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2600fromatare, nice photo of your GPS.
I do a lot of GPS work as a hobby and own three Garmins, including a similar one you show in your photo. Two of my Garmins measure elevations by a barometric altimeter, and the other device measures by satellite, not air pressure.
The device you show in your photo measures elevations by barometric pressure. In order for it to be as precise as possible, you must reset the altimeter readings by known elevations.
This being said, I have a bit of a problem with what your photo shows. Your altimeter reads 14,996 feet, but the two odometer readings on the screen show zero feet, the moving time shows 3 seconds, and the stopped-reading shows 17 minutes and 38 seconds. All this indicates that the GPS's altimeter reading was reset at 14,996 feet when you were on the summit. Or, it was an amazing coincidence that your device showed exactly 14,996 feet.
I own a few non-GPS altimeters, including one of the best if not the best Thommen's altimeter. They are all barometric altimeters and must be constantly checked and reset by known elevations on Mount Whitney, or anywhere for that matter, because atmospheric pressure constantly changes.
A photo may speak 10,000 words, but I think your photo needs some clarification, especially concerning Mount Whitney's "official" height. It would be great if Doug Sr. could nail this down for all of us, as "boring" as it may seem.
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Wayne, I don't see the picture by 2600fromatare - looks like the post disappeared To Atare. Whatever, barometric altimeters and handheld GPS units are great for hiking, but they don't really apply to this survey discussion, as I'm sure you'll agree.
Bottom line is that there is no danger of Mt Rainier, or any other mountain, from knocking Mt. Whitney from it's position as King of the Hill in the lower 48. Actually, Mt. Whitney might actually displace Mount Alverstone in Alaska and move up one notch if the official height is now higher than 14,500 ft. It all comes down to the reference datum, which is a moving target.
I don't understand why I saw 14,508 ft on some shirts in the Portal store, I haven't seen this number anywhere else. All this confusion leads to some fun possibilities: should one collect shirts and hats with all the different elevations? or do we have to keep going back to climb the extra foot, or two, or three that the mountain has "grown" LOL
No matter how you look at it, its just another reason to keep coming back...and not at all the most boring topic on this board.
Help Find the Cure for Summit Fever (Not)
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Wayne, Don't know how I missed your post after all these months. The GPS shows 14,496 ft, not 14,996. I did not set it on the summit. I originally set the GPS on the summit of a local peak in San Diego, Cowles Mtn. The reason you're seeing those times and odometer is because I did not turn the GPS on until I reached the summit. I also did not take the picture immediately because the readings were jumping around rapidly as I turned it on. I sat there eating for quite awhile for the unit to "settle" before taking that picture. Hope that helps. 2600fromatare, nice photo of your GPS.
I do a lot of GPS work as a hobby and own three Garmins, including a similar one you show in your photo. Two of my Garmins measure elevations by a barometric altimeter, and the other device measures by satellite, not air pressure.
The device you show in your photo measures elevations by barometric pressure. In order for it to be as precise as possible, you must reset the altimeter readings by known elevations.
This being said, I have a bit of a problem with what your photo shows. Your altimeter reads 14,996 feet, but the two odometer readings on the screen show zero feet, the moving time shows 3 seconds, and the stopped-reading shows 17 minutes and 38 seconds. All this indicates that the GPS's altimeter reading was reset at 14,996 feet when you were on the summit. Or, it was an amazing coincidence that your device showed exactly 14,996 feet.
I own a few non-GPS altimeters, including one of the best if not the best Thommen's altimeter. They are all barometric altimeters and must be constantly checked and reset by known elevations on Mount Whitney, or anywhere for that matter, because atmospheric pressure constantly changes.
A photo may speak 10,000 words, but I think your photo needs some clarification, especially concerning Mount Whitney's "official" height. It would be great if Doug Sr. could nail this down for all of us, as "boring" as it may seem.
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My typo. I meant 14,496.
Setting your altimeter in San Diego will not work for Whitney. It is too far away in distance and time. You need to set altimeters at known elevations as close as you can to your target. You were amazingly lucky to get 14,496, although USGS' official elevation, as maddening and possibly boring as it is to Doug Sr., is 14,505. Now, if your altimeter is a consumer satellite-based altimeter, rather than a barometric-pressure altimeter, that could be another story. I own a Garmin satellite-based altimeter, but I discovered even more erradic and wrong readings more often than not on Mt. Whitney, especially down in the canyons. A professional multi-thousand dollar satellite altimeter with a laser sight, tied in with another or others could do the trick. (Cowles Mtn. is a fun hike. I've done it many times with my altimeters.)
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Hi I like the 14505 elevation execpt is says below the summit ? on the data sheet . Thanks Doug
Last edited by Doug Sr; 12/29/11 04:35 PM.
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A professional multi-thousand dollar satellite altimeter 14508' according to those frames you can buy at the Hostel and WP Store... Since my handheld GPS was reading over 14K on top of Mt. Barnard this past summer (Wayne's son Mike was there to witness it.), I've been looking into a new hobby, but... The Pro Surveying stuff is danged expensive. $2000+ for the Data Collector, $2500+ for the antenna that will give you +/- 4" accuracy, $1500+ for the software to analyze the data when you return to the office... etc (I'm way less than a Rookie, so I don't really know what other equipment may be required...) Anybody know anybody who's willing to give/loan some of this high-dollar equipment to a lunatic climber who's willing to walk around the High Sierra taking readings? (I've got a PayPal account that people can donate to too.)
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Wayne, You're spot on about recalibrating the GPS unit. The manual says to do that for both the altimeter and the compass. Out of curiosity to see how out of whack things would get, I have not done this for approximately a year. Amazingly enough, I have been within 10 feet on San Jacinto in Palm Springs, and Villager in Borrego.   Why fix what's not broken right? I've banged it hard while scrambling up some rocks on Peak 6582, dropped if about 10 feet while going up the South Arete on El Cajon, and abused it with little regard, and it's still working...unlike my Garmin GPS for my car. Go figure. EDIT: ...and what's a guy from NC doing hiking Cowles? Next time you're in San Diego, go up the South Arete in El Cajon, much more fun. It's a good little 3 mile workout.
Last edited by 2600fromatari; 12/29/11 03:20 AM.
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North Carolinian? Not. But a very beautiful state and the most mountainous east of the Mississippi with over 2,700 named peaks. (Colorado has over 6,800 named peaks and California comes in second with over 5,500.)
I'm a third generation native San Franciscan, but lived 27 years in LA and eight years in San Diego. In my eight years in San Diego my goal was to climb all the named peaks (265) in San Diego County, but I only got 62 of them under my feet before a corporate move took me to North Carolina. I did El Cajon two times. I first climbed Whitney 40 years ago. Now you know a little bit more about my NC address. I greatly miss the Sierras.
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