[OSM-talk] High Cartographic Quality Label Placement on OSM-based Map

Christoph Hormann chris_hormann at gmx.de
Sat Jul 13 18:36:40 UTC 2013

On Friday 12 July 2013, Maxim Rylov wrote:
> As far as I know Mapnik and other open-source software take into
> account only the rules R1, R2 and R5 (partially, returns labels that
> are evenly spread out, example - http://maps.skobbler.com/on z11).
> And the "greedy" algorithm that is utilized to solve the label
> placement problem returns rather poor approximation to the optimum as
> there is no backtracking.

I see - Mapnik labeling is well known to be quite bad so it is not 
really a good competition.  But you have not said which of these rules 
are followed by your method.  There seems to be an (only partially 
successful) attempt in R3 and R4 but R8 does not seem to play a role.  
R1 in several cases seems to work better in Mapnik. 

> > Is the algorithm available as open source?
> Unfortunately, the algorithm currently is not open-source, but the
> model that we elaborated and used will be published as a journal
> paper within the next few months.

Well - Peter has already commented on this and i mostly agree with him.

But i would actually emphasize a more practical point: Since this is 
meant to be scientific research one can assume you publish it to allow 
others to independently verify your work, compare it to their own and 
possibly improve it - this is in the very definition of scientific 
work.  When dealing with fairly complex algorithms like here this is 
next to impossible to do without publishing the code.

Now i understand you might be reluctant to make available the code 
before a journal publication and you would not necessarily need to make 
it open source/free software license wise although this would be 
advisable as a matter of fairness when extensively using Openstreetmap 

And i won't even get started on the fact that work of a publicly funded 
research institution should benefit the public...


Christoph Hormann

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