OGC API - Features

Lucenia serves its indices as OGC API - Features collections, so a GIS client can open the cluster directly.

Vector tiles draw a map. This serves the features behind it: a click can open a record, QGIS and ArcGIS Pro can connect to the cluster, and OpenLayers or GDAL/OGR can read it without a translating service in between.

The mapping is direct:

Concept	In Lucenia
A collection	An index
A feature	A document
A bounding box	The same shape query the tile endpoint issues
A geometry	Already normalized to GeoJSON by the fields API

Endpoints

GET /_ogc                                                landing page
GET /_ogc/conformance                                    what is implemented
GET /_ogc/collections                                    every collection
GET /_ogc/collections/{collection_id}                    one collection
GET /_ogc/collections/{collection_id}/items              features in a collection
GET /_ogc/collections/{collection_id}/items/{feature_id} one feature

A client is handed the landing page and discovers everything else from its links, so /_ogc is the only URL you need to give it.

note

The service lives under /_ogc rather than the server root because the root already answers with cluster information. The specification does not require otherwise — it only requires that a landing page exist and that the rest be reachable from its links.

Query parameters

On /items:

Parameter	Default	Description
bbox	none	minLon,minLat,maxLon,maxLat. Applied as a query rather than a filter, so the index narrows before anything is read.
limit	10	Features per page. Maximum 10000.
offset	0	Where the page starts.
f	json	Output format.

Connecting a client

Point the client at the landing page:

https://your-cluster:9200/_ogc

In QGIS that is Layer → Add Layer → Add WFS / OGC API - Features Layer, with the landing page as the URL. GDAL/OGR reads the same address:

ogrinfo -ro "OAPIF:https://your-cluster:9200/_ogc"

Authentication is the cluster's own — the endpoints inherit index-read authorization like any other request, so a caller sees exactly the indices they are allowed to read.

What is claimed, and what is not

Conformance is declared honestly, because a class claimed but not implemented produces a client that fails later and further away, where nobody can debug it.

Class	Claimed	Why
core	Yes	The resource model: landing, conformance, collections, items, single item.
geojson	Yes	Features are GeoJSON.
oas30	No	No OpenAPI document is served.
html	No	Responses are JSON, not browsable HTML.
crs	No	Everything is CRS84, the default. There is no CRS negotiation to advertise.

Why not WFS 2.0

Classic WFS is a capabilities document, feature types in XML Schema, queries in the FES filter language and GML on the wire. It is a large specification whose partial implementation fails in real clients in ways that are very hard to diagnose.

OGC API - Features is the same idea over plain HTTP and JSON, and it is what the current generation of clients speaks.

Feature counts

A count is reported when it is exact. Where the search only counted up to its own limit, the response says "at least this many" rather than presenting a bounded count as a total.

Related

• Vector tiles — draw the map; this serves the features behind it
• Geospatial