I am doing a comparison between two surfaces, the determining how much of that surface has changed within the floodplain I have delineated in this area. The original was flown in 1998 and the newer one was flown in 2012. I was able to use the Raster Math tool to determine exactly where and by how much the surface has changed above or below the original elevation.
I was able to manually break the symbology to show what portion of the surface has gone down 2 feet or more from the original, but here I get stuck. I need a way to extract only that portion of the raster, then convert it to a polygon and quantify area of -2ft. change within the floodplain.
Does anyone have any suggestions? I am stumped here. Any help would be greatly appreciated. Thank you!