How I made the map of the buildings of Reykjavík

Every dataset is messy, and each is messy in its own way

We don’t live in a perfect world full of perfect things, but we can try to. Data fits this model: it’s never flawless, but we constantly strive to make it better.

The underlying data that makes up my map of Reykjavík’s buildings by contruction date comes from three sources: shapes and names of buildings are provided by OpenStreetMap; locations of land plots come from Þjoðskrá’s Staðfangaskrá dataset; and building construction dates come from Þjóðskrá’s Fasteignaskrá.

Combining datasets is always problematic as they’re often created in isolation without interoperability being a priority. You might see such problems hiding in the data sources above: OpenStreetMap has building shapes but no addresses, Þjóðskrá has one dataset with x and y coordinates for land plots but not buildings, and another with construction dates for properties (apartments etc) but not buildings. Joining these up is complicated.

A screenshot of part of the map being edited in QGIS
The map in a more raw form, before it was beautified.

While the vast majority of data on the map is accurate some errors have inevitably sneaked in. If you see an error in the names or building shapes, correct them on OpenStreetMap. And if you have a moment, ask Þjóðskrá to provide all building metadata as open data. Þjóðskrá have locations, construction dates, property values, and much more for every single free-standing building, apartment, and bike shed in Iceland; wouldn’t it be wonderful if that was open source?

I can also make corrections to the map directly. If you see anything you think is wrong, please contact me. If it’s a genuine error I’ll make a correction and note it here.

Contributed corrections

Weepy acceptance speech

Thanks to Þorlákur Lúðvíksson for help with the design process and Páll Hilmarsson for pointing me towards the data.