OGC API - Maps

OGC API Standards define modular API building blocks to spatially enable Web APIs in a consistent way. OpenAPI is used to define the reusable API building blocks with responses in JSON and HTML.

The OGC API family of standards is organized by resource type. The OGC API - Maps Standard describes an API that presents data as maps by applying a style. The Standard allows a client application to request maps as images, or change parameters such as size and coordinate reference systems at the time of request, making them implementer-friendly and easily understandable by developers without geospatial experience.

Overview of OGC API - Maps - Part 1: Core

OGC API - Maps specifies building blocks for serving maps representing geospatial data through a Web API. These building blocks can be combined with several origins such as the ones suggested in the Origin Conformance Classes. To build a full URL substitute the "..." for the origin URL (e.g., .../map becomes {datasetRoot}/collections/{collectionId}/map).

Get a map
GET .../map
Requests the default representation of the map. Additional parameters can be specified to offer more control on the map being returned.

Specify dimensions
GET .../map?width=600&height=400
Width and height allow you to define the resolution of the returned map.

Spatial subsetting
GET .../map?bbox-crs=[OGC:CRS84]&bbox=160.6,-55.95,-170,-25.89
Geospatial datasets can cover large areas. The Bounding Box (bbox) option allows you to specify a portion of the data for which you wish to retrieve a map. bbox is defined using the bbox-crs specified in the request (defaulting to CRS84 if not specified).

GET .../map?subset-crs=[OGC:CRS84]&subset=Lat(-55.95:-25.89),Lon(160.6:-170)
As an alternative to bbox, the subset query parameter can be used, with a syntax explicitly stating the axis for each bounding coordinate pairs.

Temporal subsetting
GET .../map?datetime=2020-08-20T14:12:05Z
Maps can be obtained for specific date and time.
GET .../map?subset=datetime("2020-08-20T14:12:05Z")
Date and time can also be specified using the subset query parameter.

Styled maps
GET .../styles/{styleId}/map
(In combination with OGC API - Styles) Requests the map to be returned in a specific style. This allows you to define the appearance of the map to suit your needs.

Alternate map CRS
GET .../map?crs=[EPSG:3395]
Maps use Coordinate Reference Systems (CRS) to define their position within a space (e.g., the Earth's surface). OGC API - Maps allows maps to be requested in any CRS supported by the server, and defaults to the native/storage CRS (not necessarily CRS84). This example will return the map according to a World Mercator Projection CRS.

Putting it all together
Multiple parameters can be combined together for a single request, e.g.:
GET .../styles/{styleId}/map?
width=600&height=400&
bbox-crs=[OGC:CRS84]&bbox=160.6,-55.95,-170,-25.89&
datetime=2020-08-20T14:12:05Z&
crs=[EPSG:3395]

GET .../styles/{styleId}/map?
crs=[EPSG:3395]&
width=600&height=400&
subset-crs=[OGC:CRS84]&
subset=Lat(-55.95:-25.89),Lon(160.6:-170),datetime("2020-08-20T14:12:05Z")