[OSM-talk] buildings

Dave Stubbs osm.list at randomjunk.co.uk
Wed Jul 25 12:08:24 BST 2007


On 25/07/07, Cameron Patrick <cameron at patrick.wattle.id.au> wrote:
> Dave Stubbs wrote:
>
> > > Nah, that should be easy to fix by editing the Mapnik XML.  It's not
> > > that scary, honest!
> >
> > Hey! Who was scared?! :-)
>
> Hehe. I was when I first started poking it :-)
>
> > It may not be scary, but it is completely undocumented. Unless there
> > is some hidden documentation somewhere.
>
> That's true, as far as I can tell.
>
> > So how would you fix the XML? Botch the SQL, or is there some weird
> > and wonderful symbolizer incantation?
>
> The railway field is already being put into the database and pulled out
> again by mapnik.  It should be a matter of adding a symbolizer
> incantation - I'd probably copy/paste/adapt from the one for school and
> change the colouring.  (These are in the <Style name="leisure"> block
> for no good reason that I can see!)
>
> Cameron (Disclaimer: I only started fiddling with Mapnik last night so I
> may be leading you up the garden path here!)
>

Yeah, the problem here is that the SQL in the datasource section grabs
rows from the polygon table to plot all the areas. The railway feature
isn't being imported into the polygon table though, because in
general, ways defined with the railway key are imported to the lines
table. So to fix it there are 3 options as I see it:
 1) add building=station to all railway stations
 2) alter the import script
 3) play with the SQL in the render script (not sure this would work)

for the moment I've done (1) :-)




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