[Tilecache] metabuffer results in conflicting behavior for point & line labels..

[Christopher Schmidt]

On Fri, Oct 12, 2007 at 03:48:08PM +0530, louvy.joseph at gmail.com wrote:
> I am using tilecache metaSize of 3,3 and I have both lines & points in 
> my geoserver-1.5.3 based wms server.
> 
> When I have metaBuffer=0, some of my text labels for the points get 
> dropped. I am thinking that these points happen to be at edges of meta 
> tiles and there is not enough space to render the label and so the 
> geoserver drops them.
> 
> Now if I start increasing the metaBuffer to 10, 20 or 30 pixels, now 
> slowly more of my points start showing up. But my line names are getting 
> chopped now. I tried various metaBuffer options but I am not able to 
> correct the problem of line names getting chopped.

> Does anybody have any ideas? Am I doing something wrong? Is this tunable 
> in tilecache or geoserver SLD or where else?

In MapServer, there is a "labelcache_edge_buffer" option that allows you
to control the space along the edge of the tiles that is *not* filled
with labels. I don't know if there is something similar in GeoServer or
not. (Mapnik uses geographic placement for lines/polys, so it doesn't
have this problem either.) 

Regards,
-- 
Christopher Schmidt
MetaCarta