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.
666,000 addresses and not one country
I taught the address parser three new countries overnight. Two of them landed. The third failed a regression check I trusted, and the reason was concerning: the new addresses never included their own country, and the model was learning to stop labeling countries at all.
We asked our address parser what it couldn't read
Most sequence labelers throw away the parts of an address they don't understand, and the output format is built to hide it. We made ours hand every dropped character back, then aggregated them into a ranked list. The top of the list turned out to be the Polish alphabet.
The model knew it was Austria. The resolver sent it to West Virginia.
Type 'Vienna, Austria' into our geocoder and it confidently returned a town of ten thousand people in Appalachia. The obvious fix was a retrain. We ran the diagnostic first, and the obvious fix turned out to be the wrong one.
We 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.