I am trying to clip a raster in ArcMap 10.6 (derived from 'make nedcdf raster') to the shape of the Ireland polygon and I keep getting back pixels around the edge:

enter image description here

I have tried 'Clip' in 'Data management' (I have ticked 'Use input features for clipping geomotry' AND 'Maintain clipping extent'). I have also tried 'extract by mask' in Spatial analyst. None of them cut the raster with the Ireland Shapefile. I created this netcdf in R.

Could that be an issue?

Also, I'm wondering if it's because the raster doesn't have coverage for the entire shape of Ireland?

  • I think you are misunderstanding what a raster dataset is and what you can expect to see from a clip operation. See here: desktop.arcgis.com/en/arcmap/10.6/manage-data/raster-and-images/… Still - something is not right here. Can you post a picture of the original netCDF before the supposed clip operation? Do the netCDF and the Ireland polygon share the same coordinate reference system? – GBG Mar 12 at 20:30
  • I don't see any black pixels in your image. Your pixels are very large, you won't get an output raster clipped exactly to the polygon. Rasters can only ever be rectangular, any pixel outside your polygon will still exist, but will be assigned a null/nodata value which may be the black pixels of which you speak. – user2856 Mar 13 at 10:29
  • Thank you both for your comments. I misunderstood what was possible with rasters (i.e.you can't cut the pixel to the shape of a polygon) – matlabcat Apr 20 at 14:51

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