>In general, it's preferable to do as much as possible in each >r.mapcalc command. E.g. rather than: > > r.mapcalc "$GIS_OPT_OUTPUT.r = r#$GIS_OPT_FIRST * .$GIS_OPT_PERCENT + > (1.0 - .$GIS_OPT_PERCENT) * r#$GIS_OPT_SECOND" > r.mapcalc "$GIS_OPT_OUTPUT.g = g#$GIS_OPT_FIRST * .$GIS_OPT_PERCENT + > (1.0 - .$GIS_OPT_PERCENT) * g#$GIS_OPT_SECOND" > r.mapcalc "$GIS_OPT_OUTPUT.b = b#$GIS_OPT_FIRST * .$GIS_OPT_PERCENT + > (1.0 - .$GIS_OPT_PERCENT) * b#$GIS_OPT_SECOND" > >use: > > r.mapcalc <<EOF > $GIS_OPT_OUTPUT.r = r#$GIS_OPT_FIRST * .$GIS_OPT_PERCENT + (1.0 - > .$GIS_OPT_PERCENT) * r#$GIS_OPT_SECOND > $GIS_OPT_OUTPUT.g = g#$GIS_OPT_FIRST * .$GIS_OPT_PERCENT + (1.0 - > .$GIS_OPT_PERCENT) * g#$GIS_OPT_SECOND > $GIS_OPT_OUTPUT.b = b#$GIS_OPT_FIRST * .$GIS_OPT_PERCENT + (1.0 - > .$GIS_OPT_PERCENT) * b#$GIS_OPT_SECOND > EOF > >as the latter will read each input map only once.
This is really good to know, thanks! I've added this hint to r.mapcalc.html in trunk (r36207) and devbr6 (36208). ~ Eric. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
