4 ms·

It still boggles my mind how three different GPS position formats can be used. And then not used correctly by search crews, which then missed location by 23nm.

• thaumaturgy 9y ago
  Yeah, coordinates are a pain in the ass, and here they're even using the same coordinates, just with different formatting. There's also UTM, deg-dec-min, deg-min-sec, and you have some differences between WGS84 and NAD27, and every group has their own preferences for their own reasons.
• fwip 9y ago
  23 nanometers off, dang. If they'd only had a slightly wider field of view, they could have found those poor people. :(
  • AceJohnny2 9y ago
    Nautical Miles
  • bjt2n3904 9y ago
    Perhaps a little poor taste with the tone, but this is a great point. We're all talking about how poorly we handle units. Nm has two meanings, but I didn't even think about it until this comment.
    • fwip 9y ago
      Good point; I should have been more careful with my wording.
    • jzwinck 9y ago
      Nm is Newton meters. You're looking for NM (Nautical Miles). Common mistake. Similarly, kt means knots as in speed, but the very same kt also means kilotonnes as in dynamite.
• thisrod 9y ago
  Those formats are simply insane. It's well known that some people use decimal fractions of degrees, so why would anyone even consider using a decimal point to separate degrees and minutes?
  • dreamcompiler 9y ago
    Was this a big problem before computers? I doubt it. Back in the analog days two people would engage in a dialogue and ensure the units were agreed upon. Now people just blindly type data into a screen, or two computers blindly exchange packets without proper metadata. It's ironic that we have 1000x better navigational accuracy than a 19th century tallship captain but we're much more careless with the data than he would have been.
    • thisrod 9y ago
      I don't think it's carelessness, rather that 1000x more accurate navigation gives you a lot more things to care about. That 19th century captain measured the angle between the pole star and the local horizon with a sextant; the cartographers did it the same way, because that was the only thing you could do. Today, we work with atomic clocks, and our instruments fabricate an angle between the z-axis and a 100th order spherical harmonic series that models the shape of the ocean surface. Every few years, we update the model to keep up with plate tectonics. (Not exactly, but you get the idea.) There are a lot more things to go wrong, and not everyone programs in sanity checks to prevent small corrections from causing large errors.
      • dreamcompiler 9y ago
        Fair point. > That 19th century captain measured the angle between the pole star and the local horizon with a sextant; Which immediately provided latitude. To get longitude, he did the same with just about any other star and correlated the angle to an accurate clock and carefully-prepared tables. That "accurate clock" business was why longitude was such a difficult navigational problem for so long until John Harrison finally cracked it. (I know this is getting OT but I find it fascinating.) https://en.m.wikipedia.org/wiki/John_Harrison https://en.m.wikipedia.org/wiki/John_Harrison