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Geomajas WMS layer plug-in Table of Contents
List of Tables
List of Examples
This plug-in contains a raster layer definition for accessing raster
data from WMS servers. It has support for WMS versions (1.0.0, 1.1.0, 1.1.1
and 1.3.0)
Since version 1.8.0 of this plug-in, there is also built-in support
for basic and digest HTTP authentication. On top of this, the option remains
to add user name and password parameters as GET parameters to each WMS
GetMap request.
A command exists to access the GetFeatureInfo request which is
available on some WMS servers.
Table of Contents
Make sure sure you include the correct version of the plug-in in
your project. Use the following excerpt (with the correct version) in the
dependencyManagement section of your project:
<dependency>
<groupId>org.geomajas.plugin</groupId>
<artifactId>geomajas-server-layer-wms-parent</artifactId>
<version>1.16.2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
If you are using geomajas-project-server to manage dependencies, this includes the latest released
version of the wms layer (at the time of publishing of that version). If
you want to overwrite the caching plug-in version, make sure to include
this excerpt before the geomajas-project-server dependency.
You can now include the actual dependency without explicit
version.
Example 2.1. WMS layer dependency
<dependency>
<groupId>org.geomajas.plugin</groupId>
<artifactId>geomajas-layer-wms</artifactId>
</dependency>
For using these functionalities in GWT or GWT2 client,
see the specific client documentation.
A complete WMS layer configuration looks as follows:
Example 2.2. WMS layer configuration
<bean name="wmsBluemarbleInfo" class="org.geomajas.configuration.RasterLayerInfo">
<property name="crs" value="EPSG:4326"/>
<property name="maxExtent">
<bean class="org.geomajas.geometry.Bbox">
<property name="x" value="-180"/>
<property name="y" value="-90"/>
<property name="width" value="360"/>
<property name="height" value="180"/>
</bean>
</property>
<property name="resolutions">
<list>
<value>0.5</value>
<value>0.25</value>
<value>0.125</value>
<value>0.0625</value>
<value>0.03125</value>
<value>0.015625</value>
<value>0.0078125</value>
<value>0.00390625</value>
<value>0.001953125</value>
<value>0.0009765625</value>
<value>0.00048828125</value>
<value>0.000244140625</value>
<value>0.000122070312</value>
</list>
</property>
<property name="dataSourceName" value="bluemarble" />
<property name="tileWidth" value="512"/>
<property name="tileHeight" value="512"/>
</bean>
<bean name="wmsBluemarble" class="org.geomajas.layer.wms.WmsLayer" >
<property name="layerInfo" ref="wmsBluemarbleInfo" />
<!-- When configuring your own applications, please do not use this WMS server -->
<property name="baseWmsUrl" value="http://apps.geomajas.org/geoserver/wms"/>
<property name="version" value="1.1.1"/>
<property name="format" value="image/jpeg"/>
<property name="styles" value=""/>
</bean>
Caution
The correct display of a WMS layer with respect to other
layers can only be assured if the CRS of the layer is the same as the CRS
of the map. If the CRS values differ, the effect may be
translation or distortion of the layer data when drawn on the
map. Change the CRS of the map if necessary.
The first property is the layer info object, which describes the
metadata common to all raster layers. Visit the Geomajas
developer guide to learn more about it. This guide will focus on
the WMS specific configuration options.
The most important parameter here, is the dataSourceName,
which must point to a layer name as specified by the WMS server. Note
that comma separated values are supported, as the layer name is
literally used in the WMS requests.
As you can see, the bean class refers to the actual layer type:
org.geomajas.layer.wms.WmsLayer. The layer object contains
some extra properties which are specifically tied to the WMS server.
Some of these are required, some are optional.
Table 2.1. WMS layer properties
Name Description
baseWmsUrl
(required)
The base url of the WMS server. This is the base part
(excluding the request parameters) of the url that would be
called to execute a WMS request.
version
(optional)
Version of the WMS protocol which should be used. Check
your server configuration for possible values. This defaults to
"1.1.1".
format
(optional)
The mime type in which the images should be returned, for
example "image/gif". Check your server configuration for
possible values. This defaults to "image/png".
styles
(optional)
Some WMS servers support multiple styles for their
layers. Check your server configuration for possible
values.
parameters
(optional)
You can define additional parameters which can be passed
to the WMS server for each GetMap request. These are name/value
pairs which are passed in
org.geomajas.configuration.Parameter objects. See
"Adding extra
parameters" for more information. authentication
(optional) Optional basic or digest HTTP authentication. This bean
is of the type:
org.geomajas.layer.common.proxy.LayerAuthentication.
When set, the WMS request is automatically proxied to assure
that credentials are not leaked to the client. See "Using authentication" for
more information. useProxy
(optional) Allows you to force the use of a proxy to get the image.
This can be useful if you want to hide the WMS URL (excluding
the parameters that is). This is automatically enabled when the
authentication property is set (to assure that credentials are
not visible on the user). useCache
(optional) Allows you to force caching of WMS tiles.This can be
useful if you want to unload the used WMS server. This
automatically enables the useProxy property to be able to cache
the images. enableFeatureInfoSupport
(optional) Setting this to true allows you to use the SearchByPoint
command to access the GetFeatureInfo capability of the WMS
server. featureInfoFormat
(optional) Set this if you want to change the featureInfoFormat when
feature info is enabled. Most wms servers support the default GML2 format,
but some servers only allow plain text or html. Possible values are:
GML2, GML3, HTML, TEXT and JSON. When set to something different than GML,
the feature returned to the client will contain one attribute with the
HTML or TEXT string.
