Accelerating Vector Tile Creation

Late summer brings a couple of interesting dates for the Marble community: On the Desktop we’ll release Marble 2.0 and around the same time our Android app Marble Maps will have its first stable release. Later on in September it’s time to celebrate the 10th birthday of the Marble project!

The common theme to the upcoming release is the introduction of the Vector OSM map: A beautifully styled map based on data from the OpenStreetMap project that spans the entire world from globe to street zoom level. In order to make this possible we’re working very hard behind the scenes to optimize both the tile data and the rendering in Marble to give you a smooth experience.

This weekend brought some good news for the tile data generation: The awesome KDE sysadmins (thanks, Ben!) setup a beefy server for us which is now busy generating vector tiles for larger areas. Together with a second server that has plenty of space to host data we now have great infrastructure to scale Vector OSM.

The tool chain running on the tile-builder server is subject to continuous improvements over the next weeks in order to optimize the tile generation process: On the one hand tiles need to be generated as fast as possible (to allow us updating them with fresh OSM edits regularly), on the other hand the generated data needs to be filtered, simplified and optimized (to reduce processing time during rendering).

The alpha version of Marble Maps integrates the Vector OSM map theme already. OSM bitmap tiles are activated by default though, so you have to enable vector rendering explicitly. This choice was made deliberately because the rendering performance in intermediate zoom levels is still far from what we want it to be. We hope to be able to resolve that in the next two weeks.

Keeping that in mind, once Vector OSM is activated you’ll notice that low zoom levels (where you see the entire globe) are already completely covered by vector tiles thanks to our GSoC student Akshat. Street level is available for selected cities and, thanks to tile-builder, is expanding to country level now. Germany and California will be the first to finish soon.