On Wed, May 9, 2012 at 4:07 PM, Alejandro Coca Castro <[email protected]> wrote: > Hi, i share an image where the display n.1 shows the non-align between the > Arcmap ASCII and the output Grass ASCII which was created by the r.out.arc > function. > > I think the problem is in this step... . As you can observe in the display > n.2, the output grid of r.mapcalc function is aligned with the Arcmap ASCII, > but it loss the g.region properties when it is exported. Finally, i checked > the properties of the output grid of r.mapcalc with the g.region -g function > and it retained the same extend and resolution of Arcmap ASCII... > I think instead of r.out.arc, you can also use r.out.gdal format=AAIGrid and see if that gives a better match.
Markus M > Mark, i set the region as you tried... > > Thanks in advance, > > > > 2012/5/9 Markus Metz <[email protected]> >> >> On Tue, May 8, 2012 at 9:41 PM, Alejandro Coca Castro <[email protected]> >> wrote: >> > Hi Mark, i followed your instructions, so i put in command-line >> > >> This >> > g.region rast=MASK@default nsres=0:00:07.5 ewres=0:00:07.5 >> >> will adjust, i.e. modify the resolution in order to fit into the >> extents. The extents are not modified. In GRASS, the extents have >> precedence over resolution, unless you use the -a flag, in which case >> the extents are aligned to the desired resolution. Thus use either >> >> g.region rast=MASK@default nsres=0:00:07.5 ewres=0:00:07.5 -a >> >> to align the current region to the desired resolution and enforcing >> this resolution, or >> >> g.region rast=MASK@default >> >> You can check if the current region is all right with g.region -p or >> g.region -g, before doing any processing. >> >> I tried to set the region with the gdalinfo output of the ArcMap >> raster fileASC_ARCMAP.asc: >> >> g.region w=-60.9250001 e=-49.9979167 n=-0.0000001 s=-10.0000001 >> res=0.00208333333 >> >> Output of g.region -g: >> n=-1e-07 >> s=-10.0000001 >> w=-60.9250001 >> e=-49.9979167 >> nsres=0.00208333333333333 >> ewres=0.00208333334604385 >> rows=4800 >> cols=5245 >> cells=25176000 >> >> As you can see, the resolution needed to be adjusted, i.e. there are >> floating point rounding errors in fileASC_ARCMAP.asc. Using rounded >> DD:MM:SS.S format: >> >> g.region w=60:55:30W e=49:59:52.5W n=0 s=10S res=00:00:07.5 >> >> Output of g.region -g: >> n=0 >> s=-10 >> w=-60.925 >> e=-49.9979166666667 >> nsres=0.00208333333333333 >> ewres=0.00208333333333333 >> rows=4800 >> cols=5245 >> cells=25176000 >> >> This is probably the desired extents and resolution, the resolution >> did not need to be adjusted (0.00208333333333333 = 00:00:07.5) . >> >> Markus M >> >> > >> > 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 <[email protected]> >> >> >> >> 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@default >> >> g.region rast=fileTIF@default res=0.00208333333 align=MASK@default >> >> r.mapcalc fileGRD = if(fileTIF@default < 0 , null(), fileTIF@default) >> >> r.out.arc input= fileGRD@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 > > > > > -- > Alejandro Coca Castro > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
