[Users] How to create legend panel using OpenLayers.Layer.MapServer layer...

[Andreas Hocevar]

On 2010-01-06 18:34, stela anders wrote:
> Thanks again...
> I have 3 layers, each one has several sublayers.... :
> OpenLayers.Layer.WMS("Layer1", ...
> OpenLayers.Layer.WMS("Layer2",
> OpenLayers.Layer.WMS("Layer3",


GeoExt/OpenLayers does not know about your sublayers in this case.

> But my legend only prints one Label ("Layer1") .... None imagens at
> all... And just for the first layer...

And do you also just see "Layer1" on your map? If so, then probably all
your WMS layers are configured as base layers, only one of which can be
visible at a time. The legend should show all the layers that are
visible on the map, at least the labels with the layer names.

> Is there anything else to implement ? Maybe in mapfile?

I don't know much about MapServer, but I guess you have to configure
something in your mapfile so MapServer can return a legend graphic.
Search the MapServer documentation for GetLegendGraphic, as this is the
request that GeoExt sends to the server to get the images.

Regards,
Andreas.


>
> Stella
>
>
>
> 2010/1/6 Andreas Hocevar <ahocevar at opengeo.org
> <mailto:ahocevar at opengeo.org>>
>
>     On 2010-01-06 18:00, stela anders wrote:
>     > Yeah! Thats it Andreas!
>     >
>     > That LegendPanel works with sublayers? I´m a little bit confused
>     right
>     > now!
>
>     The LegendPanel currently supports one image per layer. GeoServer's
>     GetLegendGraphic e.g. returns images with symbols and text for all
>     rules
>     of the SLD that was used to render the layer. I think the same is true
>     for MapServer, but maybe a MapServer user can give more detail about
>     what its GetLegendGraphic returns.
>
>     Regards,
>     Andreas.
>
>
>     >
>     > Thanks !
>     >
>     >
>     >
>     > 2010/1/6 Andreas Hocevar <ahocevar at opengeo.org
>     <mailto:ahocevar at opengeo.org>
>     > <mailto:ahocevar at opengeo.org <mailto:ahocevar at opengeo.org>>>
>     >
>     >     Hi,
>     >
>     >     make sure that your Ext JS build contains Ext.form.Label, or
>     use a
>     >     full
>     >     build. The build that most of the GeoExt exmaples use
>     >     (http://extjs.cachefly.net/builds/ext-cdn-771.js) does not
>     contain it.
>     >     Look e.g. at
>     >     http://dev.geoext.org/trunk/geoext/examples/legendpanel.html, it
>     >     uses a
>     >     full build.
>     >
>     >     Regards,
>     >     Andreas.
>     >
>     >     On 2010-01-06 16:24, stela anders wrote:
>     >     > Thanks Andreas !!!!
>     >     > I changed to WMS with success...
>     >     > But now I got that error when trying to generate the legend :
>     >     >
>     >     > Error: Ext.form.Label is not a constructor
>     >     > Arquivo-fonte:
>     >     >
>     >    
>     http://localhost/Openlayer/Arquivos/geoextx/lib/GeoExt/widgets/LegendPanel.js
>     >     > Linha: 293
>     >     >
>     >     > Am I suppossed to change anything?
>     >     >
>     >     > Thanks
>     >     >
>     >     > Stella
>     >     >
>     >     > 2010/1/5 Andreas Hocevar <ahocevar at opengeo.org
>     <mailto:ahocevar at opengeo.org>
>     >     <mailto:ahocevar at opengeo.org <mailto:ahocevar at opengeo.org>>
>     >     > <mailto:ahocevar at opengeo.org <mailto:ahocevar at opengeo.org>
>     <mailto:ahocevar at opengeo.org <mailto:ahocevar at opengeo.org>>>>
>     >     >
>     >     >     Hi,
>     >     >
>     >     >     On 2010-01-04 19:36, stela anders wrote:
>     >     >     > Is it possible?
>     >     >
>     >     >     You have at least two choices:
>     >     >
>     >     >     (1) Use Layer.WMS instead of Layer.MapServer. With minor
>     >     modifications
>     >     >     to your mapfile, it is easy to use MapServer as WMS (see
>     >     >     http://mapserver.org/ogc/wms_server.html). I think this is
>     >     the best
>     >     >     option, because it will build the legend automatically
>     from
>     >     >     GetLegendGraphic requests.
>     >     >
>     >     >     (2) Use a LayerStore with a legendURL field. For each
>     layer, you
>     >     >     have to
>     >     >     provide a URL that points to a legend image. This
>     option may
>     >     only work
>     >     >     with the current trunk version of GeoExt, not with v0.6.
>     >     >
>     >     >     Regards,
>     >     >     Andreas.
>     >     >
>     >     >     >
>     >     >     > I tried to create that :
>     >     >     >   var legendPanel = new GeoExt.LegendPanel({
>     >     >     >             title: 'Legend',
>     >     >     >             dynamic: true
>     >     >     >      });
>     >     >     >
>     >     >     > And added to Viewport, but nothing is created...
>     >     >     >
>     >     >     > Help me please!
>     >     >     >
>     >     >     >
>     >     >     >
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>     >     >
>     >     >     --
>     >     >     Andreas Hocevar
>     >     >     OpenGeo - http://opengeo.org/
>     >     >     Expert service straight from the developers.
>     >     >
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>     >     --
>     >     Andreas Hocevar
>     >     OpenGeo - http://opengeo.org/
>     >     Expert service straight from the developers.
>     >
>     >
>
>
>     --
>     Andreas Hocevar
>     OpenGeo - http://opengeo.org/
>     Expert service straight from the developers.
>
>


-- 
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.