OGC API

The OGC API is a standards-based, read-only REST view of the same layers the OGC services (WMS/WFS) expose. It implements OGC API Features (Part 1 Core and Part 2 CRS) for reading features as GeoJSON and OGC API Maps (Part 1 Core) for rendered map images — so any client that speaks the OGC API standards (QGIS, GDAL/OGR and others) can browse and read your data with no Centia-specific code.

Every layer with OGC services enabled is a collection, identified as schema.table. Features are served by the same WFS engine and maps by the same WMS backend as the classic services, so privileges, geofence rules, versioning and workflow all apply. The API is read-only — write with the Feature API, SQL or WFS-T.

All routes are GET under a database-qualified base URL:

https://api.centia.io/api/v4/ogc/database/{database}

Route	Returns
`/`	Landing page with links: `conformance`, `data` (collections), `service-desc` (OpenAPI)
`/conformance`	The conformance classes the API implements
`/collections`	All collections visible to the caller (`limit` default 100, max 1000)
`/collections/{id}`	One collection: title, description, `extent`, `crs` list, `storageCrs`, links
`/collections/{id}/items`	The features as a GeoJSON `FeatureCollection`
`/collections/{id}/items/{fid}`	One feature as a bare GeoJSON `Feature`
`/collections/{id}/map`	A rendered map image of one collection
`/map?collections=a,b`	A rendered map image of several collections (same schema)

Requests are authenticated like the classic OGC services: Bearer token (must belong to {database}), HTTP Basic, or anonymous for publicly readable layers.

Collections

/collections lists what the caller may read — protected layers are simply omitted for callers without access. Each collection carries its spatial extent (in CRS84), the list of supported CRS URIs and, for versioned layers, a temporal extent. Raster layers appear as map-only collections without an items link:

Request
GET https://api.centia.io/api/v4/ogc/database/mydb/collections/rockhall.venues HTTP/1.1
Accept: application/json
Authorization: Bearer abc123

Items

/collections/{id}/items returns the features as a streamed application/geo+json FeatureCollection. The response carries numberMatched (the total), numberReturned, and next/prev links for paging; the CRS of the returned geometry is echoed in the Content-Crs header:

Request
GET https://api.centia.io/api/v4/ogc/database/mydb/collections/rockhall.venues/items?limit=2 HTTP/1.1
Accept: application/geo+json
Authorization: Bearer abc123

Response
{
    "type": "FeatureCollection",
    "numberMatched": 25,
    "timeStamp": "2026-09-11T12:00:00Z",
    "features": [
        {
            "type": "Feature",
            "id": 1,
            "geometry": {
                "type": "Point",
                "coordinates": [-118.3856, 34.0906]
            },
            "properties": {
                "venue_id": 1,
                "name": "Whisky a Go Go",
                "city": "West Hollywood"
            }
        },
        {
            "type": "Feature",
            "id": 2,
            "geometry": {
                "type": "Point",
                "coordinates": [-118.3893, 34.0816]
            },
            "properties": {
                "venue_id": 2,
                "name": "The Troubadour",
                "city": "West Hollywood"
            }
        }
    ],
    "links": [
        { "rel": "self", "type": "application/geo+json", "title": "This document", "href": "..." },
        { "rel": "collection", "type": "application/json", "title": "The collection", "href": "..." },
        { "rel": "next", "type": "application/geo+json", "title": "Next page", "href": "..." }
    ],
    "numberReturned": 2
}

Parameters:

limit — page size, default 10, max 10000 (higher values are clamped). offset skips features; follow the next link to page through everything.
bbox — minx,miny,maxx,maxy in the axis order of bbox-crs. A lower corner above the upper corner is rejected with 400 (no antimeridian boxes).
crs / bbox-crs — CRS URIs from the collection's crs list, not bare EPSG codes:
- http://www.opengis.net/def/crs/OGC/1.3/CRS84 — the default, lon/lat.
- http://www.opengis.net/def/crs/EPSG/0/4326 — lat/lon axis order (per the standard), both in bbox input and GeoJSON output.
- http://www.opengis.net/def/crs/EPSG/0/{code} — projected CRSs, x/y.
Anything else is 400 (INVALID_CRS).
datetime — a single ISO 8601 instant (e.g. 2024-01-01T00:00:00Z). On a versioned layer it selects the version valid at that time; on other layers it is ignored. Intervals are not supported (400).

