I have a raster of an area with various elevated features, situated on an overall slope. I want to normalize the elevations of each feature by subtracting the lowest elevation at each feature. This is unique to each feature in the raster. The end goal is to plot the elevation distribution of each feature.
My current approach (which is very rough): I digitized each feature into a shapefile for the whole area. I used this shapefile to extract by mask, and imported the resulting grid into MATLAB. I took the extents from each polygon and found the minimum point on the perimeter and subtracted this value from all the values within the extent "box". However, some of these features are close to one another so I end up subtracting values twice from the same feature.
I also ran Zonal Statistics to calculate the minimum elevation at each polygon. There has to be some simple tool I'm missing to subtract a unique value from the areas of the raster within each polygon, but I can't find a solution.