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#11
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Sonora Pass ride description & photos up
"Dan" wrote "Dan Connelly" wrote Dan wrote: clip I'd argue the natural convolution parameter for climbs is the amount one can climb in on a load of ATP, which lasts around 10 seconds. For example, OLH is around 390 meters, so if you can climb OLH in 21:40, this corresponds clip Okay, I had to lookup ATP http://en.wikipedia.org/wiki/Adenosine_triphosphate I have no idea what OLH is. clip Probably Old La Honda, a hill on the Peninsula often used as a test of climbing ability. |
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#12
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Sonora Pass ride description & photos up
I personally prefer "stairway to heaven" over "the golden stairs to
heaven" as in... http://tinyurl.com/8pzvv... it more catchy. Of course, I replaced Led Zepellin's reference to "buying" with "climbing". Steve |
#13
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Sonora Pass ride description & photos up
Dan Connelly wrote:
Dan wrote: I have added a climb per 1/2 mile to the plots linked above. It shows steeper bits steeper but we are headed for the much contested "how to measure steepness" discussion. I am sure we could find a millimeter along the way that is dead vertical if not overhanging. ... Commonly, people suggest discritzation as the way to this end (ie measing th eroad every 15 meters, or half-mile, or whatever). This is an inferior choice, because the result depends on where you start. For example, if you're measuring every 15 meters the the road climbs from 0 to 15, then descends from 15 to 30, the result is profoundly different if you measure at 0, 15, and 30 then if you measure at -7.5, +7.5, +22.5, +37.5. It's way better to oversample then filter down with convolution. Dan This sounds a lot like Mandelbrot's famous question--"How long is the coastline of Britain?" The answer is from something like zero to approaching infinity--depends on the length of you measuring stick. Landscapes including profiles of roads have fractal properties over quite a range of scales. Mike |
#14
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Sonora Pass ride description & photos up
Mike McGuire wrote:
Commonly, people suggest discritzation as the way to this end (ie measing th eroad every 15 meters, or half-mile, or whatever). This is an inferior choice, because the result depends on where you start. For example, if you're measuring every 15 meters the the road climbs from 0 to 15, then descends from 15 to 30, the result is profoundly different if you measure at 0, 15, and 30 then if you measure at -7.5, +7.5, +22.5, +37.5. It's way better to oversample then filter down with convolution. Dan This sounds a lot like Mandelbrot's famous question--"How long is the coastline of Britain?" The answer is from something like zero to approaching infinity--depends on the length of you measuring stick. Landscapes including profiles of roads have fractal properties over quite a range of scales. Mike Precisely. Dan |
#15
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Sonora Pass ride description & photos up
Dan wrote:
"Dan Connelly" wrote in message et... Okay, I am getting in over my head here so cut me some slack if I am off base. I gather from your post that you are suggesting that a Gaussian filter be applied to the data set. My understanding is that this is a low pass filter in the frequency domain. The shape of this filter is non-linear and based on the normal distribution. Filtering and smoothing certainly make a data set look nicer but if the original data set is accurate and contains no noise, filtering and/or smoothing will create a false data set with error introduced into virtually every data point (no post-filter data point represents reality). I have seen otherwise knowledgeable people filter out the interesting part of a data set because they did not like it, understand it or it did not fit their preconceptions. Seeing the world through a Gaussian blur can be rosy but you can also miss important detail. There is also the aliasing problem inherent in discrete sampling but as you suggest, over-sampling will usually take care of this. IMHO, the best way to judge the Sonora Pass climb is to go do it. Do it many times and try changing the variables. The goal is to establish a "peak grade" for the hill which correlates with how hard it is to climb. My point is, even a 100% grade over 1 meter is barely relevent, as inertia, not to mention anaerobic metabolism, allows one to "power" over it (if you don't skid). The low-pass filter is to match the natural low-pass filter of inertia and anaerobic power. My guess is 15 meters is close to the right distance of this "natural" low-pass filter. Dan |
#16
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Sonora Pass ride description & photos up
So I'd convolve the profile with a Gaussian of sigma 15 meters. This
