NDVI is calculated on reflectance values in these bands, not raw DN. Your inputs should already be floating point values, and they should never be less than 0.0 or greater than 1.0.
Ok, my raw data was 8BUI which I went back and changed to 64 bit float to try get past this but still, using the equation above is returning: "NOTICE: Neither raster provided has a NODATA value for the specified band indices. NODATA value set to minimum possible for 64BF ERROR: division by zero CONTEXT: SQL statement "SELECT (($1 - $2) /($1 + $2))::double precision" I went back and re-edited the raw raster image to remove the black areas from where it has been geo-rectified but still can't seem to get to grips with what is going wrong in the calculation. -- View this message in context: http://postgis.17.n6.nabble.com/NDVI-Calculation-from-two-bands-within-one-Raster-tp4656995p4660390.html Sent from the PostGIS - User mailing list archive at Nabble.com. _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
