[OSM-dev] Announcing openstreetmap-carto v1.0 (and v2.0!)

Andy Allan gravitystorm at gmail.com
Tue Dec 4 12:43:48 GMT 2012

Hi all,

openstreetmap-carto is a project to re-implement the standard
OpenStreetMap mapnik style, in CartoCSS[1]. At the OpenStreetMap Hack
Weekend in London last Sunday I released v1.0 of project, and went to
the pub before telling anyone!

Version 1.0 is the complete re-implementation of the entire style in
CartoCSS, including all the features of the original layer. It is
pretty much pixel-for-pixel identical to the original style, with only
a couple of noticeable differences around vertical text spacing and
stacking of overlapping landcover polygons. I've spent a long time
comparing the output with that of the current mapnik stylesheets and
tracking down mistakes in the conversion, which you can see in the
run-up to the release. There might be some more mistakes that are
found later, in which case I'll release more versions in the v1.x

It's been a huge amount of effort, but it's entirely worth it to see
it all working in TileMill! Playing around with the style is now much
easier, and much more fun.

As per the roadmap, the next stage is to simplify the stylesheets to
make them "easier to wrangle". I've already started this, with
converting a couple of key colours into variables (so now you can
change the colour of all the water features with a one-liner) and
refactoring the style rules to make compilation times much faster (and
the output XML around 23% of the size of v1.0). So today marks the
release of v2.0, the first release of the refactoring work.

I intend to continue work on the refactoring, and I've started make
notes (in the form of github issues) to give you an idea of what the
upcoming work is likely to involve. I want to be cautious about making
the stylesheet "too clever", so if you've got an ideas for major
refactoring, lets discuss them!

If you have any questions, or if you have any successes or problems
trying to use the stylesheets, let me know!


[1] https://github.com/gravitystorm/openstreetmap-carto

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