Merge Adjacent Polygons by Attribute?

[JessicaGorzo]

Hey all- I have polygons with various forest type classifications, some are "unknown." If an "unknown" type polygon is adjacent to a polygon with any known forest type, I want to merge them and define the new polygon by the known type. Is there an easy way to do this?

Thanks!;)

[JohnSobetzer]

Given that any unknown might abut multiple type polys, it might be something you will want to do manually by selecting the two polys and then merging to the typed poly.  But if an automatic process will do and save you a lot of work, you might select all unknown polys and then run an Eliminate.  You do have some options for the selection method which you can get from the tool help.

[JessicaGorzo]

John, thanks! Eliminate indeed does what I need. I didn't think this would just be a simple "one tool" issue but I'm glad it was! 😮

[MartyRyan]

Jessica, Would you be able to share the settings you used? I am attempting something similar - I'm trying to merge polygons less than .5 acres in area into the adjacent polygon. I think I followed John's suggestion about creating a selection and have selected all the small polygons I want to eliminate. The Eliminate tool has been running for over 20 hours and is at the Processing Tiles step for most of that time - progress bar goes to 100%, then cycles back to 23% or so and repeats this pattern over and over. Does this sound familiar? (I am trying to eliminate 13, 000 polygons out of a dataset that has 334,000 polygons. )