Unknown query parameters are rejected with 400 (UNKNOWN_PARAMETER), as required by OGC API Common.

Get one feature

/items/{fid} returns a bare GeoJSON Feature (with links), or 404 if it does not exist. It accepts only crs, datetime and f:

Request
GET https://api.centia.io/api/v4/ogc/database/mydb/collections/rockhall.venues/items/1 HTTP/1.1
Accept: application/geo+json
Authorization: Bearer abc123

Maps

/collections/{id}/map renders the collection as an image through the WMS backend, styled with the layer's classes, styles and labels:

Request
GET https://api.centia.io/api/v4/ogc/database/mydb/collections/rockhall.venues/map?bbox=-118.5,33.9,-118.2,34.2&width=1024&f=png HTTP/1.1
Authorization: Bearer abc123

Parameters:

bbox / bbox-crs / crs — as for items; bbox defaults to the collection's extent.
width / height — 1 to 16384 pixels. Give one and the other follows the bbox aspect ratio; give none and the width is 1024.
f — png (default, transparent background) or jpeg (opaque).
transparent / bgcolor — background control; bgcolor as 0xRRGGBB.
datetime — as for items, on versioned layers.

The dataset-level /map?collections=a,b renders several collections in one image — they must belong to the same schema (400 otherwise):

Request
GET https://api.centia.io/api/v4/ogc/database/mydb/map?collections=rockhall.venues,rockhall.tours&width=1024 HTTP/1.1
Authorization: Bearer abc123

Access and errors

The per-layer access model is the same as for WMS/WFS: anonymous callers read layers whose authentication level is None or Write; Read/write layers require credentials and, for sub-users, a privilege other than none (group inheritance applies). Note the distinction between the codes — 404 always means unknown, never hidden:

Status	Meaning
`400`	Bad or unknown parameter, invalid CRS URI, interval `datetime`, items on a raster collection, mixed schemas in `/map?collections=`.
`401`	The collection exists and is protected, and the request is anonymous — answered with a `WWW-Authenticate: Basic` challenge.
`403`	The identity is known but lacks privilege on the collection, or a geofence rule denies the request.
`404`	Unknown collection or feature (`COLLECTION_NOT_FOUND` / `FEATURE_NOT_FOUND`).
`502`	The map rendering backend failed, e.g. a missing mapfile (`MAP_BACKEND_ERROR`) — always JSON, never an HTML error page.

Using the SDK

The @centia-io/sdk (0.2.13+) wraps the API in the Ogc class. Feature properties can be typed, CRS URIs are built with the exported OGC_CRS84 constant and ogcEpsgCrs() helper, and errors are thrown as CentiaApiError with .status and .code. Map images are fetched by URL — use mapUrl/datasetMapUrl to build URLs for <img> tags or map libraries:

import { createCentiaClient, Ogc, OGC_CRS84, ogcEpsgCrs } from '@centia-io/sdk'

const ogc = new Ogc(createCentiaClient({ baseUrl, auth: { getAccessToken } }))

const { collections } = await ogc.getCollections('mydb')
const collection = await ogc.getCollection('mydb', 'rockhall.venues') // extent, crs list, links

// GeoJSON items — default page size is 10; follow the `next` link or pass offset
const page = await ogc.getItems<{ venue_id: number; name: string }>('mydb', 'rockhall.venues', {
  bbox: [-118.5, 33.9, -118.2, 34.2], // lon/lat in CRS84 (the default bbox-crs)
  crs: ogcEpsgCrs(25832),             // output CRS from the collection's crs list
  limit: 100,
})
page.numberMatched // total; page.numberReturned; page.links (next/prev)

const feature = await ogc.getItem('mydb', 'rockhall.venues', 1)

// Map images are fetched by URL (e.g. an <img> or a map library)
const url = ogc.mapUrl('mydb', 'rockhall.venues', {
  bbox: [-118.5, 33.9, -118.2, 34.2],
  width: 512,
  format: 'png',
})
const multi = ogc.datasetMapUrl('mydb', ['rockhall.venues', 'rockhall.tours'], { width: 512 })

Collections​

Items​

Get one feature​

Maps​

Access and errors​

Using the SDK​