I remember that it took me an hour to go 0.6 mile downhill from the Garfield water source !Originally Posted by Jack Tarlin
Sorry I missed previous rounds. I should first acknowledge being aware that most work producing such maps is the work of volunteers and that in every trip I've been grateful to have such maps, inaccuracies and all. And no doubt there are some cases of "inaccuracies" which are actually nothing more than a map that is out of date, and I wouldn't expect a volunteer organization to be able to release new maps for every reroute, and still keep the cost of the maps down.
Nevertheless, I stand by my assertion that there are many cases inaccuracies are inaccuracies, and they cannot be explained away by scale. There are many instances where elevation changes on the trail occur on a large enough scale over a large enough distance that they would show up clearly on correctly drawn elevation profiles, but the maps do not match the actual trail.
I can show you other cases where the map with an elevation profile ON THE SAME SIDE OF THE SAME SHEET OF PAPER do not have any plausible way to be reconciled. If I get around to it, I may scan images and post them. It will be harder to demonstrate inconsistencies between the actual trail and the map because we won't be able to take a field trip together.
That being said, hats of to the Georgia trail club. Their maps were so accurate I could gauge distance by noticing a very small change in gradient on the trail and matching that to the elevation profiles.
if you can think of an area between waynesboro and grafton notch, i have the map. i would however like to point out the differences in scale between the map and the elevation profile. now if youve seriously ever encountered an area where the trail went downhill for a mile where the profile said it should be going uphill, youd have me convinced. ive yet to ever run across anything even remotely like that. that there may be what seems on the ground to be very steep uphills in an area the profile shows as flat are a matter of scale and nothing more.
I feared for my life dropping down the Beaver Brook trail on the north/east face of Moosilauke. The entire Mahoosuc section seemed impossibly steep.
I too feared for my life on this section. I left Hanover that morning planning to stay at Beaver Brook, but I let the locals talk me into going past it to the next shelter (since it was only 1:00). What a mistake. I got to the next shelter ( can't recall the name right now) at dark, physically and mentally beat to a pulp. That'll teach me to ignore my intuition and listen to others.
Seek, and you shall find.
your plan was to hike 53 miles and the locals in hanover talked you into trying to hike 60 instead? and you made it!?!?! yeah i'd feel beat up by then too.I feared for my life dropping down the Beaver Brook trail on the north/east face of Moosilauke. The entire Mahoosuc section seemed impossibly steep.
I too feared for my life on this section. I left Hanover that morning planning to stay at Beaver Brook, but I let the locals talk me into going past it to the next shelter (since it was only 1:00). What a mistake. I got to the next shelter ( can't recall the name right now) at dark, physically and mentally beat to a pulp. That'll teach me to ignore my intuition and listen to others.
also odd that the 53 miles only took you until 1pm and the remaining 7 took you until dark.
or did you mean glencliff?
I've hiked most of SNP up through Pen Mar State Park. I did much of SNP after having gained enough hiking experience to be in tune with discrepancies. I would agree that through SNP the maps are well aligned with the reality of the trail. My earliest hikes were Maryland, and VA north of SNP. Although I don't recall any discrepancies, I really didn't have enough experience for my own perception to matter a whole lot for that region.
Georgia, also is very accurate.
Virginia, south of Waynesboro, on the other hand, has a number of inaccuracies that cannot be discounted by scale. Also, in northern TN, around Pond Mountain, I happened across a friends version of that map and compared it with my more recent edition. If I can get a hold of my friends map, I'll scan the two and put it up for discussion. Personally, I think it is a smoking gun for the argument that "fudging" has taken place, and I'm more convinced so after having hiked the region. A healthy skepticism on your part is good, especially if you've largely found the maps of the places you've hiked to be accurate. But I would suggest you wait and see. Presumably you'll get around to hiking south of Waynesboro (I've hiked up to the James River and can confirm bona-fide inaccuracies in Virginia at least up to the James River). You're in for a few surprises if you're carrying elevation profiles.
