Am 26. Oktober 2018 09:08:11 MESZ schrieb Kalindu Perera <[email protected]>: >Thanks a lot Moritz....!!!!!!!! > >Can you just send me one example command?..I'm not sure I understood it >in >the way that you explained
Please do read the r.mapcalc manual, but here's an example: r.mapcalc "category_range = if(spread_time_observed >= 1 && spread_time_observed <= 90 , 1, null())" If there are no values below 1 in spread_time_observed, then this can be simplified to r.mapcalc "category_range = if(spread_time_observed <= 90 , 1, null())" The result of each command is a map with pixel values of 1 where the condition is met and null where not. Moritz > >Thanks again for the quick reply >Best regards >Kalindu Perera > >On Fri, 26 Oct 2018 at 11:46, Moritz Lennert ><[email protected]> >wrote: > >> >> >> Am 26. Oktober 2018 06:42:44 MESZ schrieb Kalindu Perera < >> [email protected]>: >> >Dear all, >> > >> >I'm doing wildfire simulations in the Grass. I need to calculate the >> >area >> >of only the wildfire spread from the simulation. For that, I need to >> >take >> >only the wildfire spread as a separate layer. But the drawback is >the >> >values of the cells in the spread is different from point to point. >But >> >it >> >has a range. As an example, the values of cells inside the spread >are >> >ranging from 1-90. The other cells in the map show values more than >> >that. >> >Can I write a mapcalc command for a range like this to output these >> >cells >> >as one layer? >> > >> >@Nikos has sent me this mapcalc command and from that, we can take >only >> >cells with one value as a layer. >> > >> >r.mapcalc "category_3 = if(spread_time_observed == 3, 3, null())" >> > >> >instead of that one value(3) in this can we input a range as >> >above(1-90) >> >and get all those cells with different values as one layer? >> >> You can use >/< and the && (logical AND) to select all pixels within >a >> range in r.mapcalc. >> >> But you could also use r.reclass or r.recode. >> >> Moritz >> _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user
