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1

So after discussing this problem with other developers in Gdal-Dev mailing list it turned out that MODIS swath data can not be perfectly re-projected by using gdalwarp. It is because of bow-tie effect of the MODIS scanning sensor which gdal can not deal with. The best option is to download associated geolocation datasets (MOD03) and use MRTswath for ...


1

If you need a raster with a fixed resolution in meters, you have to reproject your data in a projected CRS, like UTM, Lambert conformal conical or what might be used in Australia. While degrees of latitude have more or less the same size in meters, one degree of longitude decreases from the equator towards the poles, where it is almost zero. So it makes ...


6

Nice and reproducible question. Personally, I'd expect that the reason for the difference is in the implementations of the bilinear reprojection. You can obviously look into source code for the two approaches, but I'd expect that to be a vast overkill. It appears that the R implementation introduces bigger "errors" / "changes" than the raw GDAL version ...


0

One easy workaround would be to specify the coordinate system "manually" as a PROJ string. This allows you to use the +over switch that disables wrapping on the antimeridian: gdalwarp -t_srs \ "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0 \ +over +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null \ +wktext +lon_wrap=-180 +no_defs" ...


2

After some testing, I think that the geoloc is not working properly. So I used the alternative method using manually created vrt files: Create a file named lon.vrt: <VRTDataset rasterXSize="1354" rasterYSize="2030"> <SRS>GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS ...


0

Usually I specify -s_srs and -t_srs (source and destination projection system) you can either reference a proj4 name or provide the path to a .prf file, or specify manually your projection parameters. I suspect this might be the cause of your problem since it doesn't seem you ever defined the reference system of your gcp. The GUI might be doing this for you ...


2

gdalwarp had a problem projecting the poles using this projection. The solution came from AndreJ above which pointed me to clip the polar regions out of the input data. I ran the following commands which made it work: >> gdal_translate -projwin -180 80 180 -80 topo30.ers topo30_no_poles.tif >> gdalwarp -s_srs WGS84 -t_srs ogcwkt.prj -r near ...



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