Thanks a lot Moritz..!!!!!!! I got it and I'll read the mapcalc manual as well.
Thanks again Best regards Kalindu Perera On Fri, 26 Oct 2018 at 13:25, Moritz Lennert <mlenn...@club.worldonline.be> wrote: > > > Am 26. Oktober 2018 09:08:11 MESZ schrieb Kalindu Perera < > kkc199...@gmail.com>: > >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 > ><mlenn...@club.worldonline.be> > >wrote: > > > >> > >> > >> Am 26. Oktober 2018 06:42:44 MESZ schrieb Kalindu Perera < > >> kkc199...@gmail.com>: > >> >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 > >> >
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