Support 3 band RGB default_cog assets

[anayeaye]

What

Update update_default_summaries(collection_id) delta backend postgres function to handle 3-band RGB assets. RGB assets do not require rescaling on the map so the cog_default raster min/max values are not relevant. I think the correct behavior should be to only create datetime summaries if the cog default assets are multi-band.

Why

The cog_default definition was initally intended for single-band COG assets to be displayed on a dashboard map using a simple rescale factor based on the range of values for all COG assets in the collection. New collections have been encountered with 3-band RGB COG assets that don't fit this criteria but are otherwise the logical default COG layer to render on a map. The update_default_summaries(collection_id) delta backend postgres function expects a single band asset and only returns the min/max of the first band in a raster which is incomplete for 3 band data and summarizing all three bands of 0,255 is not useful for rendering on a map, therefore, raster statistics should be eliminated from the summaries of Collections with 3-band RGB default_cog assets.

Note/Question

This logic will break again as more complex assets are added to the VEDA catalog. In some cases, like HLS, there is no logical default_cog asset to define for the multi-band collection but will we always be able to decide if a collection has a default_cog based on whether or not it has a single band asset or a RGB asset?

Acceptance Criteria

• 3 band RGB assets can be properly ingested into VEDA and viewed through the VEDA dashboard

[aboydnw]

@anayeaye @abarciauskas-bgse are there some datasets that we know about that will be dependent on this work?

@michaelgsuttles maybe we need to understanding if a dataset is single band or 3 band COGs as part of the dataset ingestion workflow?

@ALL, are there other variations like this to consider with datasets? I see @anayeaye mentioned above "as more complex assets are added to the VEDA catalog." What are the other types of complexity and should we create tickets for addressing those at some point?

[anayeaye]

@aboydnw @abarciauskas-bgse @michaelgsuttles Currently we only have one 3 band RGB COG dataset (blue-tarp-planetscope) and it can (and should) be rendered without raster_band statistics. At the time this ticket was created, there was also a 3 band RGB nightlights dataset but that was reprocessed to single band. I think that ultimately there is little value in providing individual band statistics for RGB COGs but I'll leave this open until we have time to discuss.

• Can we strongly recommend that data providers provide single band images for RGB data?
• Should we add some other dashboard property that indicates whether or not band statistics should be calculated? It would be nice if 3 band RGB collections did not have a summary of the first band of an RGB image.

I propose closing this issue as won't fix after discussing.

[aboydnw]

I am game for making this recommendation. If we hear about a ton of datasets or people who this recommendation doesn't work for, then we can adjust later. Before closing this ticket, where is the best place to document that recommendation so people are aware?

[anayeaye]

Maybe in this data provider documentation issue? https://github.com/NASA-IMPACT/veda-architecture/issues/56

[abarciauskas-bgse]

Just acknowledging this thread, creating a best practices guide for data providers is definitely on my radar so thanks for getting that started @anayeaye