I have a map in front of me now that is typical in its scale. Looks like about 1 vertical cm for 500'. Would you agree in principle at least that a 300' climb over half a mile should not look flat on this profile?
YES I MEANT GLENCLIFF! THANK YOU FOR CATCHING THAT. I thing the shelter I stayed at was Eliza Brook.
Seek, and you shall find.
I need a correction option on here for spelling and brain cramps. :0
Seek, and you shall find.
i dont have a map in front of me to stare at and ponder the question. i'll get back to you.
ill also concede you may be entirely right about southern VA and maybe the trail club there is out to lunch, who knows. but if so its very isolated. you yourself attest to GAs accuracy, and i'll vouch for the 1000miles or so ive hiked. that doesnt leave much left that could possibly be all that wrong.
it's always steeper then it looks on the map.
always.
sure, but does that mean the map is wrong?
this is the same sort of argument that pops up every so often where someone will insist the distance between some point a and some point b is actually several miles longer than the maps claim (and then usually follows all sorts of bizarre theories as to why).
actually theres been a time or two when i was expecting worse based on the profile, but it is rare.
I've usually found that "easy" sections are never as easy as I expected. But also the sections that look like they're going to be very difficult are not quite as hard as I feared. I haven't done NH yet though.
Also, most people I talk to tend to overestimate the distance they've walked unless there are concrete milestones to measure by. In almost all cases where an unofficial source gives a measure for a side trail, it grossly overestimates the distance. If someone says a side trail to a spring is 0.3 mile, then usually it's really only about 0.1 of a mile. If the measurement comes from a more "official" source, then it is more likely accurate.
If the maps sold by the ATC show a distance different than the guidebooks sold by the ATC, usually the guide books are correct (at least in the areas I've been hiking).
Well, I'm glad to hear most of the northern AT has accurate elevation profiles. From the VA/TN border to the James River is over 300 miles. From there it is about 80 more miles to Waynesboro, which I haven't hiked, but would expect the same degree of accuracy as the other 300 miles. And in TN, at least the Pond Mtn area has what appears to be fudging. That's more than half of the 600+ miles I've hiked were on sections that had questionable accuracy. The whole NC/TN section is almost 400 miles that I can't give much opinion one way or the other.
the carters were a bit decpetive, alot more puds than i anticipated.
but although ill look at the maps in the am before i start, i generally just pick my end point for the day and start walking, taking whatever the terrain gives me. by midday, ive got a pretty good idea where ill end up.
im still trying to figure out why most guidebooks are written sobo.
i had to walk backwards through new hampshire!
i'm looking at a SNP map and yes, i would agree. i would also point out that while walking a 300 foot gain over 1/2 mile is something i might not even notice. i certainly wouldnt think of it as uphill. id be willing to go so far as to say that if the map called this flat i probably wouldnt care enough to notice
its the much shorter, steeper changes in elevation that get lost, which makes it seem more egregious an error. looking at a map of the same scale would you agree that a +200 foot change followed by a -200 foot change that occurred within 1/10 of a mile wouldnt even register due to scale?
also scales are not consistent. the SNP maps are very big. looking at the VT/NH maps, the same spacing that represents 500 vertical feet on the SNP maps represents over a 1000 on the VT/NH maps. does this make this profile inherently less accurate? yes. was using this scale instead of the one that the PATC uses for SNP a bad decision? arguably, but you have to consider how much bigger than anything in SNP mount washington is. does this mean the VT/NH maps are wrong or that the people who made them could have done a better job or that they havent been updated in a very long time? not at all.
Climbing Moosilaukie from the North might qualify - not sure.
Hmm. Perhaps your hiking in NH has gotten you in a lot better shape than me. I've noticed a common AT grade is around 500' per mile. For places that can add switch backs and can choose to go longer and less steep, or shorter and more steep, they seem to target about 500' per mile. And I ALWAYS feel the burn at that rate, although it's not so steep I can't keep walking. So a 300' rise in 1/2 mile, being slightly steeper is something I would notice. 300' over a mile, I would breeze through. 1000' over a mile would emotionally scar me.
