I am currently trying to set up a Mapping-Service for serving OSM-Mapnik Tiles. In my project we want to use the Mapnik-Layer as a BaseLayer for our GI-Application. I am quite new to Mapnik (only used a public Mapnik-Service as a BaseLayer in OL so far) and i am now struggling with the decision about a good service architecture for my use case. Maybe somebody could give me a hint.
Currently from my point of view i have to decide between two possible service architectures:
1.) In the first solution i serve mapnik tiles via mod_tile. The OSM data lies in a PostGIS database and is updated regularly. Mod_tile in combination with rendered does than the rendering and tiling of the OSM data and serves the tiles via tileserver interface. This data could than be integrated in an OL-Application via OpenLayer.Layer.OSM.
2.) In the second possible service architecture the OSM data again lies in a PostGIS database and is updated regularly. But the data is now served via a wms interface (are there any good solutions for this?). The wms interface would then be cached by a separate mapping cache. After that the maps could be used in the OL-Application via wms or wmts interface.
From my initial point of view, the second solution would better fit in my existent architecture, where i already use a mapserver which is cached by a mapcache. Also if using wms and osm layers together in Openlayers, i always get some troublesome behavior of the map extent, where the mapnik tileset define the map extent. The problem is here, that the mapnik map extent is always quite bigger than the actual visible map extent. This also speaks for a wms / cache solution, where the behavior is from my point of view a bit more like i expect it.
On the other hand i am new to the mapnik world and so i am not sure if this solution does better fit to the osm data and idea. So what is your opinion and experience? What is are benefits of the first architecture compared to the second one? What are good software tools (in a debian environment) for publishing osm / mapnik data via wms interface?
I hope i make my point clear and some people could share there experience with me.
Best Answer
So basically you refer if a WMS or TMS is a better interface for your OSM map service?
Usually the TileMapService is the standard solution for OSM, as it fits better to the needs of usual endusers (parallel loading, fast displaying, ...). See also http://www.switch2osm.org This solution offers you also the most experience+tools from the osm community: http://help.osm.org
A WMS might be suitable for usual GIS-users, if they don't explore the map, but need it to work with certain areas in their workflow. There are several servers that you can use as rendering/server frontent http://wiki.openstreetmap.org/wiki/WMS#Server_Software
All in all, it depends on your usecase (behaviour of clients, map update-cycles, offered map coverage, ...) if a WMS or TMS is a better solution. Personally I would recommend a TMS because of better existing toolchain and maybe reproject it as WMS using http://wiki.openstreetmap.org/wiki/MapProxy