[gdal-dev] Process Sentinel-5p netCDF to tiff files but overlapping appears clearly between 2 files?

[Bang Pham Huu]

Could anyone comment for this problem?

Thanks,

On 11/8/21 1:09 PM, Bang Pham Huu wrote:
> Hello,
>
> I've used 2 Sentinel-5p scenes in hdf5 / netCDF to geoTiff by gdal
> version 2.2.4 like example below:
>
> First, I extract the lat and lon coordinates from one HDF5 file
>
>      gdal_translate -of VRT
> HDF5:"S5P_OFFL_L2__AER_AI_20210501T110005_20210501T124135_18388_01_010400_20210503T005051.nc"://PRODUCT/latitude
> lat.vrt
>      gdal_translate -of VRT
> HDF5:"S5P_OFFL_L2__AER_AI_20210501T110005_20210501T124135_18388_01_010400_20210503T005051.nc"://PRODUCT/longitude
> lon.vrt
>
> Then, I create the product.vrt like below
>
>         <VRTDataset rasterXSize="450" rasterYSize="3735">
>       <Metadata domain="GEOLOCATION">
>         <MDI key="LINE_OFFSET">0</MDI>
>         <MDI key="LINE_STEP">1</MDI>
>         <MDI key="PIXEL_OFFSET">0</MDI>
>         <MDI key="PIXEL_STEP">1</MDI>
>         <MDI key="X_BAND">1</MDI>
>         <MDI
> key="X_DATASET">/home/PROJECTS/Sentinel-5P/test_L2_AER_AI/lon.vrt</MDI>
>         <MDI key="Y_BAND">1</MDI>
>         <MDI
> key="Y_DATASET">/home/PROJECTS/Sentinel-5P/test_L2_AER_AI/lat.vrt</MDI>
>       </Metadata>
>       <VRTRasterBand dataType="Float32" band="1">
>         <Metadata>
>           <MDI key="STATISTICS_MAXIMUM">9.9692099683869e+36</MDI>
>           <MDI key="STATISTICS_MEAN">7.78603750784e+35</MDI>
>           <MDI key="STATISTICS_MINIMUM">-7.209698677063</MDI>
>           <MDI key="STATISTICS_STDDEV">2.6750402750247e+36</MDI>
>         </Metadata>
>         <SimpleSource>
>           <SourceFilename
> relativeToVRT="1">HDF5:S5P_OFFL_L2__AER_AI_20210501T110005_20210501T124135_18388_01_010400_20210503T005051.nc://PRODUCT/aerosol_index_340_380</SourceFilename>
>           <SourceBand>1</SourceBand>
>           <SourceProperties RasterXSize="450" RasterYSize="3735"
> DataType="Float32" BlockXSize="225" BlockYSize="1868" />
>           <SrcRect xOff="0" yOff="0" xSize="450" ySize="3735" />
>           <DstRect xOff="0" yOff="0" xSize="450" ySize="3735" />
>         </SimpleSource>
>       </VRTRasterBand>
>     </VRTDataset>
>
> And finally, I extract the data inside the HDF5 to geoTiff and project
> it to EPSG:4326 CRS.
>
>     gdalwarp -geoloc -t_srs EPSG:4326 -srcnodata 9.96921e+36f
> product.vrt aerosol_index_340_380.tiff -tr 0.069 0.069 -tap -of GTiff
>
> I did that for 2 files which are neighbor to extract the wanted
> sub_dataset to tiff files and then opened them on QGIS.
>
> ** The image looks like below https://imgur.com/uu6pS5n
>
> ** The two extracted tiff files can be found from
> https://drive.google.com/drive/folders/1lOXyJXhhzmfs5e_WTsKPOj96CHEEIyhP?usp=sharing
>
> I wonder, why there are clear borders (the line in the middle) between
> the 2 overlapping files?
>
> Thanks,
>