topic Re: Raster in ArcGIS Spatial Analyst Questions

Raster

AugustEagles — Fri, 22 Jan 2016 16:01:04 GMT

hello when I use the raster cauculadora I generate an image like the picture below, but I would like to eliminate the small dots in black and keep only the big ones.
I slice is possible or sort the raster image such that I consider starting from a certain minimum amount of pixel?

thank you

Re: Raster

XanderBakker — Fri, 22 Jan 2016 17:22:36 GMT

Maybe by changing something in you calculation you can avoid or reduce the small areas. If not then there are several options:

You could use Focal Statistics—Help | ArcGIS for Desktop with a MAYORITY statistics type.

You could use Generalizing zones with Nibble, Shrink, and Expand—Help | ArcGIS for Desktop

Sometimes converting to polygons, selecting in the polygon featureclass on area and convert back to raster could do the trick, but this is not recommended when you have many small areas

Re: Raster

DanPatterson_Retired — Fri, 22 Jan 2016 18:15:13 GMT

Another tip, that works sometimes is to use the Shrink/Expand without the Nibble step...Shrink tool... say by 1 cell or 2 cells, then use the Expand Tool immediately after on the output of Shrink. It tends to get rid of fiddly bits as well

Re: Raster

DarrenWiens2 — Fri, 22 Jan 2016 19:10:26 GMT

You may be interested in Region Group/Set Null/Nibble, as outlined here: Generalizing classified output by removing small isolated regions—ArcGIS Help | ArcGIS for Desktop