[OpenLayers-Dev] Show the direction of a link

Tim Schaub tschaub at opengeo.org
Fri Jan 23 14:26:06 EST 2009


Niklas Ringdahl wrote:
> Hello.
> I want to show the direction of links/vectors in a WFS or WMS layer, to be
> able let the user set a "one way street"-property of road data to be "in
> link direction" or "against link direction". I am visualizing some sort of
> arrow on the road or maybe a symbol at the first node of the vector. Is it
> possible to do this with SLD? Or does anyone have any other suggestion in
> how to display this property?

The only way I can think of doing this immediately is to have features 
with point geometries and a direction attribute.  The points could be 
symbolized with an arrow graphic where the symbolizer rotation was 
determined by the direction attribute (degrees clockwise from 
orientation of graphic).

     externalGraphic: "arrow.png",
     pointRadius: 10,
     rotation: "${direction}"

Of course, your data probably doesn't come with these points/attributes. 
  But, you could generate them client side.


> Thanks in advance.
> - Niklas

Tim Schaub
OpenGeo - http://opengeo.org
Expert service straight from the developers.

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