[Offline imagery] Use Planet NICFI data instead of S2 where available

[gino-m]

One option could be to switch to NICFI at zoom 15 where available, but to keep S2 for lower zoom levels since it has global coverage.

Also requested by @jabramowitz5

[gino-m]

@lecrabe @jo-spek Is there still interest in doing this? Moving to Icebox unless I hear otherwise.

[jo-spek]

@gino-m

I thought we were already using NICFI imagery in some areas. Main problem remains the insufficient zoom levels overall: https://github.com/google/ground-android/issues/1870. Until that one is fixed, this can remain ice-boxed.

[gino-m]

I thought we were already using NICFI imagery in some areas.

Not yet.

Main problem remains the insufficient zoom levels overall: #1870. Until that one is fixed, this can remain ice-boxed.

Ack.

[jabramowitz5]

@jo-spek @gino-m Just noting that the Planet-NICFI agreement for public monthly mosaics has ended (last available mosaic is for February or March 2025). I believe NICFI is currently exploring options to continue their hi-res data program, so there may be updates there soon. However, I still think the Feb/Mar 2025 mosaic will continue to be valuable as recent hi-res imagery for data collectors to orient themselves in the field in the near future.

[gino-m]

@jo-spek Does anyone on your end have time to run the notebooks in notebooks/ against that imagery to produce COGs usable by Ground?

[jo-spek]

I think @rfontanarosa or @lecrabe did that last summer. Doubt they have time for it, but maybe they can comment on what needs to be done?

[jabramowitz5]

Just to update here, the last available Planet NICFI monthly mosaic imagery is April 2025. The full record is still available on GEE. Planet has moved to a paid option for this data going forward called the Tropical Forest Observatory.

[gino-m]

Just to update here, the last available Planet NICFI monthly mosaic imagery is April 2025. The full record is still available on GEE. Planet has moved to a paid option for this data going forward called the Tropical Forest Observatory.

Don't users need to request permission to use those mosaics as well? And how will we refresh the offline imagery once the free ones become stale?

[jabramowitz5]

I was thinking it would work similarly to Collect Earth Online, which made the Planet NICFI imagery available to its users ... however the Planet NICFI historical data is no longer displayed on Collect Earth Online or Global Forest Watch. Perhaps the terms for hosting changed now that the program is officially ended? Not sure, but it seems like might not be the way forward anymore (at least in terms of app having Planet NICFI basemaps readily available for offline download, ie replacing the existing Sentinel 2 data).

Planet NICFI could still be useful (I think April 2025 map still has value for the next year or so ...) as data that users could pull in themselves through GEE (#2827) based on survey creator's own available imagery (they would handle permissions outside of Ground).

We will see if/when NICFI creates their new Satellite Data Program .. to be launched "later this year" - so I think we can put this on pause for now until further notice

[gino-m]

Having Ground pull from Earth Engine is a compelling option.. how would ACLs and billing work in that case? If we don't want the individual users to need to authenticate against Earth Engine, we'd need to create a backend service for the app to talk to to fetch that imagery on behalf of a service account. That service could also verify that the user has access to the survey where that imagery is being provided. Providers of imagery would just need to make sure the service account has access to read the backing EE assets. Note that this would mean the app publisher (FAO) might get billed for Earth Engine access via that service account. Thoughts?

[jabramowitz5]

Not sure if this a a question for me or someone else (I don't know technically how the connection would work or anything about ACL/billing). I would think controlling it at the survey organizer level would make the most sense (not the data collector level). So the survey organizer needs GEE, creates the assets in GEE, and and make them available for their survey using the web platform, then the data collector can download them in that survey for offline use on the mobile app, without needing any interaction with GEE themselves.

Not sure if that is possible, but it the developers of Collect Earth Online at SIG might have some helpful insights here.

[gino-m]

Possible, yes, with varying levels of complexity depending on which path we choose. My two cents:

EE can't directly export the kind of COGs needed by Ground app at the moment (docs), so even if the survey organizer was expert enough to export their own COGs to GCS and make them public, they would need to post-process them with GDAL or similar.

Then there's the question of access control - would survey organizers want to make their bucket public? If not, Ground ACLs would somehow need to be synced with their bucket ACLs (manually?).

Last, but not least - how many survey creators would want to and would be able to create their own offline imagery? If it's on the order of a few dozen users, the juice might not be worth the squeeze.

[jabramowitz5]

1. Ah that is a bummer, I assumed/hoped that it would not be too complicated to export a GEE asset and load that into Ground somehow (similar to CEO or Google Earth displays). This would definitely limit the potential users (already a subset of total users). A guide on how-to do so could be very valuable in the longer term (building off the documentation you shared and experience of whoever produced the current Sentinel-2 mosaics available in Ground). I do think there is value in this capability, but am recognizing the potential high barrier for entry for survey organizers.

2. Not sure on this one

3. I agree it will be a smaller subset of overall users, but I think it could be very powerful for iterative feedback loops for projects like Forest Data Partnership (gather field data, make map, validate map in field, make new map, repeat). I also thought it might alleviate future requests for other offline data options. Instead of the Ground developers needing to make Sentinel-2, Planet, etc. available offline there can be 1 baseline offline imagery product available by default + whatever a user brings in themselves.

Also just to update again on Planet NICFI data - despite the program being ended earlier this year, new data continues to be provided via GEE (latest is currently June 2025) 🤷