I am attempting to obtain the rainfall erosivity "R" factor for the RUSLE Soil Loss equation using rainfall PRISM 30 year history data. I have both monthly and annual data that comes into ArcMap as rasters, so in total I have 13 raster images in Arc Map. In the images below, I have placed the 12 monthly rainfall rasters into model builder, to convert the rasters to points, interpolate them using the Spline tool, and Extract by Mask, in order to get them ready for use in the Fournier Index. Above shows the process of getting them through each tool in Arc Map. (seen in second image below). ![enter image description here] Once I have the "Extract" rasters (image 2), I will place them into the Fournier Index formula, which in turn will give me the R factor for the RUSLE. The problem with this, is that when I finish the model builder equation, I am left with the monthly averages all having the same raster value.
So In turn, when I plug them into the R factor Fournier equation, I'm left with irrelevant data. Does anyone know the solution to this? I'm pretty new to stack exchange, so I apologize if I've asked the question incorrectly.