Hi, I want to calculate the NDVI (vegetation index) from a landsat-sat imported into rasterenabled postgis. I thought I could use st_mapalgebra() for this. my raster is stored in one postgis table having one row but 4 bands within this row (rid=1).
how to access the specific bands to make st_mapalgebra calculate some new raster? select st_mapalgebra(rast, '(4-3)/(4+3)') from foo; or select st_mapalgebra(rast, '(st_band(rast, 4)-st_band(rast, 3))/(st_band(rast, 4)+st_band(rast, 3))') from foo; does not work Marco _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
