Geographic rendering

MapLibre is the sole geographic renderer for built-in LeapView visuals. ECharts owns non-geographic analytical charts; ECharts geo is not a fallback renderer for maps.

Runtime boundary

MapLibre owns projection, camera state, basemap sources and layers, geographic hit testing, clustering, spatial gestures, layer ordering, and map snapshots. The visualization IR remains renderer independent: authors cannot provide MapLibre styles, ECharts options, callbacks, or remote tile URLs.

LeapView owns the geographic asset package, including its pinned OSM-derived PMTiles archive, style, glyphs, sprites, provenance, license, attribution, and digests. Assets use immutable same-origin URLs and are verified before serving.

The governed runtime owns inline result budgets and spatial-windowed queries. The browser requests a bounded viewport and never receives authority to query arbitrary data sources. Chart-like glyphs on a map are closed, typed geographic layers inside the MapLibre lifecycle rather than a second interactive canvas.

Product guarantees

• Compatible data and selection updates preserve the current camera.
• Map rendering recovers from WebGL context loss without relaxing data policy.
• Every map exposes an accessible tabular equivalent.
• Shared formatting, theme, legend, tooltip, accessibility, and interaction contracts also apply to custom geographic layers.
• Geographic packages are content addressed and never replaced at an existing URL.

Adding a second built-in geographic renderer requires a new architecture decision and evidence for a product surface that cannot be expressed as a typed MapLibre layer.