Appearance
Filters
kepler's filter panel is unchanged in the panel. What is worth thinking about in a dashboard is which of the two available filters to use — because there are now two, and they behave very differently.
Two places to narrow data
Query filter (WHERE) | kepler filter | |
|---|---|---|
| Runs | in the database | in the browser |
| Rows removed | never leave the database | are still loaded, just hidden |
| Cost of changing it | a query | nothing |
| Can be widened again | yes, re-queries | yes, instantly |
| Affects other panels | if it uses a shared variable | only through cross-filtering |
The rule of thumb: use the query to decide what data comes to the browser, and kepler filters to explore it once it is here.
A kepler filter is a mask. The rows are still loaded, so dragging a slider is free and reversible. That is exactly what you want for exploration, and exactly what you do not want for reducing a hundred million rows to a manageable set.
The time filter
A dataset with a time column gets a time filter with a histogram and a brush. It is the same mechanism as any other filter, with one difference: it carries a fixed domain, so narrowing the brush does not rescale the histogram underneath it.
That property is what makes the Slider writes variables time-sync mode work — the brush stays a mask over the whole dataset, so you can always widen it again. See Time range sync.
Publishing a filter to the dashboard
A select, multi-select or text filter can be bound to a dashboard variable, and a numeric range filter to a pair of them, so filtering the map filters every other panel. This is the two-way channel: changing the variable also applies the filter on the map.
Set it up under Cross-filtering in the panel options, not in kepler's panel — see Cross-filtering.
Polygon filters and the draw tool
A shape drawn with the draw tool can be applied as a polygon filter on a layer. It can also be published to a dashboard variable as WKT, which is a separate thing — the publishing happens as soon as the figure is finished, whether or not you go on to make it a filter. See Publishing the viewport and drawn areas.
Filters are part of the saved configuration
Save current map captures the filters along with everything else, so a dashboard can open with a filter already applied. Worth remembering when a panel appears to be missing data that the query clearly returns — check the filter panel before checking the query.
Upstream: Filters
Written against kepler.gl 3.3.0-alpha.11. See Upstream documentation.