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Resource: Feature

Version: 1.0.1

Overview

A feature. Every feature is a sub-resource of an OGC Collection.

Maturity: Mature

Pre-defined properties

Table 1. Properties
Property Type Description

links

[ Link ]

REQUIRED. Links to other resources. See Link relation types for typical link relations of this resource type.

id

string or integer

REQUIRED. The feature identifier in the collection.

In addition, there will be properties that describe the real-world entity that the feature represents plus optionally properties that are metadata.

Link relation types

The following link relation types are commonly used in links from a Feature:

Table 2. Outgoing link relation types
Link relation type Description

self

REQUIRED. Link to the resource in the current representation.

alternate

REQUIRED. Link to the resource in every other media type supported by the server.

collection

REQUIRED. Link to the OGC Collection that this feature belongs to.

describedby

Refers to a resource providing information about the data, for example, a schema for the feature or a separate metadata resource.

type

Refers to the canonical URI of a feature type that the feature implements.

canonical

Refers to a persistent URI of this feature that will not change between API changes.

The following link relation types are commonly used in links to a Feature:

Table 3. Incoming link relation types
Link relation type Description

item

May by used to point to the feature from a static OGC Collection resource.

Representation: GeoJSON

The GeoJSON representation is the currently recommended representation that all APIs should support, where GeoJSON can be used for the data.

In addition to the pre-defined properties listed above, each GeoJSON feature includes the following JSON members:

  • type: fixed value "Feature".

  • geometry: the primary geometry of the feature describing its location as a GeoJSON geometry object. null, if the feature has no spatial geometry.

  • properties: an object with a member for each feature property.

Example

The Barra airport feature from OS Open Zoomstack 
{
   "type":"Feature",
   "links":[
      {
         "href":"https://demo.ldproxy.net/zoomstack/collections/airports/items/8?f=json",
         "rel":"self",
         "type":"application/geo+json",
         "title":"This document"
      },
      {
         "href":"https://demo.ldproxy.net/zoomstack/collections/airports/items/8?f=html",
         "rel":"alternate",
         "type":"text/html",
         "title":"This document as HTML"
      },
      {
         "href":"https://demo.ldproxy.net/zoomstack/collections/airports?f=json",
         "rel":"collection",
         "type":"application/json",
         "title":"The collection the feature belongs to"
      }
   ],
   "id":8,
   "geometry":{
      "type":"Point",
      "coordinates":[
         -7.4485984,
         57.0255697
      ]
   },
   "properties":{
      "name":"Barra Airport"
   }
}

Media type

application/geo+json

Representation: HTML

Providing an HTML representation is recommended so that the resource can be displayed in a web browser and indexed by search engines.

The HTML representation should include all information that is part of the JSON representation.

Media type

text/html