Re: [GRASS-user] Change value of cells in raster map [UPDATE]

On Fri, 9 Jun 2017, Rich Shepard wrote: For one of the two maps created from the overall area this worked fine. For the other map there is no table where I can change the centroid's value. The othe map displays an 'Update attributes' dialog box with the layer and category tab, but the area

Re: [GRASS-user] Change value of cells in raster map

On Fri, 9 Jun 2017, Mark Seibel wrote: Start editing the vector, then click "update/display attributes" button, then click the appropriate centroid and change the value in the vector table. Mark, For one of the two maps created from the overall area this worked fine. For the other map

Re: [GRASS-user] Change value of cells in raster map

On Fri, 9 Jun 2017, Mark Seibel wrote: Start editing the vector, then click "update/display attributes" button, then click the appropriate centroid and change the value in the vector table. Mark, Thank you. It did not occur to me to change the centroid value. I was looking to add a column

Re: [GRASS-user] Change value of cells in raster map

Rich Shepard wrote > On Thu, 8 Jun 2017, Helmut Kudrnovsky wrote: > >> raster A: >> raster B: raster eg with values 1 and 2 >> >> in R.mapcalc : >> >> if(B==1, A, A/B) >> >> which means in the resulting map: if the cell value in B is equal to 1, >> then >> take the raster cell value of raster A,

Re: [GRASS-user] Change value of cells in raster map

Hi. I'm trying various v.db.* modules to change values in the two vector maps, > then I can recreate the vector maps from these and each will have the > desired value. So far no success, but I'll keep trying. > Start editing the vector, then click "update/display attributes" button, then click

Re: [GRASS-user] Change value of cells in raster map

On Thu, 8 Jun 2017, Helmut Kudrnovsky wrote: raster A: raster B: raster eg with values 1 and 2 in R.mapcalc : if(B==1, A, A/B) which means in the resulting map: if the cell value in B is equal to 1, then take the raster cell value of raster A, otherwise divide the raster cell value of A by

Re: [GRASS-user] Change value of cells in raster map

Rich Shepard wrote > On Thu, 8 Jun 2017, Rich Shepard wrote: > >> r.mapcalc 'output1 = if (mapname@mapset,value = 0.0)' > >Tried it this evening: r.mapcalc does not like this syntax. > >I can create a map with values specified, but they are the size of the > mask. How can I specify a

Re: [GRASS-user] Change value of cells in raster map

On Thu, 8 Jun 2017, Rich Shepard wrote: r.mapcalc 'output1 = if (mapname@mapset,value = 0.0)' Tried it this evening: r.mapcalc does not like this syntax. I can create a map with values specified, but they are the size of the mask. How can I specify a specific map name to r.mapcalc?

Re: [GRASS-user] Change value of cells in raster map

On Thu, 8 Jun 2017, Laurent C. wrote: When I want to modify a raster, I usually draw a vector and use v.to.rast, then r.mapcalc if necessary. Laurent, That's what I've done. Since I did not enter category values for the vector maps I need to use r.mapcalc on the raster maps. Rich

Re: [GRASS-user] Change value of cells in raster map

Hi Rich, When I want to modify a raster, I usually draw a vector and use v.to.rast, then r.mapcalc if necessary. Regards, Laurent 2017-06-08 18:57 GMT-05:00 Rich Shepard : > On Thu, 8 Jun 2017, Mark Seibel wrote: > >> Maybe if-then statements with mapcalc are

Re: [GRASS-user] Change value of cells in raster map

On Thu, 8 Jun 2017, Mark Seibel wrote: Maybe if-then statements with mapcalc are applicable to the situation. outputRaster=if(EXPRESSION,true,false) Mark, I'll try writing an expression that tests for a map name. I can use any output map name because if it contains the appropriate cell

Re: [GRASS-user] Change value of cells in raster map

Hi. >What I fail to see is the appropriate module to modify an existing map > by > changing the value in each cell. Please point me in the right direction. > Maybe if-then statements with mapcalc are applicable to the situation. outputRaster=if(EXPRESSION,true,false) Mark

[GRASS-user] Change value of cells in raster map

I have two raster maps both of which have the value of all cells as 2, with the label 'Category 2.' I want to change the value of all cells in each map, one map to 0.0 the other map to 12.5. r.category allows me to change categories but not values and r.mapcalc allows me to create new maps with