Hi @michiedem​ 

Have tried the DonutHoleExtractor transformer?

The Outershell port should give you desired result.

Hello @rahulsharma​ 

I think you must have misunderstood me. My source is a DEM (raster/Geotiff) of an area with ditches. in Arcmap/Qgis you can do a fill sink analyses that will result in a raster with all depressions filled. I want to do something comparable in FME.

I did write a custom tranformer yesterday that looks at all surrounding cells, if they are all higher it lifts the cell to the lowest hight, I then loop back to do the same again. This seems to work, but obvioulsy is incredibly slow.