Map accuracy in the Whites.

[RoySwkr]

To answer the original question: most USGS maps of the White Mountains were somewhat accurate when made but there have been a lot of changes since.

In general, the AMC maps are newer and more accurate where there are discrepancies, but you need to use your judgement on the ground as they are not error free and the info is a year old by the time they are printed and older yet based on the date of the map.

As I recall - several years ago Larry Garland used a GPS and hiked the trails, which were then used in the production of the AMC WMNF maps. Aside for minor re-routes, there have been few changes since.

Not quite, most of the trails were GPSed but only a small number by LG personally. Some were not GPSed such as the Owls Head spur and the Mt Davis spur which the AMC maps show both going to the summit although neither actually does. There is no way to tell from the map which trails were GPSed and which are pure speculation.

The latest WMG has new maps using fancier mapping software but there are mistakes which weren't in the previous edition maps which is the sort of thing that happens with anything new.

As noted above, non-trail features may be somewhat mis-located. Streams are tough to define accurately, as flooding can cause a channel to be relocated.

The issue here is that the AMC did not GPS the streams but took them off someone else's base map so they may not register properly with the GPS tracks. When my sister was doing GPS mapping for the USFS she would take a map spot at every brook crossing and adjust the GPS tracks so that's where the crossings would be on the base map. That way, the distance between crossings would be correct and which side of the brook the trail was on would be correct - the items of most interest to hikers. At typical hiking map scales, the width of the line used to show the brook or trail is often greater than the actual width at that scale.

 

[Kevin Rooney]

...Not quite, most of the trails were GPSed but only a small number by LG personally.

Let's not fuzzy up the point, Roy. He may not have done them all personally, but am quite sure either he, or those on his crew (as Thom pointed out) did.

 

[RoySwkr]

Let's not fuzzy up the point, Roy. He may not have done them all personally, but am quite sure either he, or those on his crew (as Thom pointed out) did.

Not all of the trails on the map were GPSed by anybody. I have already named 2 that weren't as shown by their erroneous location on the maps - LG told GD that Owls Head wasn't done because it wasn't an official trail but don't know the explanation for Davis.

 

[Kevin Rooney]

Not all of the trails on the map were GPSed by anybody. I have already named 2 that weren't as shown by their erroneous location on the maps - LG told GD that Owls Head wasn't done because it wasn't an official trail but don't know the explanation for Davis.

Technically, those 2 you mention don't have trails to them. Neither does Isolation, Nancy, Vose Spur, and any number of peaks which have well-worn paths but not formal trails.

 

[Raymond]

I think Roy means that the paths are shown on the maps, but nobody actually traced them out with a GPS.

Neil, what do you mean that you’re a Luddite? I remember a couple years ago a long trip report you filed about a climb you, your wife, and another woman made of Lost Pond Peak during which you lost your camera, but you returned a week later and, using your GPS, retraced your steps and found your camera.

Last September, I lost my camera while climbing Mount Morgan, and it took me 45 minutes to find it, even with a GPS, which I found next to impossible to retrace my route with, and I’d had only a few minutes, not a week, between losing the camera and searching for it to try to remember whether I’d gone this way or that around this tree or that rock.

Your experience was on my mind that day, and I was relieved to have a similarly happy conclusion.

 

[Neil]

Neil, what do you mean that you’re a Luddite? I remember a couple years ago a long trip report you filed about a climb you, your wife, and another woman made of Lost Pond Peak during which you lost your camera, but you returned a week later and, using your GPS, retraced your steps and found your camera.

Hahaha! Busted! OK, I'm sort of a luddite. I use the GPS for certain things.

If I'm going to do a bushwhack with my wife I know she doesn't want any horsing around. As in, well if that ridge is this and this here on the map is that knoll then maybe if we go this way we'll be able to figure it out, that is, if there is a view of this bump.

Lately I've taken to using the gps as little as possible but I will often use it to hit the base (or the top from above) of a slide dead-on.

