Turn on geocoding without turning it into a project
You need to turn an address into a coordinate. That's the whole ask. The problem is that the two ways to get there both start as a project.
18 posts tagged with "Geocoding"
Turning parsed addresses into coordinates — cascades, precision tiers, and the reference datasets behind them.
View All TagsWe almost retrained a model to fix a stale symlink
Mailwoman couldn't find Tirana, or Yerevan, or 145 other capitals — not a wrong coordinate, silence. We were going to fix the parser. A ten-minute probe killed that plan, and a stale symlink nearly talked us into a GPU retrain to fix a model that was already fine. Two evals, two silent confounds, and the one dull habit that caught both.
We made Mailwoman speak Nominatim, and it put Warsaw in Indiana
You can point a Nominatim client at Mailwoman now and get a geocoder from a SQLite file, without PostgreSQL or a planet import. We did, and the US worked beautifully while the rest of the world resolved to its American namesake. The bug was one line: we'd told it the answer was always America. This post covers the line, the four cities that still won't move once you delete it, and the ranking database we forgot to switch on — which faked the entire scoreboard until a contradiction gave it away.
A confidence you can route on
You've got a hundred thousand addresses to reconcile. Two databases, the same clinics and providers scattered across both, each one spelled a dozen ways none.
We lost to Nominatim in Europe. Then we found out why.
We ran our 30 MB browser geocoder against the incumbents — Nominatim and Pelias — on real European addresses, scored the direct way. We'd won the US. Europe opened with a double-digit loss. The cause was silence: on messy addresses we returned no result at all. This post covers what caused the empty results, the three fixes that took us clear of both incumbents in Europe, and the one place — Australia — we've now diagnosed but not yet closed.
Right on the map, wrong on the test
Our parser scores 28% on Spanish addresses by the metric that grades its labels. By the metric that grades where the address lands on Earth, it's within a couple of kilometers. Same model, same addresses. Only one of those numbers is measuring the thing we ship.
We shipped 'world coverage.' It covered 97 countries.
Open the demo and type an address in Kabul, and the demo returns no result. It does not place a pin a few streets off or fall back to the city center, because the gazetteer has no entry for Kabul. Hong Kong, Tirana, Chişinău, and every place in the Democratic Republic of the Congo return no result as well. We had been calling this gazetteer "world coverage" for weeks, and it covered 97 of the world's ~195 countries. The other ninety-odd countries were absent from the file.
243 round trips to find a city
The whole geocoder runs in your browser. You type an address, you get a rooftop coordinate, and no server ever sees your query — the gazetteer it resolves against is a SQLite database sitting on a CDN, and the page reads it with HTTP range requests, a few kilobytes at a time. It's a lovely trick. We were proud of it. Then we counted the requests it took to find a single city, and the number was 243.
843,000 postcodes and no Canada
Overnight I taught the geocoder Canada. Or I thought I did. I pulled 843,000 Canadian postcodes, computed a centroid for every one, spot-checked the result — M5H 2N2, downtown Toronto, 43.652, −79.382, dead on — and validated the database every way I could read it: every postcode present, every coordinate right, and no other data disturbed. Green, top to bottom. This morning, before flipping it live, I asked the demo to find a Toronto address. It dropped the pin in Ohio.
Geocoding that never phones home
Open the demo, open your browser's network tab, and type an address. It resolves to a rooftop coordinate: 1600 Pennsylvania Ave lands on the actual building, within about ten meters. The network tab shows no request carrying your address. The parser ran in the page. The gazetteer it resolved against is a file on a CDN, and the page read it a few kilobytes at a time. The query stayed on your machine.