OsmAnd: Why Offline Search is So Hard

You type an #address into a #map app on a phone in airplane mode. There is no server to ask: the phone has to find it on its own. Why is that so hard?

We walk the whole road we took to rebuild offline search in #OsmAnd: what an address really is, where we got real examples to measure search, why the old algorithm kept failing, and the new search that puts the words on the map.

https://www.youtube.com/watch?v=aScKKQvZx3U

Chapters

• 0:00 Intro: the data was there
• 1:24 Part 1 · Addresses: a language without rules
• 4:21 Part 2 · Dataset: where do we get examples?
• 6:40 Part 3 · The librarian algorithm
• 9:27 Part 4 · Words on the map
• 11:45 Part 4.1 · Tiles
• 13:31 Part 4.2 · The zipper
• 14:07 Part 4.3 · Skip-tile zipper
• 16:49 Part 5 · A puzzle of words
• 21:14 Part 6 · Where we are now and what's next

The new search comes with the upcoming OsmAnd 5.5, and you can try it today in our nightly builds. As always, the code is on GitHub: https://github.com/osmandapp/OsmAnd

When search can't find something, tell us what you typed: every miss becomes a test. And help the map: add street names and town boundaries in OpenStreetMap.

OsmAnd: https://osmand.net