I've posted a similar question before about this issue: Issue with ESRI API - RasterFunction "Arithmetic" , I'm still having the same issue, but now I have a bit more updated code block and an Image of the results that I am getting. If you don't want to read my previous post, I'll give you a short overview. Basically I'm trying to build a web application that does some basic map algebra using the built in client-side functions called "RasterFunctions". I am running into the issue when I try to use the "Arithmetic" function on two "Remap" (reclassified) rasters. Below is an image of the results I'm getting versus the results I should be getting given the same inputs. FYI the colors on the raster don't have any meaning. Attached is an image of the issue I am getting and the code block that I have been working on. Please let me know if you can help in any way.