View Full Version : Map accuracy

12-02-2015, 11:10
I've been using the ATC maps, but just picked up the new Nat Geo booklet style map. The distances are off by about 10% on the map I'm using (#1506) versus the ATC guide to Pennsylvania.

Which one should take priority?


Long Haul, section hiker

12-02-2015, 12:16
What specific discrepancies? If you cite specific waypoints, we can look 'em up and tell you what our maps and guides say.. and then figure out which ones are likely to be right or wrong.

12-02-2015, 12:21
The latest ATC maps and guides will almost certainly be more accurate than NatGeo. The GutHook app and AWOL's guide are nice companions to the ATC info.

Tip: For my section hikes I will copy 4-8 pages of a guide to both sides of a sheet of paper and only carry info for the section I'm hiking plus the accompanying map. For longer sections meriting re-supply I will typically include maps and guides for the upcoming section in my maildrop.

12-02-2015, 12:24
The ATC guide as those distances were actually measured on the ground with a wheel. You can't get accurate distances off a map due to the minor twists and turns and ups and downs which don't show up. What your seeing on the map are straight line approximations.

Tennessee Viking
12-02-2015, 12:25
I don't know about PA. But the TN/NC ATC guide books and maps are highly accurate and revised every 2-4 years depending on amount of relocation work. They are GPSed and wheeled.

I have seen Nat Geo maps not get revised for 10 years.

12-02-2015, 15:07
In my experience, guthook and ATC are the best and national geographic the worst with respect to mileage and route changes.

12-02-2015, 16:20
My gf has awols little map set. One discrepency we found was that KSC was marked outside BSP. Was kinda funny.

12-02-2015, 17:37
If a map has pinned waypoints on designated roads or paths, with distances between them, those distances should be accurate, as observed by anyone on that road or path. Of all the sources I could think of, Nat Geo would probably be the one I'd go to last if I were concerned about accurate numbers. I'd trust ATC, ALDHA, AWOL, Guthook before N.G. Just my opinion and gut instinct.