Querying features

Two queries answer “what’s here?”. Both take a target in braille dots relative to the map area (2 per column, 4 per row).

let dot = ((col - area.x) as f64 * 2.0 + 1.0, (row - area.y) as f64 * 4.0 + 2.0);

What’s drawn here

let hits = map.query_rendered_features(&cam, area, dot, None);
let pins = map.query_rendered_features(&cam, area, dot, Some(&["pins"]));

Like MapLibre’s queryRenderedFeatures: features drawn under the target, top layer first and, within a layer, points before lines before polygons. Pass layer ids to search only those. Custom layers answer through their pick.

Everything here

let all = map.query_features(&cam, area, dot);

Every feature of every source under the target, drawn or not: this is what the viewer’s inspect mode shows. Sources come in the order of their topmost layer; within a source, points, then lines, then polygons from smallest to largest. Each result says whether a layer draws it.

Pick

Both return Vec<Pick>:

Field
layer	The source layer ("transportation", "poi", or the GeoJSON source)
style_layer	The style or custom layer that draws it, if any
drawn	Whether a shown layer draws it
source	The map source id
tile	The vector tile it came from (None for GeoJSON)
geom	Point, line or polygon
props	All properties, in order
lonlat	Geometry in lon/lat: points, lines or polygon rings
stats	Measurements: center, length or area, vertex count

Helpers: prop("name"), title() (a good one-line name), kind(), and to_json(), the same JSON that mapterm --pick prints.