<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Steven,<div class=""><br class=""></div><div class="">So the issue here is that gdal_translate doesn’t properly store the +sweep=x in the geotiff.</div><div class=""><br class=""></div><div class="">See <a href="http://geotiff.maptools.narkive.com/3CqwNeMd/geos-projection-sweep-parameter" class="">http://geotiff.maptools.narkive.com/3CqwNeMd/geos-projection-sweep-parameter</a> 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"</div><div class=""><br class=""></div><div class="">This is a bit of a mess, sorry about that.</div><div class=""><br class=""></div><div class="">Zac<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Mar 20, 2018, at 9:37 PM, Steven Beale <<a href="mailto:steven.beale@woodplc.com" class="">steven.beale@woodplc.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Hi gdalers, <br class=""><br class="">I'm a little out of my field here, usually I work with weather/climate data,<br class="">but I need to warp some goes16 satellite data. (source is aws s3:<br class=""><a href="https://noaa-goes16.s3.amazonaws.com/ABI-L2-CMIPF/2018/079/12/OR_ABI-L2-CMIPF-M3C01_G16_s20180791200447_e20180791211214_c20180791211280.nc" class="">https://noaa-goes16.s3.amazonaws.com/ABI-L2-CMIPF/2018/079/12/OR_ABI-L2-CMIPF-M3C01_G16_s20180791200447_e20180791211214_c20180791211280.nc</a><br class="">- the link should work for a few months then it will be glaciered and<br class="">unavailable) <br class=""><br class="">source data is netcdf, I'm using nco tools & gdal for the processing. <br class=""><br class="">My work flow is: <br class="">1. clip the data to the region of interest (north atlantic): <br class="">ncks -d x,5424,8678 -d y,0,2170 <raw.nc> step1.nc <br class="">2. deflate & unscale <br class="">gdal_translate -ot float32 -unscale -CO COMPRESS=deflate NETCDF:step1.nc:CMI<br class="">step2.tiff <br class="">3. warp (in this case data is 1km resolution : ~0.009 degrees) <br class="">gdalwarp -t_srs EPSG:4326 -dstnodata -999.0 -tr 0.009 0.009 -te 290 40 320<br class="">65 -r near step2.tiff step3.tiff <br class="">4. convert back to nc <br class="">gdal_translate -ot float32 -of NETCDF step3.tiff output.nc <br class=""><br class="">The problem i have is that the output has the longitude shifted to the west<br class="">by about 10 degrees. <br class="">The issue seems related to the ncks clipping, if I exclude the x clip,<br class="">everything works out fine, but takes significantly longer. <br class="">Here's an example once it's loaded into an erddap server; <br class=""><http://osgeo-org.1560.x6.nabble.com/file/t382897/GOES16_L2CMIPF_M3C01_201803201200.png> <br class="">You can see greenland to the west of it's map underlay. <br class=""><br class="">I'm using gdal v2.3.0, netcdf v4.4.1.1, nco v4.7.3 & proj4 v5.0.0 <br class=""><br class=""><br class=""><br class=""><br class=""><br class="">--<br class="">Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html<br class="">_______________________________________________<br class="">gdal-dev mailing list<br class="">gdal-dev@lists.osgeo.org<br class="">https://lists.osgeo.org/mailman/listinfo/gdal-dev</div></div></blockquote></div><br class=""></div></body></html>