Show projected data on maps

[sophiamersmann]

Core problem

• When dealing with projected data, authors usually include two indicators, one for historical data, one for future projections
• Line charts stitch them together, but maps do not (see screenshots below)

Example chart: https://ourworldindata.org/grapher/population-growth-rates

Proposed solution

Maps should combine past and future data, if both are available. Probably needs some design work: What visual cue are using to differentiate between past and future data?

[larsyencken]

It makes me wish for a different internal data model for projected data, like a pair of time series, one of values and one saying if it's a projection or not.

It's not clear what strategy would be good for indicating it. A shift in title? A different tooltip?

@danyx23 Perhaps whether or not a data point is projected would be a good hidden dimension for a dimensional indicator.

[github-actions]

This issue has had no activity within 10 months. It is considered stale and will be closed in 7 days unless it is worked on or tagged as pinned.

[danyx23]

I think we should build this. This issue has the needs-design label but I think if we chat about it in the next data viz triage we could come up with an approach for this and do this. Some of these maps are very useful IMHO