Timeline Facet

[dleadbetter]

There are two main goals here. The first is an mvp.

• It should be possible to filter search results (places) on a map, based on the dates in their related events. A slider facet would allow the user to set an earliest start date and a latest end date, and typesense should return only places for which the events match those values. Places which also have events outside those values should be included. Places which have no related events, or only related events with dates outside those values should not.
• It should be possible to see a timeline visualization on the bottom of the map viewport, which extends the width of the viewport, and for which the earliest year and latest year are set by the earliest and latest dates of all events associated with all places in the index. On the timeline, we should see either one point for each event (perhaps start date), and/or a "span" or "range" element for events with a span or range of dates. Since there may be many events, there would have to be some kind of aggregation or stacking UI, so that we can at least see areas of greater/lesser event density, or better yet, we can see all events, stacked vertically when they overlap. Event labels could be hidden by default, and revealed only on hover or click. Events and their related places on the map and in the result sidebare should be visually linked, as results and map points are now -- hover on one highlights the other.