[OSM-dev] Mapnik output resolution

Graham Jones grahamjones139 at googlemail.com
Mon Feb 8 21:20:14 GMT 2010

Thanks Dane,
I'll go and sort out a 300dpi style sheet for my printed output, and add
some info to your trac ticket.


On 8 February 2010 04:21, Dane Springmeyer <blake at hailmail.net> wrote:

> On Feb 6, 2010, at 11:48 AM, Graham Jones wrote:
> Hi,
> My apologies - this is probably more of a Mapnik question than an OSM one,
> but I am using the OSM stylesheet, so I hope someone knows the answer!
> I am working on a little application to generate PDF map output with points
> of interest highlighted (ie to produce a 'restaurant guide' or 'tourist
> attractions guide' for an area) (http://www.townguide.webhop.net).
> If I select my map size to give 100 dpi resolution, the text size looks ok,
> but the output is a bit fuzzy (because it is only 100dpi).  If I increase
> the resolution to 300dpi by increasing the number of pixels I tell mapnik to
> use the text size reduces (or maybe it stays the same in pixels, but is
> smaller because I am printing at higher resolution) and it is no easier to
> read - it looks like mapnik uses a different zoom level because extra detail
> appears that I do not really want.
> For examples please see
> http://www.townguide.webhop.net/output/73/townguide_poster.pdf and
> http://townguide.webhop.net/output/72/townguide_poster.pdf for the 100 and
> 300 dpi versions respectively.
> Is there a way to tell mapnik what output resolution I want so that the
> font sizes, road widths etc. come out correct at different resolutions,
> Coming soon (likely will land by the next minor release - Mapnik 0.8.0):
> http://trac.mapnik.org/ticket/343
> or will I have to re-process the style sheet for different resolutions?.
> Yes, thats the recommended workaround for now. Holger (
> http://www.ancalime.de/) had a ruby script to do this that might be
> useful.
>  Any pointers would be appreciated please!
> It would be great if you would attach sample images, with the bbox used to
> generate them, along with any comments to that ticket. Once it rises to a
> high enough priority to revise work on... the more examples for testing the
> better.
> Dane

Dr. Graham Jones
Hartlepool, UK
email: grahamjones139 at gmail.com
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