Spectral Unmixing using mesma function/ Problem with low values

[ALoak21]

Hello There!

I'm currently trying to do some spectral unmixing with Landsat 4-8 Data. For this, i am using the mesma() function, developed by jakob schwalb-willmann. Apart from some vegetational Endmember/spectra, for e. g. floodplain areas and wetlands, i also tried to run the unmixing function with a shade-spectrum for calculating the percentage of shade in each pixel. For this, i added the value 0.000001 for each band of the raster layer (in my Sources, the calculation of the shade-percentage is done with setting the values to 0, but then the results of mesma() are completely trash). Normally, the expected values/percentage of the Endmember spectra in each pixel after the unmixing should be between 0 and 1. But this time, the mesma function calculates values from 0 to 364649.8, which in my opinion can't be right. Has anybody an idea, why? Mesma uses a non-negative least squares solver, maybe this is a reason for the problem?

Part of the code i'm using: Em_pos = st_read("path") # reading the table with the geographic position of the Endmember in the Data s_05_07_19 = stack("path") # raster, from which the Endmember should be extracted EM_L7 = extract(s_05_07_19, Em_pos) # extracting the Endmember from the Raster EM_L7.df = as.data.frame(EM_L7) EM_L7.df [8,] = c(0.000001,0.000001,0.000001,0.000001,0.000001,0.000001,0.000001) # adding the shade-class to the Frame Data = stack ("path") # raster, for which the unmix-function should be applied unmix = mesma(Data,EM_L7.df,method = "NNLS",verbose = T)