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Hi Shao: In order to post, you must sign up for this email list at http://www.unidata.ucar.edu/support/mailinglist/mailing-list-form.html#subscribe Also, you should not post files larger than a 100Kb. Put the file on a web server and send a link to it. thank you address@hidden wrote: > > Subject: > process swath data by netCDF > From: > Yuanzheng Shao <address@hidden> > Date: > Thu, 12 Feb 2009 16:29:26 -0500 > To: > address@hidden > > To: > address@hidden > CC: > address@hidden > > > Hi everyone, > My aim is to extract the visible and infrared imagery from the DMSP/OLS > 'smooth' data (with the format of OIS). Because the OIS belongs to swath > data, I think the current GridDatatype is unsuitable to process this format. > Definitely using the method "ucar.nc2.FileWriter.writeToFile", we can get the > corresponding netCDF file and we can view the visible and infrared imagery of > the netCDF file in NetCDF Tools. > > Then I want to write the geotiff with GeotiffWriter, but it failed because > the the axis in this file is unequally spacing (lat, lon). That's why the > GeotiffWriter throws an exception at GridCoordSystem.isRegularSpatial(), the > exception info was "Must have 1D x and y axes for infraredImagery". So it > seems that I can not get the geotiff file from the generated netCDF file. > > So I changed to use gadl_translate tools to generate geotiff file. The good > news was I got the geotiff files and these files can be viewed correctly. The > bad news was that when I path this geotiff file with gdalinfo, it displayed > that this file was not a valid geotiff, without the Coordinate System. > > My question is how could extract different band from the swath data and write > them to geotiff? Does netCDF can perform this task? If I can not achieve this > aim only by netCDF, can anyone give me some suggestion? > Maybe convert swath into grid is a effect method, but I have not found any > tools could do this. > > I also attached my sample data, which include the original OIS data, the > generated nc file by netCDF, and the gerated tif files by gdal_translate. > > Many thanks. > > Yuanzheng Shao > CSISS, George Mason University > 6301 Ivy Lane, Suite 620 > Greenbent, MD 20770 > TEL:571-480-3560 >