add schema for landCover, base theme

[Jonah Adkins (jonahadkins)]

Proposal

Add multiple resolutions of global land cover data to base theme in Overture (sometime in 2024). Examples below from Meta's production basemaps.

Low Resolution, minZoom=0, maxZoom=4

Medium Resolution, minZoom=4, maxZoom=9

High Resolution, minZoom=9, maxZoom=24

Background

The Display Maps team at Meta recently completed a project to integrate global land cover data into it's basemaps. Landcover data provides an opportunity o display continuous, gapless representation of the Earth's natural surfaces. We derived these products from the 2020 European Space Agency (ESA) raster land cover product. Our process was generally: (1) download the image tiles, (2) process them, (3) vectorize them, and finally (4) post-process them to a usable format for vector tiling. We publicly released these with our Daylight product last year (Blog).

For Discussion

(1) IMO this is a huge opportunity for Overture to provide a massive dataset, critical to every global basemap used in a multitude of mapping applications. This would be a first-of-its kind public dataset, it's hard to develop for day-to-day mappers, and is a huge technical lift at global scale.

Examples of land cover in production across several providers.

(2) Providing multiple resolutions meets the needs of map developers and cartographers who would use this data in their workflows. We could provide only the highest resolution, but users would need to develop complex processes to generalize and simplify the data. Providing only medium or low resolution would fall short of expectations for this type of dataset.

Providing tile zoom recommendations is probably a better way to define resolution than a specific reference scale like 1:1,000,000 or text like 'medium'.

(3) This is typically a "one and done" type dataset. This type of data is generally only needs refreshing every 5 to 10 years, and adding metadata such as year and source helps define that.

(4) While this type of data can be found in OpenStreetMap, this product provides continuous coverage across the globe.

[Victor Schappert (vcschapp)]

This sounds great!

I feel like the right place to initially have this discussion is within the base theme Task Force. Once they're aligned that:

1. this is a good thing to do; and
2. we can generate and provide the data once the schema is merged;

then we should push forward with it...

[Jonah Adkins (jonahadkins)]

I feel like the right place to initially have this discussion is within the base theme Task Force.

thanks Victor Schappert (@vcschapp) - this PR is the result of discussion in that task force last week

[BoZivk]

Shouldn't this be referenced within schema/schema.yaml?

[Jonah Adkins (jonahadkins)]

Victor Schappert (@vcschapp) / Jennings Anderson (@jenningsanderson) / Jacob Wasserman (@jwass) / BoZivk
i think this is ready to go (finally)

The base branch was changed.

[Victor Schappert (vcschapp)]

Can we add a couple of examples and counter-examples specific to the land_cover feature type?

[Jennings Anderson (jenningsanderson)]

Jonah Adkins (@jonahadkins) Wasn't there a version of this where min-max zoom level was expressed instead as a scale?

[Jonah Adkins (jonahadkins)]

Jonah Adkins (@jonahadkins) Wasn't there a version of this where min-max zoom level was expressed instead as a scale?

originally, but we thought it was more confusing

[Jacob Wasserman (jwass)]

Looking forward to getting this out there!

[Jacob Wasserman (jwass)]

PR for data license approval: https://github.com/OvertureMaps/tf-data-platform/pull/253

[Victor Schappert (vcschapp)]

In schema meeting 2024-05-01, Jacob Wasserman (@jwass) indicated including ESA WorldCover for use as landcover is OK by legal. So this is not a blocker for merging.