topic Re: Merge polygons in watershed in ArcGIS Pro Questions

Merge polygons in watershed

AlexiaReyes — Mon, 28 Jun 2021 21:39:38 GMT

I made a watershed using spatial analysis/hydrology tools. Now, I need to merge the polygons that make up the watershed to make one large polygon. When I try to select the polygons I want to merge, the merge feature under the editor tab is grayed out. It does not allow me to use the data management/ merge tool either. Not sure how to work around this

Re: Merge polygons in watershed

JayantaPoddar — Mon, 28 Jun 2021 21:52:16 GMT

If you have used Watershed (Spatial Analyst) tool, its output is a Raster. Please ensure you use a Raster to Polygon (Conversion) tool to convert it to polygon feature class first.

Then you may use Merge under Edit tab, or Dissolve (Data Management) Geoprocessing tool.

Re: Merge polygons in watershed

DanPatterson — Mon, 28 Jun 2021 22:18:56 GMT

if your watersheds numbered from 0 onward, you can simply use

raster >= 0

where raster is your raster's name

or a combination of IsNull and Con

How to change NoData cells to a value—ArcGIS Pro | Documentation

if you just use IsNull, you will get a raster where 1 represents null values and 0 represents all your combined watersheds. you can then use Con to convert 0 to a value, or simply query the previous raster for values == 0