View Full Version : Total Elevation Gain
Does anyone know the total elevation gain. This couldn't be figured out by just adding up the different mountain elevation gains. It would most likely have to have been done by someone thru-hiking with GPS. I'd love even a close estimate. Thanks
fiddlehead
09-29-2008, 23:03
I wonder if you could take the line that someone put out there (and i downloaded) onto Google earth of the trail, and get the figures from that?
You would think it certainly should be possible although hiking with a GPS turned on for the whole trail and keeping track without resetting the thing for the whole trail would be much more accurate (except for perhaps blue blazes into shelters and such and they'd have to turn it off when they went to town.
Good question.
I think I would try the kmz file first. Maybe if you had the pro version of GE, something could be done. Maybe their forums would help. I don't really have the time myself and am working on other things.
(well right now, i'm watching Monday night Football) priorities, aye?
The Old Fhart
09-30-2008, 05:33
As the tee shirt I bought says: "Like climbing Everest 17 times". The figure used is 506,000 feet. Obvious some will disagree with their analogy but the mathematics are probably close.
I have GE-Pro, And a MASSIVE .GPX file with 33-foot segments of the entire trail... unfortunately, to reduce file size, the original maker got rid of the elevation data,
I've been calculating elevation profiles (of 20-30 mile section hikes, at 100 foot segments) with Garmin's Mapsource, But for some reason you have to Draw the trail in order for it to snap Elevation-Data to it... meaning... if i wanted to get the Elevation Data from the entire Appalachian Trail, I would have to click on something like 340,000 points...
sasquatch2014
09-30-2008, 11:20
And that is stopping you why?:rolleyes:
There is an article in the articles section with all the data
Mr. Parkay
10-02-2008, 20:14
I could make the calculation... I'll give it a shot sometime soon
Mr. Parkay
10-02-2008, 21:24
Hey guys,
This is in response to several previous posts.
1. A few weeks ago I posted detailed elevation profiles for the whole AT. They are available free for download on my makeshift website: parkaymaps.110mb.com (http://parkaymaps.110mb.com/)
2. In order to accomplish this I had to solve all of the technical issues mentioned earlier in this thread. So If anybody needs elevation data for the AT, then feel free to send me a PM... I've got the goods.
3. In an earlier post, Totem mentions the problem of getting elevation data into the google earth track. Here's a quick explanation about how to solve the problem using freeware software: 1. Use GPSbabel to convert the google earth file into .gpx format 2. Use Wissenbach map to add elevation data to the track (using elevation data gathered by NASA). 3. Use GPSbabel to convert the .gpx file (with elevation) back to google earth kml format. In my opion, the result will be as good or better than the elevation data collected by standard GPS units. Note: the process is not as simple as I make it out to be, so if you try it yourself you'll run across alot of problems, which will take a while to figure out.
4. There exists a much more difficult technical problem that you might run across if you try to make profiles derived from the ATC's AT center line (or the similar PCT center line). The problem is caused by gps tracks that have a disorganized internal stucture (thousands of segments, organzied randomly, each going in different directions). I had to write a computer program re-organize data points in order to create the "continuous" at profile on my site.
Anyhow, just thought I'd share some of my notes, since I've spend entirely too much time working on this sort of thing :)
--Parkay
Mr. Parkay
10-03-2008, 01:45
Hello Again,
I made the calculation for the total elevation gain for the AT, PCT and CDT. Here are the results:
AT total elevation gain: 490,694 feet
PCT total elevation gain: 546,880 feet
CDT total elevation gain: 407,708 feet
I'm not sure what accounts for the difference between my calculations, and the one mentioned by The Old Fhart.
Anyhow, It's interesting that these figures indicate that the AT has more elevation gain than the CDT, even though the CDT is considerably longer. I'd say this is because the desert in New Mexico is so flat, much flatter than the desert on the PCT for example. Also, a lot of the CDT follows roads, which are also relatively flat in general... this is all assuming that I did the calculation correctly.
What program do you use to output the actual elevation profile? Does it default it to PDF?
map man's article says 515,000 feet based on unearthly patience with analog maps. The difference among the three values cited to date in this thread is in the second significant figure.
