[GRASS-dev] [GRASS-user] compare a DCELL and FCELL question

[ming han]

Hi Micha

     Many thanks for your reply.
     Here is the command I am using:

     if(float(cat1_acc_riv) == float(cat1_minacc), str_r, null())

      The str_r is a CELL raster. the result is different when I change it
to:
       if(int(cat1_acc_riv) == int(cat1_minacc), str_r, null())

    Here is output of r.info for first DCELL raster

+----------------------------------------------------------------------------+
 | Map:      cat1_acc_riv at PERMANENT         Date: Sat Jan 23 22:58:42 2021
   |
 | Mapset:   PERMANENT                      Login of Creator: m43han
   |
 | Location: main_working_location
   |
 | DataBase: C:\Users\m43han\Documents\Routing_Prod\Prod000001\grassdb
   |
 | Title:    cat1_acc_riv
  |
 | Timestamp: none
   |
 |----------------------------------------------------------------------------|
 |
   |
 |   Type of Map:  raster               Number of Categories: 19432056
   |
 |   Data Type:    DCELL
   |
 |   Rows:         4239
  |
 |   Columns:      9254
  |
 |   Total Cells:  39227706
  |
 |        Projection: Latitude-Longitude
   |
 |            N:  50:52:39N    S:  40:16:48N   Res: 0:00:09
  |
 |            E:  70:10:39W    W:  93:18:45W   Res: 0:00:09
  |
 |   Range of data:    min = 250752  max = 19432056
  |
 |
   |
 |   Data Description:
   |
 |    generated by r.mapcalc
   |
 |
   |
 |   Comments:
   |
 |    if(isnull(str_r), null(), acc)
   |
 |
   |
 +----------------------------------------------------------------------------+
(Sun Jan 24 04:45:38 2021) Command finished (0 sec)



Here is r.info output for second raster
 +----------------------------------------------------------------------------+
 | Map:      cat1_minacc at PERMANENT          Date: Sat Jan 23 22:58:48 2021
   |
 | Mapset:   PERMANENT                      Login of Creator: m43han
   |
 | Location: main_working_location
   |
 | DataBase: C:\Users\m43han\Documents\Routing_Prod\Prod000001\grassdb
   |
 | Title:    cat1_minacc
   |
 | Timestamp: none
   |
 |----------------------------------------------------------------------------|
 |
   |
 |   Type of Map:  raster               Number of Categories: 0
  |
 |   Data Type:    FCELL
   |
 |   Rows:         4239
  |
 |   Columns:      9254
  |
 |   Total Cells:  39227706
  |
 |        Projection: Latitude-Longitude
   |
 |            N:  50:52:39N    S:  40:16:48N   Res: 0:00:09
  |
 |            E:  70:10:39W    W:  93:18:45W   Res: 0:00:09
  |
 |   Range of data:    min = 250752  max = 1.817303e+007
   |
 |
   |
 |   Data Description:
   |
 |    generated by r.stats.zonal
   |
 |
   |
 |   Comments:
   |
 |    r.stats.zonal --overwrite base="str_r" cover="cat1_acc_riv" method="\
  |
 |    min" output="cat1_minacc"
  |
 |
   |
 +----------------------------------------------------------------------------+
(Sun Jan 24 04:46:50 2021) Command finished (0 sec)

Thanks
Ming


Micha Silver <tsvibar at gmail.com> 于2021年1月24日周日 上午3:29写道：

> Is there some reason that you expect the rasters to be the same? Maybe
> begin by posting the outputs of `r.info` for both rasters, and what
> command you used to compare them?
>
> On Sun, Jan 24, 2021 at 6:13 AM ming han <dustming at gmail.com> wrote:
> >
> > Hi Everyone
> >
> >     I tried to compare if grids in two rasters are the same, one raster
> is FCELL and another raster is DCELL. I got different result  when I int
> both raster first before comparing them; and when I float() both raster
> first before I comparing them
> >
> > Is there any reason for this?
> >
> > Thanks
> > Ming
> > _______________________________________________
> > grass-user mailing list
> > grass-user at lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/grass-user
>
>
>
> --
> Micha Silver
> Ben Gurion Univ
> Sde-Boker Remote Sensing Lab
> cell: +972 (52) 3665918
>
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