I have created a .shp file of slopes over a range land environment. The goal is to identify any slope over 15% and remove it form the file to calculate graze-able acres. The attached file show a zoomed in area where white no data area encircles flat land(basically a butt or plateau). Obviously grazing animals can not get to the top of the butt to graze but its flat so it shows up as graze-able. I need to find a way to identify and remove all these areas.
A possibility that I know won't work for all your cases might be to query your classes grid for values >= 1 giving you a binary grid you could then look at the zonal geometry tool (thickness) and query for areas less than some specified thickness... alternately you could query the binary grid for zones with less than a certain area. the resultant could be used as a mask to produce a new classes grid.
Sounds like an accessibility analysis. If you know where the cattle is initially you could do a cost distance analysis in raster format (Spatial Analyst required), assigning inaccessible to those areas with high slopes. This way you will end up with a raster showing those part accessible for grazing.
If you're willing to share (part of) the data, I'm sure things will become clearer and that will allow us to come up with a solution. Please also provide info on the versión of ArcGIS and if you hace access to the Spatial Analyst extension.
I think Xanders' idea has potential. Use a line or polygon feature class showing where the cattle could be initially as part of the Cost Distance Analysis.
For example, assuming the islands issue is only buttes/mesas/high elevation areas, you could make the Cattle Starting Locations polygon feature class by just selecting low elevations, then doing the Cost Analysis as Xander suggests. Obviously this will be dependent on your data.
Daniel, That is what I originally did but you will have a Butt that has a 15%+ slope all the way around, and on the top it will be flat. Some of these Butt's can bee 10-20 acres on top. Cattle will never graze them so they need to be removed from the calculation. I am trying to run a tool that will identify and remove any area that is completely surrounded by the 15% or greater slope.
