The OpenStreetMap community has assembled an enourmous database of our world. There are lots of more or less specialized maps out there, each showing some of the data. But there is no map that shows all of the data. How can we discover what is not shown by any map?

This talk is about a new Open Source web tool called OSM Spyglass that is trying to push the boundaries of what's possible with todays tools. It shows all the data that's currently in OSM. All nodes, ways, and relations planetwide, with their tags, with up-to-the-minute data, and some limited filtering options. Spyglass is a bit like the data overlay on openstreetmap.org on steroids.

I'll talk about how the tool came about, what it can do (and where its limits are) and how it works internally to process and present the OSM data. In the process we'll learn something about OSM data, about data processing with a modern osm2pgsql and PostgreSQL/PostGIS, and how to combine web mapping technologies from raster to vector tiles to GeoJSON into a seemless experience.