Support xyzservices TileProvider objects in hv.Tiles

Is your feature request related to a problem? Please describe.

With the @geopandas team, we have built a new package called xyzservices to serve as a unified place for XYZ tile management. The idea behind this is that other packages will depend on that instead of having their own system and list of supported tiles hard-coded. It would be great to have holoviews on board with the idea, either by supporting xyzservices.TileProvider as an input of hv.Tiles or even refactoring tiles.py module to depend directly on xyzservices.

xyzservices itself does not have any dependencies which makes it a non-problematic dependency.

It is worth mentioning that xyzservices stores providers’ metadata in JSON under share, accessible for anyone if you have a use case for that.

I am happy to do any changes in xyzservices needed to make it as useful for you as possible if that allows centralising maintenance of providers in one place.

Describe the solution you’d like

1. support TileProvider as an input of hv.Tiles.

import xyzservices.providers as xyz

hv.Tiles(xyz.CartoDB.Positron)

All the info Tiles require can be fetched from the TileProvider object under the hood.

1. refactor tile management

You can remove a big chunk of the maintenance burden by refactoring tile management in tiles.py using xyzservices directly. In the first step, you can remove all metadata and simply map your existing classes to TileProvider objects. In the second, you can even dynamically support the whole xyzservices library of providers instead of the pre-defined set you have now.

Describe alternatives you’ve considered

I know that 2) may sound like a bit ambitious proposal but 1) is pretty straightforward to implement already. So I’d say that having at least the first part would be nice.

Additional context

Support of xyzservices is being implemented across the ecosystem, from geopandas’ own packages (new built-in foilum-based plotting and contextily) to leafmap (https://github.com/giswqs/leafmap/issues/91) and ipyleaflet (https://github.com/jupyter-widgets/ipyleaflet/issues/854) (+ hopefully more).

If there’s anything we would need to implement in xyzservices to make all this work, I am all ears.

It seems that @philippjfr would welcome that 😃.

[jlstevens]

Thanks @martinfleis for the suggestion!

Interestingly enough, @jbednar @philippjfr and myself recently discovered xyzservices and briefly discussed this suggestion already!

It is good to have an issue opened though and from what I remember, we were thinking that xyzservices could be an optional dependency that could be used instead of replacing the existing tile source definitions. I don’t why we couldn’t support xyzservices in the constructor as in suggestion 1.

Suggestion 2 would be a bigger effort that I think we should consider (especially as we recently had issues with the wikipedia tile source no longer being public available). While that might need some discussion, I don’t think anyone will object to suggestion 1 right now.

If you are willing to make a PR on HoloViews implementing suggestion 1, that would be much appreciated! My only request would be that this is coordinated with a corresponding PR in GeoViews (as we want to maintain a consistent API between the two projects).

[xTerma]

@xTerma @jlstevens @jbcrail #4651