* Nikos Alexandris <[email protected]> [2020-10-02 12:32:31 +0200]:
According to `gdalinfo`, MOD021KM (and MYD021KM for the matter), list identical bands under two different subdatasets (SDSes). For example, SDS 3 (see `gdalinfo`'s report on it https://gitlab.com/thermopolis/public/code/-/snippets/2021406) and SDS 24 (see `gdalinfo`'s report on it https://gitlab.com/thermopolis/public/code/-/snippets/2021407), both contain essentially the same data/bands. The obvious differences between the two SDSes are the descriptive name (SDS 3 contains the characteristic, for this product, word 'SWATH') and the set of ground control points (GCP) (SDS 24 does not list any GCPs along). I've search in every related official document I can find on-line about MOD021KM products. I can't trace anything related to my question so far (see for example: - https://ladsweb.modaps.eosdis.nasa.gov/filespec/MODIS/61/MOD021KM - https://mcst.gsfc.nasa.gov/sites/default/files/file_attachments/M1054E_PUG_2017_0901_V6.2.2_Terra_V6.2.1_Aqua.pdf - https://mcst.gsfc.nasa.gov/sites/default/files/file_attachments/MODIS_L1B_ATBD_ver8_finalupload.pdf (although not the document that would expectedly contain details about the subdatasets in MOD02 products) ). Panoply (https://www.giss.nasa.gov/tools/panoply/), however, contains only once the set of Emissive bands at 1KM, and the same for the rest of data (see https://i.imgur.com/llGYVfo.png). What is the difference between the two SDSes?
I am forwarding NASA's reply on the matter: " Following up to your yesterday's information, we discussed this entirely. We do not have access to gdal and would need more effort installing and familiarizing with it. Generally, there is only one dataset "EV_1KM_Emissive" in MOD021KM/MYD021KM data file, and it resides in "MODIS_SWATH_Type_L1B". To our best guess, gdal reads subdataset list at swatch layer, grid layer and SDSs. That is why there are duplicated subdatasets shown in the list, but they belong to SWATH layer and SDS, respectively. Regards, LAADS User Services Ticket Details --------------------------------- Ticket ID: 108294 Department: LAADS DAAC Type: General Status: Waiting for User Priority: Low " I find it a bit confusing to have duplicate data reported by gdalinfo. Cheers, Nikos _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
