Landing page and conformance

Topolab implements OGC API - Features Part 1: Core, a standard HTTP interface for serving geospatial features as GeoJSON. Any OGC-compatible client, QGIS, ArcGIS, GDAL/OGR, can read Topolab data directly by pointing at the base URL, with no custom integration.

The OGC API is rooted at:

https://api.topolab.nl/v1/ogc

Two discovery endpoints are anonymous, no API key is required: the landing page (/v1/ogc) and the conformance declaration (/v1/ogc/conformance). Everything beyond discovery, the collections list and every feature, needs an organization API key with the GIS_ACCESS addon in the X-API-Key header; see Authentication.

What OGC API - Features is

OGC API - Features is an OGC standard that defines a small, predictable set of resources: a landing page, a conformance declaration, a list of collections, and the features within each collection. Because the contract is standardized, a GIS client can discover everything it needs at runtime, it reads the conformance declaration, then crawls the links, and present Topolab datasets as live layers it can pan, zoom, and query.

This is why GIS users do not need an SDK: the client speaks the protocol. For the application-developer view of the same data over plain REST, see the Datasets API.

Landing page

The landing page is the entry point. It returns the service title, a description, and links to the other resources.

curl "https://api.topolab.nl/v1/ogc"

{
  "title": "Topolab OGC API - Features",
  "description": "Geospatial features for Topolab datasets, served as OGC API - Features.",
  "links": [
    {
      "rel": "self",
      "type": "application/json",
      "title": "This document",
      "href": "https://api.topolab.nl/v1/ogc"
    },
    {
      "rel": "conformance",
      "type": "application/json",
      "title": "Conformance declaration",
      "href": "https://api.topolab.nl/v1/ogc/conformance"
    },
    {
      "rel": "data",
      "type": "application/json",
      "title": "Collections",
      "href": "https://api.topolab.nl/v1/ogc/collections"
    },
    {
      "rel": "service-desc",
      "type": "application/vnd.oai.openapi+json;version=3.0",
      "title": "OpenAPI definition",
      "href": "https://api.topolab.nl/v1/ogc/api"
    }
  ]
}

A client follows the rel values: conformance to learn what the server supports, data to list collections, and service-desc for the OpenAPI document.

Conformance declaration

The conformance endpoint lists the conformance classes the server implements. A client reads this to decide which requests it may make. Topolab declares exactly three classes:

curl "https://api.topolab.nl/v1/ogc/conformance"

{
  "conformsTo": [
    "http://www.opengis.net/spec/ogcapi-features-1/1.0/conf/core",
    "http://www.opengis.net/spec/ogcapi-features-1/1.0/conf/geojson",
    "http://www.opengis.net/spec/ogcapi-features-1/1.0/conf/oas30"
  ]
}

These three classes mean: the service implements OGC API - Features Part 1 Core, serves features as GeoJSON, and describes itself with OpenAPI 3.0. There is no CQL or advanced-filtering conformance class, so the only server-side filters are bbox and the category, city, and country attribute parameters documented in bbox and filtering.

OpenAPI document

The api endpoint returns the OpenAPI 3.0 description of every operation, parameter, and response. Tooling can generate clients from it, and it is the machine-readable companion to these docs.

curl "https://api.topolab.nl/v1/ogc/api"

The response is a standard OpenAPI 3.0 document. The interactive paths it describes, /collections, /collections/{collectionId}/items, and so on, are documented in the following pages.

Connecting a GIS client

Because these endpoints are standard, you can add https://api.topolab.nl/v1/ogc as an OGC API - Features data source in QGIS or ArcGIS and browse Topolab collections directly. The landing page and conformance declaration are open, so a client can discover the service anonymously; listing collections and reading features requires an organization API key with GIS_ACCESS in the X-API-Key header, plus a license for each dataset you access. See the QGIS plugin guide for connection steps.

Next

• Collections, list the datasets available as feature collections.
• Items, page through the features in a collection.
• Need a key with GIS_ACCESS? Get in touch.