[OSM-talk] rendering with mapnik, what do I need?

[Andy Allan]

On Fri, Feb 22, 2008 at 2:18 PM, Dave Stubbs <osm.list at randomjunk.co.uk> wrote:
> On Fri, Feb 22, 2008 at 1:50 PM, Jo <ml at winfix.it> wrote:
>  > Do the transparent layers take the same amount of time to render as the
>  >  base layer for a given area?
>  >
>
>
>  This will depend entirely on what you put on them, and how you
>  organise that data in the database.
>  Assuming your transparent layer only has a few lines (ie: bus routes)
>  and you keep this data in a separate table, then they'll render
>  faster, probably a lot faster.

...than normal background tiles. I don't think Dave meant to imply
that it's quicker to render "background tiles" + "overlay tiles" than
it is to render one set of "background + overlay" tiles. Or in other
words, every line that gets drawn takes a certain amount of time. It
doesn't matter what the background colour is.

If you only want to draw some overlays for the standard OSM tiles then
you're quicker just drawing the overlays.

Cheers,
Andy