[OSM-dev] Converting OSM Mapnik stylesheet to Cascadenik or Carto

[Andy Allan]

On Wed, Jul 27, 2011 at 4:03 PM, Phil! Gold <phil_g at pobox.com> wrote:
> * Josh Doe <josh at joshdoe.com> [2011-07-27 10:52 -0400]:
>> I'm curious if anyone has ever attempted to convert the massive OSM Mapnik
>> stylesheet to one of the CSS-like languages such as Cascadenik or Carto.
>
> I started trying to do a conversion to Cascadenik, but gave up on it because
> Cascadenik was generating tons of unnecessary rules (basically, the cartesian
> product of all my selectors) that slowed Mapnik down quite considerably.
> Maybe it's possible, but it's certainly not for the faint of heart.

There's a new feature in mapnik to handle this better which carto uses
- a flag for mapnik to match only one rule per style. Saves all the
"and not X and not (not X and Y)" that Cascadenik generated. I don't
know how much it helps though, all my projects have either been XML or
cascadenik, or carto, and I've never tried converting one to the other
and comparing benchmarks.

Cheers,
Andy