Roll-your-own geocoding with OpenStreetMap Nominatim on Amazon EC2

Sometimes you need to geocode a few addresses, and while Google is obviously the gold standard, the Google Maps API conditions are quite strict – you are supposed only to geocode addresses you will be displaying in conjunction with a Google map. That’s no use for bulk / backend geocoding, the kind you might do for analysis purposes.


Google maps new !-style embed format

A while ago Google changed the structure of embedded map URLs. The old format used the web-standard key1=value1&key=value2 style, and you can find a reasonably good description of these parameters here. Unfortunately the new style is less verbose and much less intelligible, which seems like a step backwards even if these links are mostly hidden under the surface. Either Google wanted them to be less human-readable, or they care enough about saving a few bytes here and there to do this. I can’t find any good explanation of how to parse these links, so here’s my morning’s attempt. Be warned that this is all guesswork based on a limited sample and some experimentation. (more…)

UK Ethnicity Dot Map

London ethnicity dot map

« Take me back to the map! »

Frequently Asked Questions

What am I looking at?

Every person counted in the 2011 census of England, Wales and Northern Ireland is represented as a dot on this map – all 57,886,775 of them. Each dot’s location is near to a person’s usual residence, but the locations are not exact; public census results only report location to within a small area, usually containing a few hundred people. These are called ‘output areas’ in England and Wales, and ‘small areas’ in Northern Ireland. To create the map, I randomly place each person within their respective area. The colour of the dot reflects the person’s ethnicity as reported on the census.

Can I use this map?

Yes, with attribution. Consider it CC BY 3.0 licensed. The data is from the 2011 Census, via ONS (England & Wales) and NISRA (Northern Ireland) and you should cite them too, as the original source of the data.