OGC API – Features Reader Parameters

Note   The source dataset must be a URL to the server’s JSON Landing page or the server’s JSON Collections resource.

Use Network Authentication

Note  This parameter is always visible in some formats, and visible in other formats only when the dataset is a URL.

Authentication Method

Specify the authentication method to use when accessing a password-protected server.

  • Basic (default) – Basic access authentication is designed to allow a client to provide credentials to a server on the assumption that the connection between them is trusted and secure. Note that any credentials passed from client to server can be easily intercepted through an insecure connection.
  • Digest – Digest authentication is one of the agreed-upon methods a web server can use to negotiate credentials, such as username or password, with a user's web browser.
  • NTLM – A challenge-response protocol that is used to provide compatibility with versions of Windows earlier than the Windows 2000 operating systems.
  • Web Connection – Web connections provide a convenient and secure way to store and reuse previously established connection parameters. See Web Connection below.
  • Single Sign-on – FME will use the credentials of the current user to authenticate the HTTP request. This authentication method currently works only on the Windows operating system.
Note  To access datasets using a proxy server, use the Network tools in FME Options. From the FME Workbench menu, select Tools > FME Options > Network. For more information, see "Network Proxy" in FME Workbench Help.

Web Connection

Using Web Connections

FME Options: Web Connections

Note  To access datasets using a proxy server, use the Network tools in FME Options. From the FME Workbench menu, select Tools > FME Options > Network. For more information, see Network Proxy in FME Workbench Help.

Connection Properties

Select this option to use the HTTP Post method to update the databases.

If your WFS service requires you to identify yourself via user-agent, you can select this option to override the default FME HTTP User-Agent.

This parameter can be used to set a timeout on HTTP connection requests. If a connection to the server cannot be created within the given number of seconds, the request fails, and the reader is not added.

The default connection timeout is 90 seconds. If 0 is entered, there is no timeout, and the reader waits indefinitely for a successful connection.

This parameter can be used to set a timeout on HTTP transfers. If data stops being transferred for more than the given number of seconds, the request fails and the reader is not be added.

The default transfer timeout is 90 seconds. If 0 is entered, there is no timeout, and the reader waits indefinitely for data to resume being transferred.

Constraints

Collections

Collections correspond to Feature Types in FME. This parameter lets you browse and select Collections for which to generate Feature Types.

The collections are gathered from server’s Collections resource.

This table can be used to configure the URL query strings for the requested collections. The URL query strings specified in this table are sent when requesting the first page of a collection, but they are not sent for subsequent next page links.

Special reader-specific parameters (which start with the _ogcapi_ prefix, such as _ogcapi_max_features_) are used to control reader operations and are not sent to the server as part of the URL query string.

Each row in the table represents a single query parameter that may be applied to one, to several, or to every collection selected in the Collections parameter.

There are three columns in this table:

Column Name

Description

Collection(s)

The values must be one of the selected collections in the Collections parameter. If left unset, then the specified query parameter in the row applies to every collection.

Parameter Name

 The name of the query parameter. The specified parameter must be supported by the server. Common OGC-API Feature parameters are bbox, bbox-crs, datetime, limit, and start-index.

URL query parameters:

  • bbox – Used to select a subset of features in the collection by specifying coordinates of a bounding box containing the features. By default, the bbox parameter expects a bounding box in the default Coordinate Reference System (CRS), unless another CRS is specified in the parameter bbox-crs.
  • bbox-crs – Used to specify an alternate bbox CRS.
  • datetime – Used to select a subset of features in the collection by specifying an associated timestamp.
  • limit – Controls the page size (the number of features returned per response).
  • start-index – Specifies within the collection an index from which to begin presenting features.

Non-URL query parameters:

  • _ogcapi_max_features_ – This is a reader-specific parameter to limit the number of features specified. The parameter is not sent to the server – instead, the reader will stop processing documents for a particular collection once max features has been reached.

Parameter Value

The value of the query parameter. The value should be valid for the query. For example:

If the query is bbox, then its value should be four or six comma-separated numbers:

ll1,ll2,min-3,ur-1,ur-2,max-3

where:

  • ll1 is the lower left corner for coordinate axis 1
  • ll2 is the lower left corner for coordinate axis 2
  • min-3 is the optional minimum value for coordinate axis 3
  • ur is the upper right corner for coordinate axis 1
  • ur is the upper right corner for coordinate axis 2
  • max-3 is the optional maximum value for coordinate axis 3

For example:

bbox=-123.08,49.05, -122.25,49.37

The bbox query values should be in WGS 84 longitude/latitude unless a different crs is specified with the bbox-crs query (which is identified by a URI).

If the query is start-index then its value should be a non-negative number. For example, start-index=500.

Additional Parameters

Add ogcapi_source_url Attribute

Adds the ogcapi_source_url attribute to every feature read. The value of the attribute is the URL that was used to retrieve a collection from the server.