Thanks for all your replies! I followed the link to the Geoserver Blog posted by Sophia, trying the approach with arrows combined from dashed lines.
It's a bit hackish, but it does the job. Have a look here: http://hwellmann.blogspot.com/2009/04/arrows-with-styled-layer-descriptor.html Of course, I'm still interested in a more direct solution, in uDig or at SLD level, but for now, I'm quite happy with this approach. Cheers, Harald > -----Ursprüngliche Nachricht----- > Von: [email protected] > [mailto:[email protected]] Im Auftrag > von Jody Garnett > Gesendet: Dienstag, 7. April 2009 15:32 > An: User-friendly Desktop Internet GIS; Andrea Aime > Betreff: Re: [udig-devel] Arrowhead Symbolizers > > Right now SLD renders a point symbolizer half way along the > line I think. > > Andrea and I are just talking about how to do this; what we > need to do is "preprocess" the geometry prior to letting a > point symbolizer draw it. We are thinking of allowing the > point symbolizer to define a geometry expression (rather than > just a geometry); however there are some problems with this > approach (since it makes figuring out what bounding box to > request difficult) unless the function can be "inverted" or > something. The alternative is to strictly define the > available geometry preprocess options (first point; last > point; buffer; etc...). I would like to do better then this > in order to allow linear referencing system style drawing > (draw the line from 20% to 80% in this color). > > Cheers, > Jody > > On Tue, Apr 7, 2009 at 7:51 PM, Wellmann, Harald > <[email protected]> wrote: > > How to style line features with an arrowhead at either end? > Preferably > > using SLD, other methods are welcome if SLD does not support that. > > > > I found this thread on the subject: > > http://www.nabble.com/Directional-Symbology-td12231197.html > > > > ...but it does fully answer the question. > > > > Given a line feature type with a LineSymbolizer, if I define an > > additional PointSymbolizer for that type, where do the > point symbols > > get placed? At the first vertex, the last, somewhere in the > middle of > > the line? > > > > Do I have to create an additional point feature just to > position the > > arrow icon on a line feature? > > > > And of course it is not enough to place an arrowhead icon at the > > endpoint of a line, you want the arrowhead to be correctly oriented. > > > > I'm thinking of something like > > > > <sld:LineSymbolizer> > > <sld:Stroke> > > <sld:CssParameter name="arrow-direction"> > > <ogc:Literal>backward</ogc:Literal> > > </sld:CssParameter> > > <sld:CssParameter name="arrow-head"> > > <ogc:Literal>double</ogc:Literal> > > </sld:CssParameter> > > </sld:Stroke> > > </sld:LineSymbolizer> > > > > > > where > > > > arrow-direction = none|forward|backward|bothways > > > > arrow-head = simple|double|filled|... > > > > and maybe you want an additional tag for placing the arrows > either at > > the endpoint of the line or in the middle. > > > > > > Regards, > > > > Harald > > > > ******************************************* > > innovative systems GmbH Navigation-Multimedia > > Geschaeftsfuehrung: Edwin Summers - Michael Juergen Mauser Sitz der > > Gesellschaft: Hamburg - Registergericht: Hamburg HRB 59980 > > > > ******************************************* > > Diese E-Mail enthaelt vertrauliche und/oder rechtlich > geschuetzte Informationen. Wenn Sie nicht der richtige > Adressat sind oder diese E-Mail irrtuemlich erhalten haben, > informieren Sie bitte sofort den Absender und loeschen Sie > diese Mail. Das unerlaubte Kopieren sowie die unbefugte > Weitergabe dieser Mail ist nicht gestattet. > > This e-mail may contain confidential and/or privileged > information. If you are not the intended recipient (or have > received this e-mail in error) please notify the sender > immediately and delete this e-mail. Any unauthorized copying, > disclosure or distribution of the contents in this e-mail is > strictly forbidden. > > ******************************************* > > _______________________________________________ > > User-friendly Desktop Internet GIS (uDig) > http://udig.refractions.net > > http://lists.refractions.net/mailman/listinfo/udig-devel > > > _______________________________________________ > User-friendly Desktop Internet GIS (uDig) > http://udig.refractions.net > http://lists.refractions.net/mailman/listinfo/udig-devel > _______________________________________________ User-friendly Desktop Internet GIS (uDig) http://udig.refractions.net http://lists.refractions.net/mailman/listinfo/udig-devel
