[OSM-dev] Porting the mapnik stylesheet to carto

[Matt Williams]

On 16 November 2012 16:50, Andy Allan <gravitystorm at gmail.com> wrote:
> Hi All,
>
> Matt has mentioned it in the other thread regarding the stylesheets,
> but I thought I'd expand a bit on what I'm up to.
>
> For a long time (coming up for a year now) I've been contemplating
> creating a carto version of the main stylesheets. I ported all my own
> stylesheets from xml to carto and found a renewed joy in developing
> them, both through the change in syntax and from the improved
> toolchain (i.e. using TileMill). Also, I much prefer using git than
> SVN, since it makes it much easier to try things out on a branch and
> seek feedback, rather than passing patch files around or just stomping
> over the main branch - or even having patches slip by because people
> (like me) are uneasy just committing them and never get round to it.
> Finally, I've seen so many thinly-customised versions of the OSM
> stylesheets that I know people are trying and struggling to work with
> them, and I have painful experience of working with multiple different
> XML stylesheets (OpenCycleMap and MapQuest, to name but two).
>
> I had no idea how few commits there had been to the stylesheets over
> the last six months (pretty much none, really), so there's a good
> opportunity for a conversion given the reasonably static target.
> Yesterday I decided that rather than emailing the list, I would dive
> in and see how much work it would be to convert them to carto, and
> whether it's feasible
>
> https://github.com/gravitystorm/openstreetmap-carto
>
> By a rough metric of number of mapnik rules, I'm 48% of the way
> through the conversion. Currently the map looks like this:
>
> http://thunderflames.org/temp/openstreetmap-carto-wip.png
>
> So far so good!
>
> I strongly believe that this is the way forward. Ideally I'd like to
> finish the conversion and hit a 1.0.0 release of the new stylesheets -
> one that we can swap yevaud over to without causing much kerfuffle.
> Then I've already identified a bunch of improvements to the stylesheet
> that will make life easier, and which I hope will attract new
> cartographers (the many who are familiar with Tilemill) and/or
> rekindle interest from our battle-hardened veterans.
>
> At the very least, we'll soon have a carto version of the current
> stylesheet. Regardless of what we decide wrt to old XML stylesheets -
> if, say, someone else decides to take them on and develop them in the
> traditional manner - I'm sure the carto version will be of interest to
> many people.
>
> Please, ask away if you have any questions. I'll keep the list posted
> with how I get on.

Great work. Do you have any idea how/if the performance changes when
using Carto rather than the old XML?

Matt