I have a raster of an alluvial outflow (sediment running off a hill, see attached image). It is an integer raster and the flow is represented as 1s and non-flow as zeros. I am trying to create an efficient outline of the flow area. It could be a buffer or a single polygon that shows the extent of the 1s.
I have tried converting the raster to polygons and using Eliminate Polygon Parts for a specified Area (eliminate polygons <1km2, for scale the flow is about 10km long). This initially looks correct, but ArcMap is not actually deleting the eliminated polygons (they are still in the Attribute Table) and if you change the style (like outline thickness) suddenly all the inner small polygons reappear (somewhat maddening). There is a similar bug in creating a layer by selection, where performing a style action brings back the unselected items.
So, I'm open to other options.
I am on ArcMap 10.5 and I have a spatial analyst license. Thanks in advance!
Dave