# geojson.app

> A free, open-source web map for viewing, exploring and sharing GeoJSON — with 3D terrain, timelines, satellite imagery and guided map stories. Everything a person can do by clicking, an agent can do with a link or the embed SDK. No account, no API key.

geojson.app runs entirely in the browser. Data you open by URL is fetched by the viewer's browser (the source must allow CORS); data you drop in never leaves the device. Features follow RFC 7946 GeoJSON, and styling follows the simplestyle-spec (`stroke`, `fill`, `marker-color`, …).

## Open data with a link

Every parameter works on `https://geojson.app/?…`. Parameter names are a frozen v1 contract.

- `geojson=<url>`: load a GeoJSON `Feature` or `FeatureCollection` and fit the map to it. Example: `https://geojson.app/?geojson=https://example.com/data.geojson`
- `center=<lng>,<lat>` and `zoom=<0–22>`: initial camera. Example: `?center=85.3,27.7&zoom=11`
- `theme=light|dark|white|grayscale|black` and `projection=mercator|globe`: appearance
- `story=<name-or-url>` and `chapter=<index-or-id>`: open a guided map story. Example: `?story=bhotekoshi-2026`
- `embed=1`, `chrome=full|minimal|none`, `interactive=true|false`, `attribution=visible|compact`: embed behaviour

## Embed and drive a live map

Load `https://geojson.app/embed.js` (~2 kB gzipped, no dependencies). It exposes `window.GeoJSONApp`:

```html
<div id="map" style="height: 450px"></div>
<script src="https://geojson.app/embed.js"></script>
<script type="module">
  const map = GeoJSONApp("create", { element: "#map", geojson: "https://example.com/data.geojson" });
  await map.ready();
  await map.flyTo({ center: [85.3, 27.7], zoom: 11 });
  map.on("click", ({ lngLat, features }) => console.log(lngLat, features));
</script>
```

Methods (all return Promises): `flyTo`, `jumpTo`, `fitBounds`, `setTheme`, `setProjection`, `setGeoJSON`, `addLayer`, `removeLayer`, `clearLayers`, `listLayers`, `setLayerVisibility`, `getCenter`, `getZoom`, `getBearing`, `getBounds`, `addImagery`, `removeImagery`, `listImagery`, `setTerrain`, `setTime`, `setCompare`, `loadStory`, `setStoryChapter`.
Events: `load`, `move`, `moveend`, `click`, `theme:change`, `projection:change`, `story:chapter`, `error`.
The iframe speaks postMessage protocol v1 (envelope `{ source: "geojson.app.embed", v: 1, … }`), so any client that can post messages can drive it without the SDK.

## Docs

- [Developer API](https://github.com/bishalspkt/geojson-app/blob/main/docs/developers-api.md): full SDK and postMessage reference, error codes, recipes
- [Embedding guide](https://github.com/bishalspkt/geojson-app/blob/main/docs/embed.md): quick start and options
- [Integrations](https://github.com/bishalspkt/geojson-app/blob/main/docs/integrations.md): URL parameters, SDK, and the planned MCP server
- [Stories](https://github.com/bishalspkt/geojson-app/blob/main/docs/stories.md): the story document format (chapters, camera, layers, terrain, timelines, before/after imagery)

## Optional

- [Source code](https://github.com/bishalspkt/geojson-app)
- [Architecture](https://github.com/bishalspkt/geojson-app/blob/main/docs/architecture.md)