MapML¶

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.

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).

Sharding Config¶

The Sharding Config options are intended to allow for parallel access to tiles via different server names. The actual server names must be configured in the DNS to refer to either the same server or different servers with the same GeSserver layer configuration. In the example above, the mapML client would alternate between the servers a.geoserver.org, b.geoserver.org, and c.geoserver.org to access the map images. The values in the example above would result in the following MapML:

<input name="s" type="hidden" shard="true" list="servers" min="0.0" max="0.0"/>
<datalist id="servers">
    <option value="a"/>
    <option value="b"/>
    <option value="c"/>
</datalist>
<link tref="http://{s}.geoserver.org:8080/geoserver/test/wms?version=1.3.0&amp;service=WMS&amp;request=GetMap&amp;crs=EPSG:3857&amp;layers=cntry00&amp;styles=&amp;bbox={xmin},{ymin},{xmax},{ymax}&amp;format=image/png&amp;transparent=false&amp;width={w}&amp;height={h}" rel="image"/>

Enable Sharding

If Enable Sharding is checked, and values are provided for the Shard List and Shard Server Pattern fields, then a hidden shard list input will be included in the MapML.

Shard List

If Enable Sharding is checked, the Shard List should be populated with a comma-separated list of shard names which will be used to populate the shard data list element.

Shard Server Pattern

The Shard Server Pattern should be a valid DNS name including the special placeholder string {s} which will be replace with the Shard Names from the Shard List in requests to the server. This pattern should not include any slashes, the protocol string (http://) or the port number (:80), as these are all determined automatically from the URL used to access the MapML resource.

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.