MapChart

A choropleth map — regions shaded by value. location names the region column, value the metric. The built-in world map ships offline; point geojson= at a custom GeoJSON (resolved from the project's assets/) for other maps.

<MapChart data={downloads_by_country} location="country" value="downloads"
          map="world" title="Downloads by country" />

From the semantic layer #

Like every chart, MapChart also takes semantic metric refs instead of data={query} — by is the region dimension (its values must match the GeoJSON names) and metric shades each region; map/geojson stay literal:

<MapChart metric={sales.revenue} by={sales.country} map="world" />

Attributes #

Attribute	Purpose
`data`	Required. The query to plot (`data={query}`).
`location`	Required. Region-name column (must match the GeoJSON; alias for `x`).
`value`	Required. Metric that shades each region (alias for `y`).
`map`	Built-in map name (default `world`).
`geojson`	URL/path to a custom GeoJSON for non-world maps (resolved from `assets/`).
`title`	Chart title.
`color`	Single color or comma-separated palette for the scale.
`height`	Pixel height (default `300`).
`col-span`	Columns to span inside a `<Grid>`.
`format` · `currency` · `decimals` · `locale`	Tooltip value formatting.
`empty_message`	Text shown when the query returns no rows.

location/value are aliases for x/y; map/geojson are MapChart-specific. The rest are the shared chart attributes — see Charts.