GeoJSON / FlatGeoBuf¶
Two vector formats served as a single static file over HTTPS. GeoJSON is
the lingua franca; FlatGeoBuf (.fgb) is its high-performance binary
cousin.
When to use¶
| Format | Use for |
|---|---|
| GeoJSON | Small to mid-size feature collections (≲ a few MB), authoring tools, hand-edited data. |
| FlatGeoBuf | Anything bigger. Streamed via HTTP range requests, indexed for spatial queries — much faster than equivalent GeoJSON. |
Both work as the Data source of a vector layer and as the Statistics source for zonal-statistics overlays on raster layers (see Statistics).
Add a GeoJSON or FlatGeoBuf source¶
Layer Card → Datasets → Add Dataset → Direct Connection. Set Data Format to GeoJSON or FlatGeoBuf and paste the URL.
| Field | Notes |
|---|---|
| Data Source URL | Public HTTPS URL ending in .geojson, .json, or .fgb. |
| Z-Index | Default 50. |
You can also pick the file from an S3 browser — the format is auto-detected from the extension.
Vector fields¶
Once the source is set, open Vector fields (or click Add Fields in the layer card) to auto-populate the field list from the data. The builder reads the first feature for GeoJSON, or the FlatGeoBuf header, and lists all property names with detected types. See Vector fields.
Visualisation¶
Pick one styling tool in the layer card:
- Vector styling — rule-based fills, strokes, point symbols.
- Categories — colour features by a discrete property value.
For polygon layers consider Statistics instead — pre-computed zonal stats are much faster than re-styling on every viewport change.
Validation¶
- The healthcheck issues a HEAD request and confirms the file is reachable and returns the expected content type.
- For FlatGeoBuf, the spatial index is sniffed; un-indexed
.fgbfiles still work but lose the streaming benefit.
Tips¶
- Convert any GeoJSON over a few MB to FlatGeoBuf — same content, an order of magnitude faster.
- Keep property names short and snake_case; they appear unmodified in the deployed Explorer's info panel.
- Strip very large per-feature geometry (multi-thousand-vertex polygons) by simplifying upstream — it speeds up rendering noticeably.