Hi Steven, So the issue here is that gdal_translate doesn’t properly store the +sweep=x in the geotiff.
See http://geotiff.maptools.narkive.com/3CqwNeMd/geos-projection-sweep-parameter <http://geotiff.maptools.narkive.com/3CqwNeMd/geos-projection-sweep-parameter> for some relevant discussion. I believe the best solution right now is to specify the s_srs in the gdalwarp command like -s_srs "+proj=geos +lon_0=-75 +h=35786023 +x_0=0 +y_0=0 +ellps=GRS80 +units=m +no_defs +sweep=x" This is a bit of a mess, sorry about that. Zac > On Mar 20, 2018, at 9:37 PM, Steven Beale <steven.be...@woodplc.com> wrote: > > Hi gdalers, > > I'm a little out of my field here, usually I work with weather/climate data, > but I need to warp some goes16 satellite data. (source is aws s3: > https://noaa-goes16.s3.amazonaws.com/ABI-L2-CMIPF/2018/079/12/OR_ABI-L2-CMIPF-M3C01_G16_s20180791200447_e20180791211214_c20180791211280.nc > - the link should work for a few months then it will be glaciered and > unavailable) > > source data is netcdf, I'm using nco tools & gdal for the processing. > > My work flow is: > 1. clip the data to the region of interest (north atlantic): > ncks -d x,5424,8678 -d y,0,2170 <raw.nc> step1.nc > 2. deflate & unscale > gdal_translate -ot float32 -unscale -CO COMPRESS=deflate NETCDF:step1.nc:CMI > step2.tiff > 3. warp (in this case data is 1km resolution : ~0.009 degrees) > gdalwarp -t_srs EPSG:4326 -dstnodata -999.0 -tr 0.009 0.009 -te 290 40 320 > 65 -r near step2.tiff step3.tiff > 4. convert back to nc > gdal_translate -ot float32 -of NETCDF step3.tiff output.nc > > The problem i have is that the output has the longitude shifted to the west > by about 10 degrees. > The issue seems related to the ncks clipping, if I exclude the x clip, > everything works out fine, but takes significantly longer. > Here's an example once it's loaded into an erddap server; > <http://osgeo-org.1560.x6.nabble.com/file/t382897/GOES16_L2CMIPF_M3C01_201803201200.png> > > You can see greenland to the west of it's map underlay. > > I'm using gdal v2.3.0, netcdf v4.4.1.1, nco v4.7.3 & proj4 v5.0.0 > > > > > > -- > Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev
_______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
