order to calculate both forest cover and forest loss within specified zones.

I basically am using Modelbuilder to iterate through all my "cover" and "loss" rasters, and using the "Tabulate Area" tool with the polygon shapefile to define my zones.

In order to use the "Tabulate Area" tool I must first convert the shapefile with the specified zones into a raster (because Tabulate Area has some issues with overlapping polygons). However, the output raster loses some zones.

I tried again using "Tabulate Area II" with and without converting my polygon shapefile to a raster and still have less polygons than the original shapefile!

At this point my only option has been to mosaic the rasters together, and split the polygon shapefile by attribute in order to iterate through zones in Modelbuilder, but mosaicing rasters takes ages.

Does anyone have any tips on either speeding up the mosaic process, or Tabulating the area of overlapping polygons?

  • Actually you need to repair the geometry to get rid of overlapping polygons. Overlapping polygons cause problems most of the time so you need to fix them. – ahmadhanb Sep 17 at 18:44
  • But the polygons do actually overlap spatially. How can I correct them without losing their spatial orientation? – seak23 Sep 17 at 19:31
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    Can you add a picture to show us how it looks like? A picture is worth a thousand words. – ahmadhanb Sep 18 at 5:39

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