Question

You have a slope raster and an aspect raster. The slope raster has 3 values: 1 for 0-20%, 2 for 20-40%, and 3 for >40%. The aspect raster has 5 values: 1 for flat area, 2 for north, 3 for east, 4 for south, and 5 for west. Describe/write a procedure you will follow to locate those areas with 0-20% slope and the north aspect.

Answer 1

I would start as I did above (examine data in ArcCatalog). In ArcMap, I would add the two rasters. I woulddo a search for slope (because I don’t remember exactly which section these tools are) and I wouldchoose the slope that mentions raster data. I would then ensure that the input is the slope raster, definethe slope as 20-40% and ensure my output is within my workspace. I would add the data to the layer anddouble check if it was what I wanted. If it was, I would save. I also believe I could select by attribute (inthis case the value 2 under the slope raster). In much the same way I would select the aspect value 4 onthe aspect raster and export the data (in my workspace) and add it to the map. I would then doublecheck that I have what I wanted (i.e.areas with 20-40% slope and the south aspect) and I would goto layout view and add map elements (finishing with a neatline).