[OSM-dev] Obtain SLD style for osm

Jukka Rahkonen jukka.rahkonen at mmmtike.fi
Thu Jan 28 09:59:03 GMT 2010


Dane Springmeyer <blake <at> hailmail.net> writes:

> On Jan 26, 2010, at 8:05 AM, moataz Elmasry wrote:
> 
> > Hallo list
> >
> > 1- We are developing a GIS application using osm maps and a geoserver.
> > My problem is that there's no reliable sld style for the osm maps.
> 
> Right, because it takes a serious amount of effort, care, and  
> commitment to create and maintain styles as sophisticated as those  
> behind many of the well know maps from OSM that use Mapnik.

For sure making as fine tuned styles than Mapnik osm.xml takes enourmous amount
of work, several months I would guess.  However, it may be possible to start
from more simple styling first.
 
> > Although the assignment states that we use geoserver as our wms map
> > server and maps from osm, but I feel that its not a very smart idea to
> > mix the two, what do you think?
> 
> Mixing WMS and OSM data in general when using complex styles is  
> usually not the right approach, no matter what library you use to do  
> the rendering because the size of the data and time it takes to render  
> the styles is much better done using TMS (Tiled Map Service). This is  
> the way that tile.openstreetmap.org works (using mod_tile), serving  
> tiles that get cached for speed once they are rendered.
> 
> I would recommend using the existing OSM styles + Mapnik + mod_tile.

Think about what the users will do with the application.  Tiles are fast but
dull, they are effective only if all the users are satisfied with the same
rendering. There is some possibilities to tailor the result by making simple
enough tiled base layer and let users to select which overlays will be drawn on
top. But some basical changes affecting tile rendering, like selecting the
language of place names, or map projection, or selecting which features will be
rendered on a map that will easily lead to a need to have many tilesets.  At
some point rendering everyting on-the-fly can become more suitable.

Have a look at http://osm.omniscale.de/ There is a possibility to compare the
speed of TMS and pure WMS.  WMS does not need to be awfully slow.  However, I do
not know what Omniscale is doing for accelerating pure non-tiled WMS.
WMS GIS clients let the users select the layers they want to see and it may be a
nice feature as well.

This is not a comprison between Mapnik-others, Mapnik can do on-the-fly as well
with OGCserver mode.

-Jukka Rahkonen-







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