Basemap

An item that wraps a single base-layer reference (style URL, tile URL, or WMS). Maps pick one.

basic

A basemap is an item whose body is one reference to a base layer source. It's the bottom layer every map renders against. Streets, satellite imagery, a topographic style, your own tile cache. Maps pick exactly one basemap per item, and the optional basemap-gallery widget lets viewers switch between others at run time.

Basemap sources

A basemap's body is a discriminated union over the source kinds the editor ships today:

  • Style URL. A MapLibre / Mapbox-GL style JSON. The basemap renders that style verbatim. Most public providers (MapTiler, Stadia, OpenFreeMap) expose a style URL.
  • Tile URL. An XYZ tile template (https://.../{z}/{x}/{y}.png). The basemap wraps this as a raster source. Use for tile services that don't publish a style.
  • WMS. A WMS GetMap endpoint plus layer name(s). The basemap renders WMS as a raster source.

The editor also offers Probe (discover layers from a service URL) and From service (pick an existing service item). Those still resolve to one of the kinds above.

A composed-map kind (reuse another map item as the bottom layer) exists in the type union for a later phase and is not authored or selectable in the UI yet. Do not expect a "portal map" basemap picker today.

Where basemaps are picked

  • The map builder has a Basemap selector that lists every basemap the user can read.
  • The org default is a single basemap item the admin pins as the fallback for new maps.
  • The basemap-gallery widget on a web app or dashboard exposes a basemap shortlist to end users.

Attribution

Every basemap can carry an attribution string surfaced in the bottom-right corner of every map that uses it. Most public providers require this. The portal won't silently drop it.

Sharing

Standard three-tier. A public basemap can be referenced from public maps; an org-only basemap restricts the maps that use it.

Notes

  • Multiple basemap stacks aren't supported on a single map. If you need imagery plus a labels overlay plus a parcel outline under your operational layers, add those as ordinary map layers above a single style / tile / WMS basemap — there is no composed-map basemap builder yet.
  • Provider keys belong in the org-level basemap settings, not in the URL. The portal substitutes the key at render time so it doesn't leak into the client.

See also

  • Tile layer. The portal-owned raster/vector tile container (PMTiles) that a tile-URL basemap can point to.