[GRASS-user] Re: Help - Output difference between ARCGIS enviroment settings and GRASS g.region function

[Alejandro Coca Castro]

Hi Mark, i followed your instructions, so i put in command-line

g.region rast=MASK at default nsres=0:00:07.5 ewres=0:00:07.5

Now, I get the same number of columns and rows. However, the cell size
isn't the same that ArcMAP output file...so i think it can be the reason of
non-similar extend and origin....

Below i show you the output gdalinfo,

Driver: AAIGrid/Arc/Info ASCII Grid
Files: D:\gras_data\temp\test5.asc
Size is 5245, 4800
Coordinate System is `'
Origin = (-60.924999999999997,-0.001600000000000)
Pixel Size = (0.002083000000000,-0.002083000000000)
Corner Coordinates:
Upper Left  ( -60.9250000,  -0.0016000)
Lower Left  ( -60.9250000, -10.0000000)
Upper Right ( -49.9996650,  -0.0016000)
Lower Right ( -49.9996650, -10.0000000)
Center      ( -55.4623325,  -5.0008000)
Band 1 Block=5245x1 Type=Int32, ColorInterp=Undefined
  NoData Value=-9999

Do you have others ideas?
------

Jacquie, thanks for your comments, i hope the next SPs versions fix these
kind of bugs.

regards,

2012/5/8 Alejandro Coca Castro <acocac at gmail.com>

> Hi, i tried to convert the following enviroments settings to GRASS
> g.region and r.mask for the next ARCGIS output (ASCII file):
>
>     fileTIF = r"x:\test\fileTIF.tif"
>     MASK = r"x:\test\mask_file"
>     env.extent = fileTIF
>     env.snapRaster = MASK
>     env.mask = MASK
>     fileGRD = r"x:\test\fileGRD"
>     outCon = Con(fileTIF, fileTIF, "", "VALUE >= 0")
>     outCon.save(fileGRD)
>     fileASC = r"x:\test\fileASC.asc"
>     env.workspace = fileGRD
>     RasterToASCII_conversion(fileGRD,fileASC)
>
> So, i put on the GRASS command-line:
>
> r.mask input=mask_file at default
> g.region rast=fileTIF at default res=0.00208333333 align=MASK at default
> r.mapcalc fileGRD = if(fileTIF at default  < 0 , null(), fileTIF at default)
> r.out.arc input= fileGRD at default output=x:\test\fileASC_grass.asc
>
> However, the ArcGIS and GRASS outputs had a different extend and curiously
> the GRASS output didn't snap their cells with the MASK. Also, when i
> observe the GRASS output cellsize, it only has the first 6 decimals (f.e.
> 0.002083)....
>
> Finally i tried to setup the parameters of g.region with the ArcGIS output
> but GRASS output definetly didnt have the same properties of ArcGIS output
> (cellsize, columns and rows, extend)
>
> If somebody knows how can i fix it, i'll be grateful,
>
> Thanks in advance,
>
> Alejandro
>



-- 
*Alejandro Coca Castro***** ****
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