Support OGC API - Features

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The Spec

This issue is to track adding full support for the OGC API - Features spec as well as any discussion around the process.

The spec currently includes 5 parts with parts 4 and 5 currently under draft. The initial plan will be to support Part 1: Core with others as follow up tasks. I currently do not expect us to support Part 2 which adds CRSs which Cesium already does not do much work with.

• OGC API - Features - Part 1: Core corrigendum, version 1.0.1 standard
  • Latest Editor's Draft of next version of OGC API - Features - Part 1: Core
  • ISO 19168-1:2020 Geographic information - Geospatial API for features - Part 1: Core standard
• OGC API - Features - Part 2: Coordinate Reference Systems by Reference corrigendum, version 1.0.1 standard
  • Latest Editor's Draft of next version of OGC API - Features - Part 2: CRS by Reference
• OGC API - Features - Part 3: Filtering, version 1.0.0
• OGC API - Features - Part 4: Create, Replace, Update and Delete draft
• OGC API - Features - Part 5: Schemas draft

Format/Encoding

The spec does not mandate any specific encoding or format but strongly favors HTML and GeoJSON with additional suggestions for GML. We will focus the initial implementation only around GeoJSON (especially since we already support it) with other formats being optional secondary efforts in the future as requested.

Side note: the API does not dictate a specific way to designate what format to serve. I believe most servers will implement this with the content type in headers but another suggestion from the Spec is to use a f=[format] query parameter which I've observed utilized in other libraries and servers so my current assumption is this is one of the more generally accepted methods.

Other implementations

Just listing off some other implementations I've found. Mainly from this list

• ogcapi-js - lightweight and focused on the Features API
  • Works well but I don't see any way to control authentication beyond adjusting query params for every request. May not work with header auth?
• ogc-client - supports multiple OGC specs
  • Similar auth concerns. Allows setting global fetch options for the whole client which could make it hard to use multiple sources
  • The API seems more focused on exploring a service completely and may not fit our needs and use case as closely
  • Only works in browser as it relies on window internally

Example data

Just an assortment of data sources from servers that we know support the OGC Features API and we can use for testing during implementation

• National Land Survey of Finland seems to have a bunch of data
  • Free but needs an API key - Instructions for using the API key
  • Geographic names (OGC API Features)
  • Technical description – Topographic Database (OGC API Features)
• https://demo.ldproxy.net/ Demos using ldproxy but has a handful of different data that we can view
  • Data has a mix of areas, lines and points which is useful
  • Supports an HTML representation so it's really easy to explore the data without another viewer. Just add ?f=json to get the GeoJSON representation
  • Some of these are very large datasets, for example this one of road network nodes has over 10,000 points which could be useful for stress testing or any loading optimizations
• ArcGIS also seems to have OGC Features as an option but I have not explored it much yet
  • We may be able to use the API key we already use
  • Work with OGC Features services—ArcGIS Server | Documentation for ArcGIS Enterprise
  • Tutorial: Style features | CesiumJS | Esri Developer
• Please mention more if you know of good ones!