OGC WMTS (Web Map Tile Service) Reader Parameters

WMTS Connection

URL

The URL for the WMTS server. A typical URL specifying a WMTS server looks like:

http://www.mywmtsserver.com/wmts?SERVICE=WMTS&REQUEST=GetCapabilities

Note: This implementation of WMTS supports only Key Value Pair (KVP) encoding. Please ensure that the target WMTS server supports KVP.

Layers

After you have completely specified the connection, click the Browse button to select layers for import. A connection window appears while the system compiles a list from the WMTS server.

Once the layer list appears, you can select one of the layers, and then click OK to dismiss the window. The layer name will appear in the layer list field in the Reader Parameters box.

Use Network Authentication

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

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 Workbench menu, select Tools > FME Options > Network. For more information, see "Network Proxy" in the FME Workbench Help.

Using Web Connections

FME Options: Web Connections

Prefer Dataset URL – This option prioritizes the WMTS source URL to build the GetTile request.

It will not use the defaults from the GetCapabilities result returned by the WMTS server.

Prefer RESTful URL Encoding – This option prioritizes using the REST URL on the GetCapabilities result returned by the WMTS server to build the GetTile request.

If the server does not support REST but supports KVP, then KVP encoding will still be used.

Maximum Number of Concurrent Tile Downloads: The value of this parameter indicates the maximum number of tiles that will be downloaded at the same time. The default value is set to 50.

  • When the parameter is set to 1, a tile download will be fully processed before the next transfer can begin.
  • When the parameter is set to a value greater than 1, the reader will not wait for each transfer to finish before starting the next one. There may be multiple transfers occurring at the same time. This can provide significant performance benefits. This value should be adjusted based on the ability of the WMTS server to handle multiple requests at the same time, taking into consideration that multiple requests increase the load on the server.

Layer Options

Format Options

Click the browse button (...) to open the Select Format Options dialog for selecting the GetTile request format. Select a format and click OK.

Tile Matrix Set Options

Click the browse button (...) to open the Tile Matrix Set Options dialog. Select a tile matrix set option and click OK.

The Tile Matrix Set option allows you to select one of the predefined sets of tiles that the WMTS server provides.

Tile Matrix (Resolution) Options

Click the browse button (...) to open the Time Matrix (Resolution) Options dialog. Select the target resolution and click OK.

The Tile Matrix option allows you to pick the resolution/zoom-level of the returned layer. The higher the resolution, the more tiles need to be retrieved from the server. When choosing a higher resolution, it is recommended to narrow down the area of interest by specifying a Tile Selection Method (refer to Tile Selection Options section for more information).

Style Options

Click the browse button (...) to open the Style Options dialog. Select an Style and click OK.

If not specified, the server uses the default style method specified in the GetCapabilities document. If no default style was specified, the first style option will be selected.

Tile Selection Options

OGC WMTS layers are represented by a variable number of raster tiles depending on the resolution/zoom-level of the request. The WMTS Reader allows you to choose the zoom level by specifying a Tile Matrix which corresponds to a particular zoom-level.

Typically, servers provide an arbitrary scale for zoom-levels (for example, 0 to 20, where 0 provides the least resolution and 20 provides the most resolution). Some servers may have a defined scale (for example, 1000m to 1m, where 1000m provides the least resolution and 1m provides the most resolution).

When choosing a higher resolution, it is recommended to use one of the Selection Types listed below to reduce the number of tiles returned from the server.

WMTS servers divide the layer into a number of tile rows and columns. FME allows you to query specific tile(s) by choosing a selection type.

Selection Type

The Selection Type can be one of four options:

This is the default selection type. All tiles in the layer will be returned.

Selects a single tile at a specific location by referencing the tile row and column:

  • Select Tile Row – The row number of the target tile.
  • Select Tile Column – The column number of the target tile.

Selects a subset of tiles in the layer by referencing a range of tile row and column.

  • Tile Row Min – The lower bound row number of the target tile range.
  • Tile Column Min – The lower bound column number of the target tile range.
  • Tile Row Max – The upper bound row number of the target tile range.
  • Tile Column Max – The upper bound column number of the target tile range.

Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter out the tiles outside of the bounding box. Only the subset of tiles that intersect with or reside in the bounding box are returned.

Note: Tiles that reside on the bounding box boundaries are not clipped or cut off, and will be included in the resulting subset of tiles.

Minimum X – The lower bound x value.

Minimum Y – The lower bound y value.

Maximum X – The upper bound x value.

Maximum Y – The upper bound y value.

Bounding Box Coordinate System – Specifies the coordinate system of the extents given.

Schema Attributes

Use this parameter to expose Format Attributes in Workbench when you create a workspace:

  • In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
  • In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.