I have a question about multiple raster layer regression using R or Arcgis. I would like to predict biomass using some Vegetation Index - VI (NDVI, EVI, SAVI, OSAVI...). and generate R² and RMSE maps for my study area.
At first moment, I cut the VI images and stacked them with biomass, because I have for some areas biomass field plot. So, I create a stack with biomass field and VI's. Then I extracted the value (Biomass and VI's for each pixel where I have biomass value) and generated a model to predict biomass (I have used R and
regsubset function to do it). Doing this a got, for example (
Biomass = B0 + B1*NDVI + B2*SAVI) I could apply this model in my VI's images to extrapolate, but I will have only biomass maps.
I think to get R², RMSE maps, I must do a different process, someone could help me?