I am trying to calculate index based built-up index (IBI) in ArcMap using raster calculator and getting strange values. I downloaded Landsat 8 data. To get the IBI, first I calculated NDVI with NIR and SWIR1 bands as
Than I use the NDBI, SAVI and MNDWI to calculate IBI as ("NDBI" - ("SAVI" + "MNDWI")/2)/("NDBI" + ("SAVI" + "MNDWI")/2)
I followed the methods of this article to get all to IBI https://link.springer.com/article/10.1007%2Fs10708-020-10148-w
I have also tried to calculate it straight from the bands as done in couple of papers I have seen, where the NDVI is used instead of SAVI but the results did not get any better.
Where is the mistake?