License Info¶

Together these two attributes allow the administrator to define the contents of the <link rel=license> element in the MapML header. Here is an example of the resulting XML:

<link href=”https://creativecommons.org/licenses/by/4.0/” rel=”license” title=”Attribution 4.0 International (CC BY 4.0)”/>

License Title

The License Title will be included as the value of title attribute of the <link rel=license> element in the MapML header.

License Link

The License Link will be included as the value of href attribute of the <link rel=license> element in the MapML header, and should be a valid URL referencing the license document.

Tile Settings¶

Using tiles to access the layer can increase the performance of your web map. This is especially true if there is a tile cache mechanism in use between GeoServer and the browser client.

Use Tiles

If the “Use Tiles” checkbox is checked, by default the output MapML will define a tile-based reference to the WMS server. Otherwise, an image-based reference will be used. If one or more of the MapML-defined GridSets is referenced by the layer or layer group in its “Tile Caching” profile, GeoServer will generate tile references instead of generating WMS GetMap URLs in the MapML document body.

Client Requests¶

When configuring a cascaded WMS or WMTS remote layers, a new “Client Requests” setting is available.

Remote

If the “Remote” checkbox is checked, the link templates embedded in MapML will refer to the remote WMS/WMTS. The MapML viewer will directly contact the remote server if certain criteria are met:

• No restricting DataAccessLimit security is associated to the layer (e.g. with GeoFence integration) that will do filtering, clipping or similar operations. In that case, the MapML will point to the local GeoServer so that the param is honored.

• No vendor parameters are used in the incoming request. If vendor parameters are used (e.g., request clipping with geometric mask) the MapML is pointing to the local GeoServer so that the vendor parameter is honored

• The remote Server is supporting the requested CoordinateReferenceSystem for that layer.

• GetTile requests will be sent to the remote server if there is a compatible gridset for that layer (same origin, same CRS, same tile sizes, same levels and same resolutions)

Vector Settings¶

MapML supports the serving of vector feature representations of the data. This results in a smoother user navigation experience, smaller bandwidth requirements, and more options for dynamic styling on the client-side.

Use Features

If the “Use Features” checkbox is checked, by default the output MapML will define a feature-based reference to the WMS server. Otherwise, an image-based reference will be used. Note that this option is only available for vector source data. MapML <map-extent> element with a feature link:

<map-extent units="WGS84" label="Manhattan (NY) points of interest" checked="checked">
  <map-input name="z" type="zoom" min="0" max="21"/>
  <map-input name="xmin" type="location" rel="map" position="top-left" axis="longitude" units="gcrs" min="-74.0118315772888" max="-74.00153046439813"/>
  <map-input name="ymin" type="location" rel="map" position="bottom-left" axis="latitude" units="gcrs" min="40.70754683896324" max="40.719885123828675"/>
  <map-input name="xmax" type="location" rel="map" position="top-right" axis="longitude" units="gcrs" min="-74.0118315772888" max="-74.00153046439813"/>
  <map-input name="ymax" type="location" rel="map" position="top-left" axis="latitude" units="gcrs" min="40.70754683896324" max="40.719885123828675"/>
  <map-input name="w" type="width" min="1" max="10000"/>
  <map-input name="h" type="height" min="1" max="10000"/>
  <map-link tref="http://localhost:8080/geoserver/tiger/wms?format_options=mapmlfeatures:true&amp;request=GetMap&amp;crs=MapML:WGS84&amp;bbox={xmin},{ymin},{xmax},{ymax}&amp;format=text/mapml&amp;language=en&amp;version=1.3.0&amp;transparent=true&amp;service=WMS&amp;layers=poi&amp;width={w}&amp;styles=&amp;height={h}" rel="features"/>
</map-extent>

When both “Use Tiles” and “Use Features” are checked, the MapML extension will request tiled maps in text/mapml format. The contents of the tiles will be clipped to the requested area, and feature attributes will be skiipped, as the MapML client cannot leverage them for the moment.

Feature Styling

Basic styling of vector features is supported by the MapML extension. The style is defined in the WMS GetMap request, and the MapML extension will convert the rules and style attributes defined in the SLD into CSS classes and apply those classes to the appropriate features. Note that this conversion is currently limited to basic styling and does not include transformation functions, external graphics, or styling dependent on individual feature attributes (non-static style values). See below for a more detailed compatibility table:

WMS GetMap considerations¶

By default, each layer/style pair that is requested via the GetMap parameters is composed into a single <map-extent>…<map-link tref=”…”>…</map-extent> structure as exemplified above.

If the ‘Represent multi-layer requests as multiple elements’ checkbox from the global WMS Settings page is checked as described above, a request for multiple layers or layer groups in MapML format will result in the serialization of a MapML document containing multiple <map-extent> elements. Each layer/style pair is represented by a <map-extent> element in the response. The <map-extent> elements are represented in the client viewer layer control settings as sub-layers, which turn on and off independently of each other, but which are controlled by the parent <layer-> element’s state (checked / unchecked, opacity etc) (right-click or Shift+F10 to obtain context menus):

With ‘Represent multi-layer requests as multiple elements’ checked, if two or more layers are requested in MapML format via the GetMap ‘layers’ parameter, the MapML extension serialize each layer’s <map-extent> according to its “Use Features” and “Use Tiles” settings. Note that there is currently no “Use Features” setting available for layer groups.

Tile Caching¶

In the Tile Caching tab panel of the Edit Layer or Edit Layer Group page, at the bottom of the page you will see the table of GridSets that are assigned to the layer or layer group.

The values WGS84 and OSMTILE are equivalent to the EPSG:4326 and EPSG:900913 built in GeoWebCache GridSets. However, for the MapML module to recognize these GridSets, you must select and use the MapML names. For new layers or layer groups, or newly created grid subsets for a layer or layer group, the MapML values are selected by default. For existing layers that you wish to enable the use of cached tile references by the MapML service, you will have to select and add those values you wish to support from the dropdown of available GridSets. The set of recognized values for MapML is WGS84 (equivalent to EPSG:4326), OSMTILE (equivalent to EPSG:900913), CBMTILE (Canada Base Map) and APSTILE (Alaska Polar Stereographic).

The MapML client will normally request image tiles against WMTS, but if configured to use feature output, it will try to use tiles in text/mapml format, which should be configured as a cacheable format in order to enable WMTS requests.

Starting with version 2.26.x of GeoServer, Sharding support and related configuration has been removed

Dimension Config¶

Dimension

The selected dimension (if any) is advertised in the mapml as an input with the appropriate value options or ranges, as configured in the Dimension tab of the Layer Configuration page. Only dimensions enabled in the Dimension tab are available as options.

Attribute to <featurecaption> mapping¶

List of attributes The list allows you to read the names of the layer attributes, it doesn’t really do more than that.

Feature Caption Template String

To cause an attribute to be serialized in MapML vector content as the <featurecaption> element value, you must enter its name as a ${placeholder} in the text box immediately below the attributes list. You can also add (a small amount of) plain text that will be copied verbatim into the <featurecaption> content. <featurecaption> is used as the accessible name of features by screen reader software, which will often read out this value without the user having to expand a popup; in other words, it will be used as a visual and audible tooltip when the feature is focused.