In one of my SotM 2011 talks, I suggested that OSM should have regular extracts of metropolitan areas for major world cities and their surrounding areas, regardless of state or country. This is a repository for a bit of code to make that real. I’ve decided to use Amazon S3 to host files, and EC2 to do the extracting. extract.sh is a script that performs the actual work with Osmosis and terminates its host machine upon completion.

Extractotron is run a few times per month, to http://metro.teczno.com. If you have cities to add, you can add them directly to cities.txt and send me a pull request in Github.

cities.txt is a tab-delimited file, and has eight fields:

• group

  One of "Africa", "Asia", "Europe", "Middle East", "North America", "South America", or Oceania.

• geonameid

  It's nice to have a link back to the Geonames dataset.

• top, left, bottom, right

  Geographic bounding box of the metropolitan area. These should be larger rather than smaller to surrounding countryside wherever possible. For example of coverage area, see Moscow.

• slug

  Short, lowercase version of the name with dashes for spaces that's used for files.

• name

  Full name of the city.

To use Extractotron yourself, use run-instance.py:

python run-instance.py <your AWS access key> <your AWS secret> <your bucket name>

By default, run-instance.py instantiates an m1.large instance with Alestic's Ubuntu 11.04 Natty instance-store AMI ami-68ad5201. You can change the instance type or AMI, see python run-instance.py --help for details.

Currently, the cities list is very short. Help me expand it by modifying cities.txt and sending a pull request via Github.