Dear all, In an r.mapcalc expression, I would like to trace values along a direction map for 1 to n steps (e.g. looking 4 steps ahead along a path or stream or along a given direction (degrees or 45degrees).
I tried using the neighborhood modifier within an eval function in r.mapcalc. Unfortunately, using this command: r.mapcalc --o << EOF eval(elev_200 = elevation[1,1] - 200, elev_5 = 5 * elev_200[1,1], elev_p = pow(elev_5, 2)) gradient_1 = (0.5 * elev_200) + 0.8 * elev_p EOF I get the following error message: syntax error, unexpected '[', expecting ')' However, this command works fine: r.mapcalc --o << EOF eval(elev_200 = elevation[1,1] - 200, elev_5 = 5 * elevation[1,1], elev_p = pow(elev_5, 2)) gradient_1 = (0.5 * elev_200) + 0.8 * elev_p EOF My questions now are: a) is it generally not supported to use the neighbourhood modifier on a temporary map defined in an eval() function in r.mapcalc? b) are there other (efficient) approaches for those of us who do not know C (e.g. pygrass)? I am grateful for any hint. Kind regards, Stefan
_______________________________________________ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
