6 ms·

As a sidenote, Australia moves about 7cm north annually [1], so any encoding of GPS location is not flexible enough in the long term. Also only encoding lat/lo

• clarkmoody 10y ago
  Given the spatial resolution of this project (10m) and the lifetime of humans (80 years), it should be alright :-) Floor / apartment number / suite number could just be tacked onto the end.
  • robalfonso 10y ago
    Any position can be determined from x,y,z, you could just tack on the z coordinate - though you'd need to match that locally, accounting for sea level. If you are using latitude and longitude you should stick with the paradigm for height, since floors can be different heights.
    • roywiggins 10y ago
      But then knowing something is X feet in the air only gives me an approximate floor number- I'd have to guess at the storey height and divide.
      • robalfonso 10y ago
        No question, I considered that too. But for determining position in 3d space I think its more consistent than having floors. If you get to say the 10th floor with different floor heights the difference could be considerable. Its the problem with whats practicable in daily use and what makes sense from a system perspective.
• rusanu 10y ago
  Obviously we need to add the date the coordinates were encoded. The decoding will have to apply correction based on ample databases of tectonic data. A simple formula will not work, a major earthquake can move a rift by some 5-10 cm. And you need to know exactly what plate does the coordinate refer to, is not as simple as 'Australia moves 7cm a year', consider parts of California east vs. west of the fault. Well, that spiraled out of control fast... It makes the time issues like [0] seem trivial by comparison. [0] http://stackoverflow.com/questions/6841333/why-is-subtracting-these-two-times-in-1927-giving-a-strange-result http://stackoverflow.com/questions/6841333/why-is-subtractin...
  • koolba 10y ago
    > Obviously we need to add the date the coordinates were encoded. The decoding will have to apply correction based on ample databases of tectonic data. A simple formula will not work, a major earthquake can move a rift by some 5-10 cm. And you need to know exactly what plate does the coordinate refer to, is not as simple as 'Australia moves 7cm a year', consider parts of California east vs. west of the fault. Well, that spiraled out of control fast... It makes the time issues like [0] seem trivial by comparison. I didn't think it was possible to come up with an idea worse than leap seconds but we did it guys!
    • cyphar 10y ago
      > I didn't think it was possible to come up with an idea worse than leap seconds but we did it guys! Leap seconds aren't the problem, its the fact that we're stuck on a Babylonian style of timekeeping. Measuring time with completely uncorrelated rotations of objects is a ... fun idea. Or maybe the problem is that time is very hard to determine "naturally".
      • roywiggins 10y ago
        Time is very easy to define naturally as long as it's always "local." Local noon is when the sun is at its highest. Local midnight is halfway between noons, come up with some subdivision, and you're done. It breaks down once you need to synchronize distant events of course...
• tener 10y ago
  Perhaps the address can be made relative to some landmark which moves in the same direction. This could add an additional word in front of it (for the landmark) but will resolve such issues.
  • aw3c2 10y ago
    That's a great idea, maybe something like "church street" and a number that denotes a length on that street?
    • dvcc 10y ago
      If that was the case we might run into naming collisions if there are multiple cities with the same street names. It would be best if we namespace it to the city as well. So we would have something like { "street": "Church Street", "length": "5", "city": "Church City" } all of course packaged in JSON.
      • aw3c2 10y ago
        That's a great idea and will help making addresses more solid. I would suggest we also add some more levels like the country the city is in?
        • dvcc 10y ago
          Wonderful idea, and we could even go so far as standardizing how we write it so that we don't need to worry about putting it into JSON and makes it more memorable for humans. Something like: Length Street City Country
          • camiller 10y ago
            To the extent that a single address might be home to more than one person, shouldn't we pre-pend the name of the specified person to the address?
        • frogpelt 10y ago
• jaakl 10y ago
  This problem could be resolved within coordinate systems adaptations. I don't know if WGS84, the datum used in GPS, does it, but for example European official datum is ETRS89 which is very similar to WGS84, but adjusts coordinates to these tectonic movements, certain number of cm per year. The principle is to keep same coordinate numbers for same places, even through their global location has changed a bit, even over hundreds of years. In GPS world that does not matter really, but land survey deals with sub-cm accuracy and these things do matter.
• theon144 10y ago
  >As a sidenote, Australia moves about 7cm north annually [1], so any encoding of GPS location is not flexible enough in the long term. In a hundred years, this will be off by 7 meters. I highly doubt that makes a huge difference in addressing a physical building. >Also only encoding lat/long makes it so you would not be able to address a single floor in a large building. As is the case with regular physical addresses.