Clustering member data by political geographies

[janbaykara]

This PR provides statistical data on member lists at the regional / constituency / council / ward levels, dependent on the user's current zoom, so that we are always providing some kind of insight for the current view.

As part of this work, the codebase now ingests Region, Constituency and Ward geographies for the whole of the UK, and in PostGIS format unlike before.

The scene is set for geography explorer panels and other interactive map features.

Motivation

Displayed member data was previously scattered across the map like a grain truck that's tipped over onto the road.

How Can It Be Tested?

1. Re-build the dev container if you haven't already, as we've switched to PostGIS
2. Import the required geo data:
   • python manage.py import_areas
   • python manage.py import_regions
   • python manage.py import_wards
3. Connect a data source of the type Member - make sure it has postcodes!
4. Make a report and add a map layer via the data configuration option in the top left
5. As you zoom far to near, you should see geographical regions and their aggregate counts.
6. At the nearest zoom level, individual member pins should be displaying.

You can also run the import tests to verify that data is indeed importing.

Screenshots (if appropriate):

Types of changes

• New feature (non-breaking change which adds functionality)

[linear]

MEEP-206 Level 2.5: geo-clustering layers by political geographies

[render]

Your Render PR Server URL is https://meep-intelligence-hub-frontend-pr-28.onrender.com.

Follow its progress at https://dashboard.render.com/web/srv-cnstglgl6cac73av45f0.

[conatus]

This looks really solid. I've got some minor comments I think would be good to be fixed, but it seems in a good place.

[conatus]

As a note over at upstream mysociety#506 they are working at pulling in council data.

I feel like this might be complementary to the work done here to bring in councils, but here in a slightly different way due to PostGIS.

[conatus]

I am presuming here @janbaykara that wards are shuffling between constituencies, but the boundaries of the wards remain the same in the 2019 electoral map?

[janbaykara]

I am guessing so but haven't researched this @conatus.

I've seen ward data 2023, 2022, 2021 etc so I think they may change a lot more frequently than constituencies; plausible they'll change again to align with the 2024 election?

On the other hand, wards are the electoral unit for council elections not for constituency elections, so also plausible and perhaps more likely that they won't change...