As a proof-of-concept for the rendering of labels on demand I set up an OpenLayers map with two XYZ tile layers, one for the background and one for the labels. I configured the MapQuest render stack to deliver those two layers, the background layer is stored in the tile store, the label layer is never stored, but always rendered on demand.

Nearly everybody setting up an OSM tile server uses either the Apache/mod_tile/renderd or the Apache/mod_tile/Tirex combination. The renderd software has been around for while. When we needed something more flexible two years ago, Frederik Ramm and I created Tirex. To keep the development work needed small and make it easier to switch from renderd, Tirex uses the same Apache/mod_tile frontend as renderd. We had plans to add different frontends, but they never materialized. Apache/mod_tile is difficult to configure and not very flexible, but it does its job well enough. I wrote a proof-of-concept frontend using node.js, but that was never taken up either.

In Choosing a Language I have proposed to think about how to render labels in different languages into the tiles on the fly when they are requested.

One key issue of the multilingual map project is obviously how we choose which language labels to render into a map. There are two sides to consider:

(This article is a (modified) translation of a German language article I wrote for the German OpenStreetMap blog. It should have been translated months ago, but I am only now getting around to it. The project was a bit slow in starting but is gathering momentum now. It has progressed a bit since the original article.)