Make StationLookup a proper Mapping

[dopplershift]

Description Of Changes

This allows iteration, membership, etc. directly on the station information rather than needing to use the tables property. The abstract base class gives us some things like get(), keys(), and values() for free.

Checklist

• Addressing some of MetPy's new StationLookup features in Google Colab #2397
• Fixes Add station_info to docs #2343
• Tests added
• Fully documented

[dopplershift]

@jthielen Do you think it would be enough to have a docstring example of use here? Of course, station_info and StationLookup don't seem to show up in our reference pages atm. Or did you have a more proper gallery example in mind?

[jthielen]

@jthielen Do you think it would be enough to have a docstring example of use here? Of course, station_info and StationLookup don't seem to show up in our reference pages atm. Or did you have a more proper gallery example in mind?

Yes and yes? Having StationLookup in the API reference with a docstring example (and description of where this info is from) was my initial thought, but having a gallery example would be nice as well. Given that we have geopandas in the doc environment, for the latter I was thinking a demo loading the station info into a GeoDataFrame and then applying some example spatial operation? I should be able to put something like that together quick tomorrow.

[dopplershift]

Ok, I added StationLookup and station_info to the docs for metpy.io, and I added a brief docstring example.

I'll leave a proper example to later, when I can come up with something useful--or if you get some cycles to breathe life into your idea @jthielen .

[dcamron]

Looks nice and helpful! Small change for docs render. Also, question: are instances exported with the Exporter context manager supposed to automatically end up with generated doc summaries? If so, I'm not seeing that here after a quick glance.

[dopplershift]

Exporter's primary mission in life is managing __all__. Sphinx doesn't appear to do anything with instances, and so far I haven't found any magic incantations to change that. I suppose we could implement a custom module template. 😬

[dcamron]

I think I'm very okay skipping that and calling the explicit shoutout in the class docstring good enough!