A 200' drop followed by a 200' rise in 1/10 of a mile, I guess could get left out completely. That would be a grueling 0.1 mile.
I tend to procrastinate such things, but today I actually scanned some images to put up for discussion. Stay tuned.
a quick glance at SNP (again, going for something we have in common) i see hogback mountain seems to climb about 500 feet in under a mile. thats about the steepest thing i remember in SNP. thats not steep. i was exaggerating a bit when i said i wouldnt even notice 300 feet in 1/2 mile, or perhaps i was mentally thinking in 1 mile. my 1/10 example was a little over the top also, but lets say 100 feet up and down in 1/4 mile? if that did register itd be a tiny zig on the NH maps. if you look at mahoosuc arm, which a few in this thread mention, youre looking at 1500 feet or so in about 1.5 miles. with the scale the map is printed at quick changes of 100 feet dont show up much at all, and there are alot of them in the mahoosucs. if you try and count how many hills youve gone over relative to what the profile shows up there to try and determine where you are youll find yourself constantly nowhere near where you think you are, which could easily lead one to incorrect conclusion that the maps must be wrong.
Okay, hopefully this image uploader will work properly. The first image shows Laurel Fork Shelter to Pond Flats (Northern TN) from the ATC map copyright 2005.
The second shows the same region copyright 2006.ATComp0002.jpg
First of all, the regular map of the section does not show a change. It seemed to match what I remember hiking. The first elevation profile shows about a 3 mile distance. The second shows the south side of the mountain being less steep, and the whole distance from the shelter to Pond Flats as being close to 4 miles. The AT databook lists this distance as 3.8 miles.
This cannot be explained by a reroute unless we accept that they accounted for the reroute in the Elevation profiles, but not the map. Also, it is very hard for a reroute to make a whole 1800' climb less steep unless the whole route is changed. They couldn't just reroute a short section and result in the whole section having less steepness. Also, I recall it being flat leaving the shelter for much further than shown on the newer map. And the south side of the mountain was noticeably steeper than the north side. The 2006 map appears to be a "fudge" to align the distance with the AT data book without any real attempt to align with the actual elevation profile in the region.
For planning purposes, it was an 1800' climb, so the map was still very useful.
I've got another example that is even more profound.
Here are elevation profiles for just south of the James River footbridge. I've also attached the terrain of the area with the AT center line
from the ATC interactive map. I was just there this spring, and I can tell you the ATC interactive map is very much aligned with the reality of the trail and the topography of the region. On the other hand, the elevation profile of the section shows a descent from Big Cove Branch of over 1000' followed by a nearly 500' rise to Matts Creek Shelter. This followed by a peak that is almost 800' higher than the James River.
From the ATC interactive map, Matt's Creek shelter is at least 400' off in elevation versus the elevation profile. And there is not even a plausible route through the region that would result in descending 500' below Matt's Creek shelter. I cannot come up with any reasonable hypothetical re-route that would have ever matched this profile. And even if that were possible, Matts Creek shelter didn't move. I didn't scan it, but the map that goes with the elevation profile is completely aligned with the reality as shown on the ATC interactive map. So again, it is not even consistent with the elevation profile that is on the same side of the same map.
Obviously we can't take a field trip to confirm that the elevation profile is wrong, but anyone that has hiked the region can call me on it if I'm wrong about this. Going south from Matts Creek shelter, there is no descent. It is uphill for 1000+ feet. And going north there is only about a 200' drop to the level of the James River and that is over a mile or two.
This is one of the more egregious discrepancies. There are many more subtle ones that are significant enough that the elevation profiles should look different, and that cannot be discounted by scaling.
ATComp0003.jpgATComp.jpg
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