Australia Is Drifting So Fast GPS Can't Keep Up | Hacker News Reader

Australia Is Drifting So Fast GPS Can't Keep Up

news.nationalgeographic.com

19 pointswanderer429 comments

Try the previous discussion for more details - https://news.ycombinator.com/item?id=12188144

>Corrections have been made to its latitude and longitude four times over the past 50 years, the Times reports. The last adjustment there, in 1994, was about 656 feet.

>The next adjustment is said to be due by the end of this year, on the order of 4.9 feet.

I don't understand. It moved 4.9 ft since 1994, but was moving more quickly before then? The NYTimes article doesn't seem to clarify this either. Were pre-1994 commercially available maps not based on satellite readings of lat/long?

Both the National Geographic article (linked above) and the NYT articles (linked in the Nat Geo) article are fairly low quality. No references or citations. Not up to HN's usual front page quality standard.

Also, the animation over-dramatises what is happening and makes it look like Australia is going to slam into Papua New Guinea soon. That's just.. bizarre.

Why? I think you'd see some earthquake or cresting of terrain when/if it two landmasses slowly but violently merge over years, but I wouldn't know.

First the plate is what's moving not just the landmass. Second it's moving really slowly. They are showing something like a million years of motion, and it's in the wrong direction. https://en.m.wikipedia.org/wiki/Australian_Plate

GPS was barely operational by 1990, so commercial interest would have been there, but probably not a great deal of exploitation.

Th 1994 shift must refer to the adoption of the Geocentric Datum of Australia 1994 (https://en.wikipedia.org/wiki/Geocentric_Datum_of_Australia_... ).

Different datums (models of the shape of Earth) will put the same coordinates at different places. The 656 feet would be the average shift required to reconcile coordinates using the previous datum with coordinates using the new one (which is based on WGS84, the modern global datum).

Before GPS it wasn't terribly useful to know the exact position relative to the entire globe. With a few exceptions (like an ICBM) it is good enough to know location relative to something more local.

Reading this article is quite painful due to all the measurements given only in feet & inches, why not give the data in both systems of measurement? Only 3 countries in the world have not adopted the metric system (Australia did) and this is about GPS and worldwide measurements. Not even NASA uses the imperial units anymore.

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