Place boundary

# Show a place's boundary polygon on a map > Search a place with geolith, fetch it by gid with geometry=true, and draw its outline on a MapLibre map, falling back to the bounding box when the place has no outline. --- title: Show a place's boundary polygon on a map description: Search a place with geolith, fetch it by gid with geometry=true, and draw its outline on a MapLibre map, falling back to the bounding box when the place has no outline. date: '2026-10-22' tags: [maplibre, polygons, javascript] minutes: 12 steps: - name: Search the place text: Call /v1/search with layers=locality or layers=region and keep the gid of the first result. - name: Fetch it with geometry=true text: Call /v1/place?ids=&geometry=true. Places with an outline return a Polygon or MultiPolygon. - name: Draw it text: Add the feature as a GeoJSON source with a fill and a line layer, then fit the map to its bbox. - name: Fall back to the bbox text: When the geometry is a Point, draw the bbox as a rectangle and fit the map to it. faqs: - q: Which value does geometry take? a: true or false. Other values such as 1 are rejected with HTTP 400 ("geometry must be true or false"). - q: Which places have outlines? a: Countries, regions, counties, localities and venues that are mapped as areas. - q: Can I store the polygon? a: Yes. geolith results may be stored permanently; keep the attribution where you display them. --- To show a place's boundary on a map with geolith, search it with `/v1/search`, fetch it by its `gid` with `GET /v1/place?ids=&geometry=true`, and add the returned GeoJSON feature to a MapLibre map as a fill layer. With `geometry=true`, the API returns a `Polygon` or `MultiPolygon` for countries, regions, counties and venues mapped as areas, with the original point in `properties.center`. Some places, such as cities mapped only as a point, have no outline; the code below draws the outline when there is one and the bounding box when there is not. ## The two requests ```bash # 1. Find the place, keep its gid curl "https://api.geolith.app/v1/search?text=maharashtra&layers=region&size=1" \ -H "Authorization: Bearer YOUR_API_KEY" # -> features[0].properties.gid = "geolith:region:13395044029" # 2. Fetch it with its outline curl "https://api.geolith.app/v1/place?ids=geolith:region:13395044029&geometry=true" \ -H "Authorization: Bearer YOUR_API_KEY" ``` ## The page `boundary.html`. Use a **publishable** key (`gc_pk_...`) that allows the page's origin. ```html Place boundary

``` Serve it over HTTP (for example `npx serve .`) so the browser sends an `Origin` header your key allows. ## Notes - `MultiPolygon` outlines (islands, enclaves) draw with the same two layers; nothing changes. - With `geometry=true`, an area keeps its point in `properties.center`, so you can still drop a label there. - To show many areas at once, pass up to 40 gids in `ids`, comma-separated. - Coverage is worldwide: try `France` with *Country*, or `Bavaria` with *State / region*. Get a free API key: https://console.geolith.app/signup