I have a DEM in a Mosaic Dataset covering a large area (300 x 200 km). I want to create a classified slope raster showing slopes of say 0 - 10 degrees, 10 - 20 degrees, and then 20 - 90 degrees. Because the dataset is so large I want to avoid having to create a separate slope raster dataset, but instead use the Image Analysis so I can visually see where the slope classes are.
In the Image Analysis window I can create a Slope Function for my dem and display it using the Stretched color ramp in the Symbology tab of the Layer Properties. I want to use the Classified renderer, but Arc requires the data to have a histogram. When I say Yes, it chugs away computing the statistics and histogram. For really large datasets it can take a very long time. I'm wondering where the histogram and statistics are stored for a Image Analysis layer because it this Compute Histogram dialog keeps re-appearing.
I thought there could be a way to create this with a Function chain. There are functions called: Classify, Colormap, Remap that sound promising, but I haven't gotten any of them to work
The Classify function wants a .ECD or .ACT file as input. How do I create a ECD or ACT file or is there a better way to accomplish this?