Hi Nikos:Thanks for your detailed reply! And I know the reason of the problem now. However as what you said,I should create a new location and mapset if necessary,it does not work. I create two folders nLocation/nmapset and create a wind file in the nmapset dir,however when I run the grass gui,I also can not seclect the new location to enter. It throw the error message:the selection location [nlocation ]is not valide. Is the procedure I create the new location is wrong? I followed the maual
maven 2009/6/11 Nikos Alexandris <nikos.alexand...@felis.uni-freiburg.de> > > maven apache: > > When import some raster data to grass,I use the following cmd: > > 1) g.region -d > > This sets to the "default" region which one previously needs to define, > i.e. needs to create with "g.region -s". Please check the manual of > g.region. > > > > 2) r.in.gdal input=D:/test.TIF output=testTT --overwrite > > > I got the error message as following: > > --------------- > > Projection of dataset does not appear to match current location. > >Location PROJ_INFO is: > >name: UTM > >datum: nad27 > [...] > > Import dataset PROJ_INFO is: > > cellhd.proj = 0 (unreferenced/unknown) > > ------------------------ > > That's seems normal. Your test.TIF either isn't georeferenced or it lost > its geotags at some point (after editing with non-GIS tool perhaps?). > > > 3) change the cmd to " r.in.gdal -o input=D:/test.TIF output=testTT > > --overwrite " I know this override the projection,however I am not > > sure the potential effect to the data. > > You should use that only if you _know_ that your test.TIF data are > projected in the system that your grass-location is defined (e.g. > "datum: nad27" as one can see in the error message above). If your data > (test.TIF) are projected in another proj. system expect errors. > > > > Now the tiff is imported,and I got testTT.bule testTT.red > > testTT.green, then I open them can only see blank. So I wonder it is > > caused by the projection or location,I use the spanish data as the > > default location , and I tried to create new location and mapset but > > never success... > > > So, given that test.TIF is in "UTM, datum: nad27" then you need to: > 1. import with r.in.gdal -o (as you already did). > 2. g.region rast=testTT.blue > 3. view your data > > If the test.TIF data are projected in another system you need to: > 1. find out which is that projection system > 2. use some gdal tools to assign the proj. information in the test.TIF > file > 3. define a "new" grass-location based on the projection information of > the test.TIF data > 4. import with r.in.gdal (without the use of "-o" flag) > 5. g.region rast=OneOfTheImportedBands > 6. view, process, etc. > > > Greetings, Nikos > > > >
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