renders as fully irrelevent your 1 mm example, yet a half mile discrization clearly is inadequate at reproducing the feel of the road. My head is spinning. All I did was visually inspect the readouts from the HAC-4 (altitude, distance & percent grade... the latter used only as an indication of where a steep part might have begun or ended, nothing more) and look for sections approximately .6 miles or greater that showed fairly high numbers for percent grade. Then, using the altitude & distance numbers, calculate percent grade over that section. Obviously this won't tell you what the absolute steepest grade is, but it's very good at determining where it's going to hurt the most. --Mike-- Chain Reaction Bicycles www.ChainReactionBicycles.com "Dan Connelly" wrote in message et... Dan wrote: I have added a climb per 1/2 mile to the plots linked above. It shows steeper bits steeper but we are headed for the much contested "how to measure steepness" discussion. I am sure we could find a millimeter along the way that is dead vertical if not overhanging. I'd argue the natural convolution parameter for climbs is the amount one can climb in on a load of ATP, which lasts around 10 seconds. For example, OLH is around 390 meters, so if you can climb OLH in 21:40, this corresponds to 18 vertical meters per minute, or 3 meters per 10 seconds. Using a 20% grade as a reference, this corresponds to a lateral length scale of 15 meters. (okay, actually sqrt(15^2 + 3^2) = 15.3 meters). This result "feels" right to me, based on my history of mental distress at encountering short steep sections of road. So I'd convolve the profile with a Gaussian of sigma 15 meters. This renders as fully irrelevent your 1 mm example, yet a half mile discrization clearly is inadequate at reproducing the feel of the road. Commonly, people suggest discritzation as the way to this end (ie measing th eroad every 15 meters, or half-mile, or whatever). This is an inferior choice, because the result depends on where you start. For example, if you're measuring every 15 meters the the road climbs from 0 to 15, then descends from 15 to 30, the result is profoundly different if you measure at 0, 15, and 30 then if you measure at -7.5, +7.5, +22.5, +37.5. It's way better to oversample then filter down with convolution. Dan |
#17
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Sonora Pass ride description & photos up
That's a really nice photo report. Excellent captions for each photo...
makes for a good story and resource! Since moving to California, it's puzzled me when I see the word "Sierra" pluralized as you wrote "It really is this pretty in the Sierras." Isn't it redundant to pluralize Sierra since it means mountains or mountain range in Spanish? Small issue... I'm just curious. great report, Steve http://www.steephill.tv |
#18
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Sonora Pass ride description & photos up
"steephill.tv" wrote in message ps.com... That's a really nice photo report. Excellent captions for each photo... makes for a good story and resource! Since moving to California, it's puzzled me when I see the word "Sierra" pluralized as you wrote "It really is this pretty in the Sierras." Isn't it redundant to pluralize Sierra since it means mountains or mountain range in Spanish? Small issue... I'm just curious. great report, Steve http://www.steephill.tv You are right Steve, it should be Sierra not Sierras. I suspect that few of use know as much Spanish (or is it Castilian?) as we should. Just as I have gotten used to "PIN number" I have become accustomed to "Sierras." In one way it makes sense because the range varies a great deal. The Whitney region with high granite peaks, The loose rock of the Kaweahs, The Palisades, The Minarets, the Cathedral Range, the volcanic peaks of the east side, the Tahoe peaks, etc. They are all unique sub ranges. |
#19
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Sonora Pass ride description & photos up
"steephill.tv" wrote in message ps.com... That's a really nice photo report. Excellent captions for each photo... makes for a good story and resource! Since moving to California, it's puzzled me when I see the word "Sierra" pluralized as you wrote "It really is this pretty in the Sierras." Isn't it redundant to pluralize Sierra since it means mountains or mountain range in Spanish? Small issue... I'm just curious. Improper Spanish or not it has become common usage in English for the mountains in the Sierra Nevada mountain range. Just like "Rockies" is used for those in the Rocky Mountain range. Speaking of redundancies: Morro Rock, or one the ways to get the Cuesta Grade. Don -- Ever had one of those days where you just felt like: http://cosmoslair.com/BadDay.html ? |
#20
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Sonora Pass ride description & photos up
"Don Freeman" wrote in message ... "steephill.tv" wrote in message ps.com... That's a really nice photo report. Excellent captions for each photo... makes for a good story and resource! Since moving to California, it's puzzled me when I see the word "Sierra" pluralized as you wrote "It really is this pretty in the Sierras." Isn't it redundant to pluralize Sierra since it means mountains or mountain range in Spanish? Small issue... I'm just curious. Improper Spanish or not it has become common usage in English for the mountains in the Sierra Nevada mountain range. Just like "Rockies" is used for those in the Rocky Mountain range. Speaking of redundancies: Morro Rock, or one the ways to get the Cuesta Grade. Don -- Ever had one of those days where you just felt like: http://cosmoslair.com/BadDay.html ? I have always liked "The La Brea Tar Pits" or "The The Tar Tar Pits." |
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