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Today the New York Times broke the news that after the Clinton Administration turned off Selective Availability in the GPS system, a bug had been introduced into the GPS satellite software itself, causing systematic and large errors in many GPS signals.

Before getting to the question, for background information here is a brief summary of just some of the issues raised by this discovery:

  • It turns out that whereas we thought China was located over 11,000 Km from the US, it's actually only 150 Km offshore of Southern California. One San Diego resident told the Times, "we knew there were a lot of foreign-speaking people coming here, but we all took them to be Mexicans. Who would have thought they were really Chinese? And that Chinese make such good landscape helpers?"

  • Economists have taken notice and are worried. IMF managing director Dominique Strauss-Kahn, contacted at a meeting in Nanjing today, remarked that "economists and business people the world over are going to have to reconsider the global relationships of supply and demand in light of this. I thought the flight over here from LA was a little shorter than it was supposed to be. Mail-order brides are going to be a dime a dozen; US women will no longer be able to compete."

  • Geologists are astir because the entire theory of plate tectonics is now in question. Previously they measured the speed of continental drift at just centimeters per year. Now it looks like the North American and Eurasian plates are on schedule to collide on August 23, 2012, creating a land bridge to the Far East (and completing, in some sense, Columbus's original dream). However, on the bright side, that will prevent California from falling into the sea when the Big One hits.

Here, then, is my question: As a GIS professional, what do you plan to do to check and overhaul your data holdings? What will this comprehensive change in all geospatial coordinates mean for your work?

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closed as not constructive by underdark Jul 31 '11 at 12:33

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

Mods: Feel free to make this CW :-) – whuber Apr 1 '11 at 18:06
Happy Globalisation Day! – Dan Patterson Apr 1 '11 at 22:37
up vote 12 down vote accepted

I will be purchasing ArcGIS Server from ESRI. The sales people assure me that it will solve all these problems.

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i twill not only solve these problems. it will solve all your problems. ArcGis server can make coffee for you if you want. it will just take a lot of time and need a whole lot of hardware. – Nicklas Avén Apr 1 '11 at 19:27
@Nicklas Ah, yes. Here, for the record, is the GIS professional's coffee recipe: Add 1 TBsp freshly ground coffee to 6 oz. clean water in a ceramic cup. Request any geoprocessing operation in ArcGIS. Open computer. Rest cup on the CPU until water boils from the intensive computation. Remove cup carefully, avoiding spills. Filter and drink coffee while waiting. Repeat until the operation is complete. Re-close computer. NB: to expedite the process, partition the data and start as many instances of ArcGIS as you have cores, because it uses only one at a time. :-) – whuber Apr 1 '11 at 20:10
yes, and use the new table you get from each part of the process to put your cup of coffie on. they have thought of everything. – Nicklas Avén Apr 1 '11 at 20:20
@Whuber, you recipie is really great:-). I hope it is ok to cite you on that. another favourite is Paul Ramsey's first comment here – Nicklas Avén Apr 1 '11 at 20:35
@Nicklas Don't get me wrong: I'm not criticizing ArcGIS. One reason it can burn so many CPU cycles is that it can do some really heavy-duty processing. (But the day it learns how to multithread can't come too soon, IMO.) – whuber Apr 1 '11 at 20:58

As I keep all my data projected in moon units, the error is insignificant.

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that sounds interesting. I think the most important thing to do to relly experience this intercontinental bridge is to manipulate the syncronized time in the GPS units ( and the sattellits accordingly) to not leave the date of today. if we could keep 1 of april in the systems for 1.5 years, maybe it will happen.

If so I will absolutely take a quick coure in French since Canada probably will be the part visiting the Nordic countries.

Whuber, can you write the software for looping todays date in the satelites, and GPS units?


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If we could abolish the International Date Line it would remain the same date forever, wouldn't it... – whuber Apr 1 '11 at 18:30
that was an innovative approach to an old problem. I thought alot about it as a child to keep my birthday. do you think it is enough to just cut the line so the current date can pass by or do we have to remove the whole line? – Nicklas Avén Apr 1 '11 at 18:37
I guess there is a risk of unsync in the world dates if it just a small passage in the line. maybe southerm hemisphere will continue to get new dates but not the northen if we just open up a small part in the north. that could cause problems that I don't want to be responsible of. – Nicklas Avén Apr 1 '11 at 18:40

Use the Fix GPS Tool in ArcGIS Geoprocessing

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I'd advise all users of web mapping systems to install this FireFox add-on so Web Mercator coordinates aren't affected by this new bug.

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Since the world is moving into a more convenient setup (take that, cruise ship economy), perhaps we might look into finally removing Greenwich's monopoly on Mean Times.

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