Encoding and projection for band data
#9
by
rabernat
- opened
Thanks for sharing this great dataset!
I'm trying to understand how the data is structured. I have two questions:
- How is the band data encoded? I gather from the code example that it's just uncompressed binary image data. But what is the dtype? It would be great if this were documented explicitly.
- Where is projection information for each image? The Major-TOM paper recommends "STAC-compliant metadata file describing the assets than can be found in each grid cell".
Thanks!
Hi Ryan!
- Band data is held as a bytestream of a geotif file object, with 16 bit uint values, exactly the same as the original Sentinel-2 images. Good point to add that explicitly in the readme.
- Projection information is currently accessible through the geotif header info for the band data, but we also want to release a geometry-specific metadata table that hold all the projection info in one place, without needing to go into the geotifs. Indeed, STAC metadata for each tile would be nice to implement, and when we released the paper it was anticipated that we would get this done but it's slipped a bit. You can get basic geometry (centroid) from the metadata.parquet table included in the dataset.
There's some examples of accessing the datasets on the Major TOM GitHub. You can have a look here at the first notebook to get some basic functionality and play with the data.