[Mapnik-users] dirtying adjacent tiles

[Aryeh Leib Taurog]

Hello,

Given a set of coordinates for new or deleted features, I would like 
to determine which tiles to update.  All the feature are represented 
using PointSymbolizer.

Does the mapnik API provide an easy way to get the maximum 
PointSymbolizer icon size for a given zoom, so I can determine myself 
whether or not the icon will run off the edge onto the next tile?  Is 
there an easier way to do this?

At worst, I could just parse the xml mapfile and find the data, but if 
mapnik already parsed it once, I would like to think the information 
might be more easily accessible through mapnik.

thanks,
Aryeh Leib Taurog