On Thu, Jun 14, 2012 at 4:15 AM, Rutger <kass...@gmail.com> wrote: > Hey David, > > > David Hoese wrote >> >> On 6/13/12 10:00 AM, gdal-dev-request@.osgeo wrote >> I'm not sure at the moment, it's VIIRS data. I'm playing around with >> different existing remapping tools, I have one that works called >> ms2gt(ll2cr/fornav) which you might be able to google for the old >> versions, but it's slightly outdated and is single purpose. I would >> like to use GDAL if it can handle it, because of the various formats >> that it supports as output. >> > > I actually already did some test with GDAL geolocation arrays and VIIRS > data. It work flawless for my target area; utm31 for the Netherlands. My > VRT's looked like this: > > lat.vrt > <VRTDataset rasterXSize="6400" rasterYSize="1536"> > <VRTRasterBand dataType="Float32" band="1"> > <Metadata /> > <SimpleSource> > <SourceFilename > relativeToVRT="0">HDF5:GITCO_npp_d20120315_t1208597_e1210238_b01974_c20120321152146856862_noaa_ops.h5://All_Data/VIIRS-IMG-GEO-TC_All/Latitude</SourceFilename> > <SourceBand>1</SourceBand> > <SourceProperties RasterXSize="6400" RasterYSize="1536" > DataType="Float32" BlockXSize="6400" BlockYSize="1536" /> > <SrcRect xOff="0" yOff="0" xSize="6400" ySize="1536" /> > <DstRect xOff="0" yOff="0" xSize="6400" ySize="1536" /> > </SimpleSource> > </VRTRasterBand> > </VRTDataset> > > lon.vrt > <VRTDataset rasterXSize="6400" rasterYSize="1536"> > <VRTRasterBand dataType="Float32" band="1"> > <Metadata /> > <SimpleSource> > <SourceFilename > relativeToVRT="0">HDF5:GITCO_npp_d20120315_t1208597_e1210238_b01974_c20120321152146856862_noaa_ops.h5://All_Data/VIIRS-IMG-GEO-TC_All/Longitude</SourceFilename> > <SourceBand>1</SourceBand> > <SourceProperties RasterXSize="6400" RasterYSize="1536" > DataType="Float32" BlockXSize="6400" BlockYSize="1536" /> > <SrcRect xOff="0" yOff="0" xSize="6400" ySize="1536" /> > <DstRect xOff="0" yOff="0" xSize="6400" ySize="1536" /> > </SimpleSource> > </VRTRasterBand> > </VRTDataset> > > band5.vrt > <VRTDataset rasterXSize="6400" rasterYSize="1536"> > <Metadata domain="GEOLOCATION"> > <MDI key="X_DATASET">lon.vrt</MDI> > <MDI key="X_BAND">1</MDI> > <MDI key="Y_DATASET">lat.vrt</MDI> > <MDI key="Y_BAND">1</MDI> > <MDI key="PIXEL_OFFSET">0</MDI> > <MDI key="LINE_OFFSET">0</MDI> > <MDI key="PIXEL_STEP">1</MDI> > <MDI key="LINE_STEP">1</MDI> > </Metadata> > <VRTRasterBand dataType="UInt16" band="1"> > <Metadata /> > <SimpleSource> > <SourceFilename > relativeToVRT="0">HDF5:SVI05_npp_d20120315_t1208597_e1210238_b01974_c20120316203244033373_noaa_ops.h5://All_Data/VIIRS-I5-SDR_All/BrightnessTemperature</SourceFilename> > <SourceBand>1</SourceBand> > <SourceProperties RasterXSize="6400" RasterYSize="1536" > DataType="UInt16" BlockXSize="6400" BlockYSize="1536" /> > <SrcRect xOff="0" yOff="0" xSize="6400" ySize="1536" /> > <DstRect xOff="0" yOff="0" xSize="6400" ySize="1536" /> > </SimpleSource> > </VRTRasterBand> > </VRTDataset> > > And then reprojection with gdalwarp like: > gdalwarp -s_srs "epsg:4326" -t_srs "+proj=utm +zone=31 +datum=WGS84 > +units=m" \ > -tr 250 250 -te 392875 5574125 808875 5940125 band5.vrt band5.tif > > This works without any errors for me, and the geolocation seems accurate. > But as said, i didnt like the resulting image quality. I have attached a > simple comparison between a gdalwarp nearest neighbor, bilinear and > Pyresample gaussian reprojection. The gdalwarp reprojection seem very > patchy, and the bilinear flag (same with cubic) doesnt seem to have much > affect. Im not sure whether this is to be expected with the current > implementation or if i made any mistakes while specifying the VRT files.
Did you try the other resampling methods - cubicspline and lanczos ? It seems that gaussian resampling is only available for gdaladdo. > > > David Hoese wrote >> >> So I've played around with this for a while now and have gotten >> somewhere. I was able to get data into the geotiff, but with a lot of >> guess work and small tweaking. My t_srs is now: >> "+a=6378137 +lon_1=-95.000 +b=6356752.314 +lon_0=-123.044 +proj=lcc >> +lat_1=25.000 +lat_0=59.844 +ellps=WGS84 +no_defs +wktext +units=m" >> >> All of which are probably not necessary, but at this point it doesn't >> hurt. The origin in that projection is the upper left corner of my >> grid. So I now specify -te as something like: >> "-te 0.0 -5120000.0 5120000.0 0.0" >> >> Which gets me something in the geotiff. I've played around with >> different extents and my best result comes from me manually changing the >> extents to match a picture I have from another system. The grid I'm >> trying to match to is the first one on this page: >> http://www.nws.noaa.gov/noaaport/html/icdtb48_2.html >> >> I have tried using pyproj and plugging in different corner points to get >> the extent points in meters, but when I use those I get skewed images >> (the grid should be 5120 x 5120). >> >> So at this point, I just need to find a way to get the extents figured >> out in a programmatic way (like 1km * 5120 grid pixels = 5120000 >> meters). If you have any more advice that'd be great, otherwise I'll >> just have to keep playing around and asking people around my work. >> Thanks a lot for the help so far. >> >> -Dave >> > > Since it worked for my case, i think its likely that the problems you are > having are related to the projection and area definition. I have no > experience with the AWIPS grid you are mentioning. What i would do in such a > case is to get a sample file with the correct projection and boundingbox, > and just read the metadata with: > gdalinfo -proj4 samplefile.tif > > Optionally add some of the -norat -noct etc flags to hide the large tables. > The proj4 string can be directly used by other gdal tools. > > > Regards, > Rutger > > -- > View this message in context: > http://osgeo-org.1560.n6.nabble.com/gdal-dev-reproject-python-numpy-binary-swath-lat-lon-tp4978609p4981318.html > Sent from the GDAL - Dev mailing list archive at Nabble.com. > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev