Unusual to see a metric-primary article on MSNBC although the press agency is Reuters, and the original source a Chinese news conference.

http://www.msnbc.msn.com/id/9638192/
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Survey: Everest shorter than previously thought
China says measure is more precise, doesn't suggest mountain is shrinking

Updated: 7:26 a.m. ET Oct. 9, 2005
BEIJING - China now thinks Everest, the world’s highest peak, is about 3.7 meters (about 12 feet) shorter than its own past estimates after conducting a new survey of the mountain this year, state media reported on Sunday.

Mount Everest stood 8,844.43 meters above sea level, with a margin of error of about 0.21 meters, Chen Bangzhu, Director General of the State Bureau of Surveying and Mapping, told a news conference.

Chinese mountaineers and researchers climbed to the top of Mount Everest in May to determine whether the world’s tallest mountain was still growing.

Chen told reporters on state television the updated figure did not mean the mountain had shrunk over time.

“The data is so far the most detailed and precise among (those from) all previous surveys domestically and internationally,” the official was cited by China Central Television as saying.

“We cannot arrive at the conclusion now that the Everest has become shorter, because there have been problems ... of surveying technology with previous measurements.”

In 1975, Chinese scientists measured the height of Everest at 8,848.13 meters (29,029 feet, 3 inches), a few centimeters more than an Indian survey had found in the 1950s.

Then in 1999, a U.S. team measured the mountain -- known to Chinese as Qomolangma and straddling the border between China and Nepal -- at 8,850 meters.
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Wikipedia states the 8850 m reading was obtained via GPS readings from a device placed on the summit by the USA in 1999. Everest is still growing due to the plate tectonics of the area, adding 3 to 5 mm to the height and moving north-eastward at 27 mm per year.

It also says:

The mountain is approximately 8,844 m high, although there is some variation in the measurements. On 22 May 2005, the People's Republic of China's Everest Expedition Team ascended to top of the moutain. After several months' complicated measurement and calculation, on 09 Oct 2005, the PRC's State Bureau of Surveying and Mapping officially announced the accurate height of Everest is 8844.43 m. They claimed it was the most accurate measurement to date.[


In other words, the Chinese came to their result by complicated measurements and computations (hopefully using a computer and not with pencil and paper) and the Americans used a device and the GPS system. The difference is 5.57 m. The actual height all depends on who you trust, the computerized GPS or the manual method used by the Chinese. What is the percentage error in either method of measurement?

GPS is less accurate for vertical than for horizontal position. Without knowing the equipment used, it is hard to say. A single GPS is NOT as accurate as the Chinese claim their error is. With differential GPS, using a second unit on a well surveyed monument, it might be that good. However, centimeter GPS is pretty good for the technique, and require post-processing, and can be regarded as "complicated."

More routine accuracy is around 1 m realtime for differential GPS, maybe 2-5 m for military single GPS (they use two frequencies), and 5-10 m (all horizontal, vertical is worse) for civilian. For equipment that logs the necessary data, post-processing can improve this after errors in the GPS constellation are analyzed; this is very complex and I don't understand exactly how it is done, but it is the basis of GPS surveying, not just reading the units in realtime.

If the Chinese can defend their their claimed ±0.21 m error, I'd probably go with them.

Why are people posting news events that have some metric notation in them?

This site could get very crowded if everyone did that.

<<Why are people posting news events that have some metric notation in them?
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IMO, metric news in metric countries probably shouldn't be. When the US media uses metric as primary, and not all (feet) values are even given, it IS a commentary on metric usage in a Customary country, and potentially qualifies as a discussion item.

I will also add that I have since seen other US media outlets who published later convert every figure in the article to feet and omit the metric dimensions entirely. (Yahoo is an example)

Wouldn't that be more to do with catering for the customer's (readers) native tongue than any metric vs imperial thing?

<<Wouldn't that be more to do with catering for the customer's (readers) native tongue than any metric vs imperial thing?>>

They certainly need to translate the Chinese to English. LOL

As for the units, it is a judgement call. Of course, that is exactly what makes it a debate item and we will probably have some differences of opinion. They are summarizing what he said, not literally quoting, but I tend to think they made the right decision staying with "original units" reported by the team. They can they decide how much supplemental to include parenthetically. To me, that is a better choice than wholesale conversion to feet.

Anybody who cares about the nuance of these minor height differences, the claimed accuray, or the equipment to measure it probably understands metric, even in the US. For the rest, it is 29,000', give or take, in any of these measurements.

Concidentally I read this news item in my newspaper last night and thought of you lot here!