My guess as to why Mr. Parkay's method gives just a little bit smaller result is from the nature of matrix math.
The elevation raster data always will average an elevation over a given cell size and assign that value to the entire cell. With better data becoming available, the cell sizes get smaller and this error diminishes.
However with a footpath route's nature to go to the highest and occasionally the lowest point along an averaged track length, these points of extreme elevation high and low over the segment are more likely to be captured by the analog method than from an elevation matrix.
Either that, or the mountains have eroded off a bit between when the USGS folks made the quad maps and when the elevation data was captured. ;)
Mr. Parkay
10-03-2008, 23:09
Thanks for the wise words Ki0eh! I must say that calculating this figure based on analog maps certainly would take an unearthly amount of patience!
I might try doing the calculation again using more data points... to see if it makes any difference. The track I used is a simplified version of the ATC center line with "only" 100,000 data points, whereas the full version has closer to 300,000. My assumption is that the difference is would not be significant, but I could be wrong about that.
map man's article says 515,000 feet based on unearthly patience with analog maps. The difference among the three values cited to date in this thread is in the second significant figure.
My guess as to why Mr. Parkay's method gives just a little bit smaller result is from the nature of matrix math.
The elevation raster data always will average an elevation over a given cell size and assign that value to the entire cell. With better data becoming available, the cell sizes get smaller and this error diminishes.
However with a footpath route's nature to go to the highest and occasionally the lowest point along an averaged track length, these points of extreme elevation high and low over the segment are more likely to be captured by the analog method than from an elevation matrix.
Either that, or the mountains have eroded off a bit between when the USGS folks made the quad maps and when the elevation data was captured. ;)
Mr. Parkay
10-03-2008, 23:23
Hey Totem,
I use matplotlib (http://matplotlib.sourceforge.net/backends.html) to output the profiles. It allows you to export the profiles in PDF format by default. I prefer pdf because it is a vector based, which keeps the file size small when I'm creating oversized profiles. Most other file formats tend to break down if the profile is too big.
What program do you use to output the actual elevation profile? Does it default it to PDF?
Alright, I went ahead and calculated the Total Elevation Gain using the Full Resolution (312732 points) ESRI Data for the Appalachian Trail
529,051' Gain
527,662' Loss
At an approximated 29,000' gain for it... It's like climbing Mount Everest over 18 times!
I'm contemplating posting the Full Resolution .GPX (and .KML/.KMZ somewhere, but I haven't the bandwidth on my server for it.
Also, It calculated the total length to be 2,473 miles, nearly 300 more miles than the 2,175 mile figure. I believe if you walked the extremes of every turn (walking on the outside of zigzags, large curves and bends, etc) you'd get a little closer to this figure but the number is much higher due to ESRI's preciseness of trail resolution.
Also keep in mind, there is much lost in translation between walking it with a measuring wheel, recording it on GPS, transliterating analog topo maps and working with digitized maps.
Mr. Parkay
10-09-2008, 17:11
Also, It calculated the total length to be 2,473 miles, nearly 300 more miles than the 2,175 mile figure. I believe if you walked the extremes of every turn (walking on the outside of zigzags, large curves and bends, etc) you'd get a little closer to this figure but the number is much higher due to ESRI's preciseness of trail resolution.
Also keep in mind, there is much lost in translation between walking it with a measuring wheel, recording it on GPS, transliterating analog topo maps and working with digitized maps.
Hey Totem,
It's interesting that your calculations add miles to ATC's figures. Whenever I do the calculation, I always end up with a smaller number.
My calculations give a "flat land" distance of 2107.1 miles for the AT using the 312732 data points. But after I factored in the extra distance added by mountains, the number increases to 2125.18 miles. Still 50 miles short of the ATC's figures, which I'm guessing were calculated with a measuring wheel.
Anyhow, I just re-calculated the total elevation gain using the 312732 data points. This gave me a total gain of 509,589 feet... Pretty close to the 515,000 estimate given in Map Man's article. Using all of the data points made a lot more difference than I had expected.
Thanks for the great information. I had fun scrolling along the AT.