OGC API Features Implementation

This document describes the OGC API Features implementation for the Astral Protocol Location Proof API.

Overview

The OGC API Features standard defines a set of RESTful interfaces to access geospatial data following a standard approach. Our implementation allows accessing location proofs in GeoJSON format with spatial and temporal filtering capabilities.

Endpoints

Landing Page

GET /api/ogc

Returns links to the available resources and API capabilities.

Conformance Declaration

GET /api/ogc/conformance

Lists the conformance classes that the API conforms to.

Collections

GET /api/ogc/collections

Lists the available feature collections.

Collection Details

GET /api/ogc/collections/{collectionId}

Returns detailed information about a specific feature collection.

Features

GET /api/ogc/collections/{collectionId}/items

Returns features from the specified collection. Supports filtering and pagination.

Single Feature

GET /api/ogc/collections/{collectionId}/items/{featureId}

Returns a specific feature from the collection.

Query Parameters

The following query parameters are supported for the features endpoint:

Core Parameters

limit: Maximum number of features to return (default: 10, max: 1000)
offset: Number of features to skip (for pagination)
bbox: Bounding box filter in the format minLon,minLat,maxLon,maxLat
datetime: Temporal filter, can be a specific time or a range:
Specific time: 2023-03-01T12:00:00Z
Time range: 2023-03-01T00:00:00Z/2023-03-31T23:59:59Z
Open-ended range: ../2023-03-31T23:59:59Z or 2023-03-01T00:00:00Z/..

Additional Parameters

chain: Filter by blockchain network (e.g. arbitrum, base, sepolia)
prover: Filter by proof creator address

Response Formats

All responses are in JSON format. Feature responses use the GeoJSON format with appropriate content-type headers.

GeoJSON Features

Features are returned as GeoJSON objects with the following structure:

{
  "type": "Feature",
  "id": "0x...",
  "geometry": {
    "type": "Point",
    "coordinates": [longitude, latitude]
  },
  "properties": {
    "chain": "sepolia",
    "prover": "0x...",
    "subject": "0x...",
    "event_timestamp": "2023-03-01T12:00:00Z",
    "location_type": "DecimalDegrees<string>",
    "revoked": false,
    ...
  }
}

GeoJSON Feature Collections

Feature collections are returned as GeoJSON FeatureCollection objects:

{
  "type": "FeatureCollection",
  "features": [...],
  "links": [...],
  "timeStamp": "2023-03-28T15:23:45Z",
  "numberMatched": 100,
  "numberReturned": 10
}

Example Requests

Get all location proofs

GET /api/ogc/collections/location-proofs/items

Get location proofs within a bounding box

GET /api/ogc/collections/location-proofs/items?bbox=-74.1,40.6,-73.7,40.9

Get location proofs from a specific time range

GET /api/ogc/collections/location-proofs/items?datetime=2023-01-01T00:00:00Z/2023-12-31T23:59:59Z

Get location proofs from a specific blockchain

GET /api/ogc/collections/location-proofs/items?chain=sepolia

Combine multiple filters

GET /api/ogc/collections/location-proofs/items?chain=sepolia&bbox=-74.1,40.6,-73.7,40.9&limit=20&offset=40