Use ecoregions data

[tschaub]

This branch replaces the use of the current countries dataset with data from the RESOLVE Ecoregions 2017 dataset.

See the updated examples. I'm curious if people think these load or render too slowly.

• vector layer
• box selection
• export map
• geojson-vt
• select features
• hit detection
• image vector
• Sphere Mollweide

The new https://github.com/openlayers/data repo is a place where we can host data for our examples. Yes, data in git is not fun, but these are the benefits:

• Commits to that repo are hosted at https://openlayers.org/data/*
• CORS
• gzip
• We can make tweaks to the data before hosting

Fixes #12940
Closes #12941
Closes #12942

[github-actions]

📦 Preview the examples and docs from this branch here: https://deploy-preview-13177--ol-site.netlify.app/.

[mike-000]

In a map export there is no reason (apart from a very un-obvious assertion if you don't set a className on one of the layers) why you couldn't have a semi-opaque vector layer with background over another layer as in https://codesandbox.io/s/export-map-forked-cmdk1?file=/main.js The backgroundColor should therefore be applied to the mapContext after the globalAlpha is set. I think it would be helpful to keep a tile layer to demonstrate that.

[tschaub]

The backgroundColor should therefore be applied to the mapContext after the globalAlpha is set.

Good point. I adjusted the example to do this.

I think it would be helpful to keep a tile layer to demonstrate that.

I don't agree with this part. I think it is unfortunate that our examples tend to get more complex and uglier over time, as people add new functionality or fix issues and tack features on to existing examples as a way to demonstrate the change to themselves. While the changes likely make sense to the author, I don't think this makes the examples more useful.

I can imagine it would be useful to add a map.export({type, quality}) method (that would throw in cases where we cannot generate a data URL). Then we could push the complexity from this example into that method. And we could have tests that assert that things work with layer background, opacity, etc.

[ahocevar]

Thanks for this huge effort, @tschaub!