In the previous paragraph, we mentioned the possibility to
configure extra parameters to be passed to the WMS server when executing
the GetMap requests. This option can be useful for example for
configuring the use of transparency.
Below is an example of a WMS layer configuration which uses
transparency:
<bean name="wms03" class="org.geomajas.layer.wms.WmsLayer" >
<property name="layerInfo" ref="wms03Info" />
<!-- When configuring your own applications, please do not use this WMS server -->
<property name="baseWmsUrl" value="http://apps.geomajas.org/geoserver/wms" />
<property name="version" value="1.1.1"/>
<property name="format" value="image/png;%20mode=24bit"/>
<property name="styles" value=""/>
<property name="parameters">
<list>
<bean class="org.geomajas.configuration.Parameter">
<property name="name" value="transparent" />
<property name="value" value="TRUE" />
</bean>
</list>
</property>
</bean>
The optional HTTP authentication allows the WMS layer to send user
credentials to the WMS server in the HTTP headers. Although this is an
option, often WMS server will be secured, and require such
authentication. Below is an example of a WMS layer configuration that
uses the HTTP authentication:
<bean name="wmsOrtho" class="be.geomajas.layer.wms.WmsLayer" >
<property name="layerInfo" ref="wmsOrthoInfo" />
<property name="baseWmsUrl" value="http://ogc.beta.agiv.be/ogc/wms/orthoklm" />
<property name="version" value="1.3.0" />
<property name="format" value="image/jpeg" />
<property name="styles" value="" />
<property name="authentication">
<bean class="be.geomajas.layer.common.proxy.LayerHttpAuthentication">
<property name="user" value="<the user name>" />
<property name="password" value="<password>" />
<property name="realm" value="<optional realm>" />
<property name="applicationUrl" value="<the URL for this web application>" />
</bean>
</property>
</bean>
Let us go over the properties for the authentication bean:
Table 2.2. WMS authentication properties
Name Description user
(required) The user login name. password
(required) The users password. realm
(optional) The HTTP realm for this user. This is an optional
value. authenticationMethod
(optional) Authentication method to use. Options are
LayerAuthenticationMethod.BASIC (default) and
LayerAuthenticationMethod.URL. userKey
(optional) Key which is used to pass the user name when using the
URL authentication type. passwordKey
(optional) Key which is used to set the password when using the URL
authentication type.
When using the optional Proxy setting you can provide extra
HttpRequest interceptors which will be used by the proxy to further
customise your requests (add extra parameters / headers for security or
do some logging). To add interceptors add a bean of type
LayerHttpServiceInterceptors to your spring configuration. This contains
a map of HttpRequestInterceptor lists. The key is the name of a layer or
the prefix to the baseUrl property of the RasterLayerInfo object.
To add an interceptor to all layers use an empty key (eg. ""). To
add an interceptor to a specific layer use the name of this
layer.
Sample bean configuration:
<bean name="interceptors" class="org.geomajas.layer.common.proxy.LayerHttpServiceInterceptors">
<property name="map">
<map>
<entry key="">
<list>
<bean class="org.geomajas.layer.wms.sample.AddSomeLeetHeadersHttpRequestInterceptor" />
</list>
</entry>
</map>
</property>
</bean>
Table of Contents
Usage examples for the WMS layer.
As an example, let's show some code which implements a click (or
mouse up) event which should read the feature information. It assumes the
map widget is known in the variable mapWidget. :
Example 3.1. Using the SearchByPoint command
public void onMouseUp(MouseUpEvent event) {
Coordinate worldPosition = getWorldPosition(event);
Point point = mapWidget.getMapModel().getGeometryFactory().createPoint(worldPosition);
final SearchByPointRequest rasterLayerRequest = new SearchByPointRequest();
rasterLayerRequest.setLocation(point.getCoordinate());
rasterLayerRequest.setCrs(mapWidget.getMapModel().getCrs());
rasterLayerRequest.setSearchType(SearchByPointRequest.SEARCH_FIRST_LAYER);
rasterLayerRequest.setPixelTolerance(pixelTolerance);
rasterLayerRequest.setLayerIds(getServerLayerIds(mapWidget.getMapModel()));
rasterLayerRequest.setBbox(toBbox(mapWidget.getMapModel().getMapView().getBounds()));
rasterLayerRequest.setScale(mapWidget.getMapModel().getMapView().getCurrentScale());
GwtCommand commandRequest = new GwtCommand(SearchByPointRequest.COMMAND);
commandRequest.setCommandRequest(rasterLayerRequest);
GwtCommandDispatcher.getInstance().execute(commandRequest,
new AbstractCommandCallback<SearchByPointResponse>() {
public void execute(SearchByPointResponse response) {
// ... process response
}
});
}
This is the default.
Pixel tolerance if known. Currently not used by the WMS
layer.
Here you can do what needs to be done with the
response.
Note that the features returned are not defined anywhere in the
configuration. The feature is filled with whatever data is
retrieved from the WMS server.