+Tassie_Boy Posted July 28, 2016 Share Posted July 28, 2016 I've finally found a decent excuse for coordinates being off. It turns out were pretty quick here in Oz we've been moving north by 7cm a year, now scientists needs to re calculate latitude and longitude because it's all off by 1.5 meters since the datum was last redone in 1994. Link to ABC article http://mobile.abc.net.au/news/2016-07-28/aust-latitude-longitude-coordinates-out-by-1-5m-scientists/7666858 Quote Link to comment
+Walts Hunting Posted July 28, 2016 Share Posted July 28, 2016 GPSs aren't accurate to five feet so no adjustment needed Quote Link to comment
+eigengott Posted July 28, 2016 Share Posted July 28, 2016 GPSs aren't accurate to five feet so no adjustment needed While that's true for consumer devices, professional GPS/GNSS equipment used by surveyors is accurate to a centimeter. Quote Link to comment
ohgood Posted July 28, 2016 Share Posted July 28, 2016 GPSs aren't accurate to five feet so no adjustment needed While that's true for consumer devices, professional GPS/GNSS equipment used by surveyors is accurate to a centimeter. if you're spend thousands of dollars and hours setting setting it up to find a cache Quote Link to comment
+NYPaddleCacher Posted July 28, 2016 Share Posted July 28, 2016 GPSs aren't accurate to five feet so no adjustment needed There's a decent chance that I may be going to Australia by way of Aukland next June. I would prefer that the coordinates for the runway I'll be landing on aren't off by even as little as five feet. Quote Link to comment
+The A-Team Posted July 28, 2016 Share Posted July 28, 2016 GPSs aren't accurate to five feet so no adjustment needed There's a decent chance that I may be going to Australia by way of Aukland next June. I would prefer that the coordinates for the runway I'll be landing on aren't off by even as little as five feet. If the pilot is so dependant on GPS accuracy that a horizontal difference of a few feet will cause problems for a 100+ x 100+ foot aircraft travelling at 250 feet per second and landing on a 10000 foot runway, I'd look for a different airline! Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 And as I already noted in the related thread about the same issue, it has no effect on caching. Yes, in Australia your gpsr will be 1.5 meters off. BUT THE CO'S GPSR WAS ALSO 1.5 METERS OFF WHEN HE PLACED THE CACHE! The Australian tectonic plate is moving at 7 cm per year (NW, I believe). The trivial adjustment is therefore not 1.5 meters, but the number of years between cache placement and search, times 7 cm. An adjustment of, say, 21 cm (less than a foot) can be ignored in caching. However, sensitive types may get motion sickness in Australia from that tectonic motion. Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 GPSs aren't accurate to five feet so no adjustment needed There's a decent chance that I may be going to Australia by way of Aukland next June. I would prefer that the coordinates for the runway I'll be landing on aren't off by even as little as five feet. If the pilot is so dependant on GPS accuracy that a horizontal difference of a few feet will cause problems for a 100+ x 100+ foot aircraft travelling at 250 feet per second and landing on a 10000 foot runway, I'd look for a different airline! Day or night, the pilot micro-adjusts landing position by sight. If dense fog or a snowstorm is predicted, reschedule the vacation! Quote Link to comment
+Viajero Perdido Posted July 29, 2016 Share Posted July 29, 2016 I'm pretty sure that true zero-visibility landings are still off in the future. It's long been a requirement that pilots be able to see any runway they're about to land on. No runway, no landing. A standard part of pilot lingo is "minimums", whether the airport has enough visibility to safely and legally land. Prang an airplane once, and your career is going nowhere. Heck, if it was really an issue, they'd simply adjust the coords of the runways to account for this. But as an excuse for DNFing a 1/1, heck yeah! Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 (edited) And as I already noted in the related thread about the same issue, it has no effect on caching. Yes, in Australia your gpsr will be 1.5 meters off. BUT THE CO'S GPSR WAS ALSO 1.5 METERS OFF WHEN HE PLACED THE CACHE! The Australian tectonic plate is moving at 7 cm per year (NW, I believe). The trivial adjustment is therefore not 1.5 meters, but the number of years between cache placement and search, times 7 cm. An adjustment of, say, 21 cm (less than a foot) can be ignored in caching. However, sensitive types may get motion sickness in Australia from that tectonic motion. To be more precise, in Australia the gpsr isn't "off," it just differs from published prior (previously-accurate!) GPS coords for a fixed location (including caches). The older the reading for the location, the more it will differ from a current reading. In one year an exact point there changes by 7 cm, as seen from the satellite and with respect to the world as a whole. At that rate cache coords published today will be off by 7 meters (25 feet) in 100 years. No worries - plenty of time to correct! Edited July 29, 2016 by wmpastor Quote Link to comment
ohgood Posted July 29, 2016 Share Posted July 29, 2016 GPSs aren't accurate to five feet so no adjustment needed There's a decent chance that I may be going to Australia by way of Aukland next June. I would prefer that the coordinates for the runway I'll be landing on aren't off by even as little as five feet. the pilot doesn't care. he has charts that he can use to navigate to anywhere in the world in his iPad/iPhone. all he(or she) needs is fuel and line of sight. Quote Link to comment
+MartyBartfast Posted July 29, 2016 Share Posted July 29, 2016 ... all he(or she) needs is fuel ... Not necessarily: http://www.bbc.co.uk/newsround/36892822 Quote Link to comment
+NYPaddleCacher Posted July 29, 2016 Share Posted July 29, 2016 GPSs aren't accurate to five feet so no adjustment needed There's a decent chance that I may be going to Australia by way of Aukland next June. I would prefer that the coordinates for the runway I'll be landing on aren't off by even as little as five feet. the pilot doesn't care. he has charts that he can use to navigate to anywhere in the world in his iPad/iPhone. all he(or she) needs is fuel and line of sight. My post was mostly a joke to point out that lat/long coordinates aren't used just for geocaching. Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 the pilot doesn't care. he has charts that he can use to navigate to anywhere in the world in his iPad/iPhone. [/Quote] Book me on the flight with the left-brained pilot using Samsung / Android, please! Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 (edited) ... all he(or she) needs is fuel ... Not necessarily: http://www.bbc.co.uk/newsround/36892822 Not all fuel needs to be stored in a fuel tank on the plane. Edited July 29, 2016 by wmpastor Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 My post was mostly a joke to point out that lat/long coordinates aren't used just for geocaching. [/Quote] No doubt about it! Those satellites were launched knowing that one day they'd be used to find Pikachu at the park! Quote Link to comment
+on4bam Posted July 29, 2016 Share Posted July 29, 2016 Book me on the flight with the left-brained pilot using Samsung / Android, please! Not approved yet. Only Ipad. As for the Australian drift, there's also a drift of the magnetic north. Our local (EBBR) 2/20 runway was renamed 1/19 last year. Most used 25R is still 25R. Quote Link to comment
+wmpastor Posted July 29, 2016 Share Posted July 29, 2016 Book me on the flight with the left-brained pilot using Samsung / Android, please! Not approved yet. Only Ipad. As for the Australian drift, there's also a drift of the magnetic north. Our local (EBBR) 2/20 runway was renamed 1/19 last year. Most used 25R is still 25R. To update the Greek philosopher's 2,000-year-old wisdom, "A pilot cannot land on the same runway twice, because he/she is not the same person, and it is not the same runway." Quote Link to comment
+Ralfcoder Posted August 4, 2016 Share Posted August 4, 2016 Book me on the flight with the left-brained pilot using Samsung / Android, please! Not approved yet. Only Ipad. As for the Australian drift, there's also a drift of the magnetic north. Our local (EBBR) 2/20 runway was renamed 1/19 last year. Most used 25R is still 25R. Sounds like the continent is not only moving north, but it's doing the twist as well! Is this the real reason that water drains counterclockwise? Quote Link to comment
+on4bam Posted August 4, 2016 Share Posted August 4, 2016 Is this the real reason that water drains counterclockwise? Quote Link to comment
+wmpastor Posted August 4, 2016 Share Posted August 4, 2016 Is this the real reason that water drains counterclockwise? Not only that, it's the reason "leap seconds" are sometimes added to the calendar! Quote Link to comment
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