New design for locations

[gcampax]

Representing locations as a single pair of coordinates is insufficient, because it does not account for the extents of the location, which can be a building, a street, a city, an administrative division (county, state, province...) etc.

I propose we represent locations as:

• a name
• a specific point on Earth
• a radius around that point, based on the type of location (building, street, city)
• a hierarchy of administrative divisions (starting at county/parish for the US) that entirely contain the location.

For example, "Palo Alto" would be:

• 37.442156, -122.1634471
• 10km radius (city)
• Santa Clara County, California, United States

"University Ave" would be:

• 37.4466552,-122.1626787
• 500m radius (street)
• Santa Clara County, California, United States

"353 Jane Stanford Way Stanford California" would be:

• 37.4299908,-122.175519
• 100m radius (building)
• Santa Clara County, California, United States

"my current location" (assuming I'm at Gates) would be:

• 37.4299908,-122.175519
• 1m radius (GPS)
• Santa Clara County, California, United States

Two locations are ==-equal if the intersect. This should give the right semantics for location filters.

[gcampax]

We should also include the timezone information in each location, so we can display times correctly for that location (for weather, opening hours, etc.)