I would never have found my camera that day without it.

 

[RoySwkr]

Technically, those 2 you mention don't have trails to them. Neither does Isolation, Nancy, Vose Spur, and any number of peaks which have well-worn paths but not formal trails.

Kevin, you are missing the point entirely.

The 27th Edition maps show the trails to Owls Head and Davis in the line style shown in the Legend as "Trail", so it is reasonable for the map user to assume they are official trails and were GPSed. If LG didn't want to GPS them, he should have either left them off (like Nancy) or used a different line style. Both were fixed on the 28th Edition maps as the result of user complaints.

If I have looked carefully at maybe 20 trails on the map and discovered 2 that obviously weren't GPSed because they were in the wrong place, I'll leave it to Dr.D and his students to compute the probable number of other "trails" on the map that weren't GPSed.

 

[Paradox]

I think Roy means that the paths are shown on the maps, but nobody actually traced them out with a GPS.

Neil, what do you mean that you’re a Luddite? I remember a couple years ago a long trip report you filed about a climb you, your wife, and another woman made of Lost Pond Peak during which you lost your camera, but you returned a week later and, using your GPS, retraced your steps and found your camera.

Last September, I lost my camera while climbing Mount Morgan, and it took me 45 minutes to find it, even with a GPS, which I found next to impossible to retrace my route with, and I’d had only a few minutes, not a week, between losing the camera and searching for it to try to remember whether I’d gone this way or that around this tree or that rock.

Your experience was on my mind that day, and I was relieved to have a similarly happy conclusion.

I lost some carbon fiber poles strapped to my pack on a bushwhack last year. I was able to retrieve them on the way down with the help of my GPS. TGFGPS

 

[Raymond]

I lost the knob off the top of my pole last October on East Scar Ridge, but I’m not going to go back looking for it. That would be hopeless. Ditto the rubber pole tips I’ve lost all over the Northeast, the flashing light I lost on Huntington, the water bottles I lost on East Kennebago and East Hancock, the hat I lost on Eagle Cliff ...

 

[Dr. Dasypodidae]

If I have looked carefully at maybe 20 trails on the map and discovered 2 that obviously weren't GPSed because they were in the wrong place, I'll leave it to Dr.D and his students to compute the probable number of other "trails" on the map that weren't GPSed.

Just one student who worked as a field assistant for me on Baffin Island and later worked for Larry in the GPS survey for the new AMC maps. The student told me that all trail junctions were GPS-surveyed with a Trimble navigation system, but I suppose that the Owls Head Path and Mt. Davis Spur might have been neglected.

As far as the most recent USGS 7.5' topo maps from the 1980s, they are far less accurate than the earlier 7.5' and even earlier 15" maps as there was little ground truthing, fewer hours on the zoom transfer scopes for transferring information from aerial photos in the lab, and more automated machine transfer of data as the USGS mapping budgets declined drammatically. The rush to complete these inferior provisional 7.5' topo maps in the 1980s was politically motivated, according to my USGS sources at the time.

 

[RoySwkr]

The student told me that all trail junctions were GPS-surveyed with a Trimble navigation system, but I suppose that the Owls Head Path and Mt. Davis Spur might have been neglected.

That is quite different from GPSing all the trails! Even if you don't arrive at all junctions by helicopter, you could shut off the GPS in between and do no track logs. Or you could do a track log of the Garfield Ridge Trail to hit the junctions, and never walk the Skookumchuck, Garfield, and Gale River Trails. That statement is no indication of what percentage of the trails have actually been surveyed.

Even worse, the AMC doesn't seem to understand the difference between a detailed track log that you may use to retrace your steps and a map which is supposed to present an overall view of the hike to someone who probably doesn't have a GPS and certainly isn't going to digitize the map for a route. The number and location of major stream crossings is important knowledge to hikers who may wish to avoid trails with multiple crossings during high water and may want to know how far apart crossing are to consider bushwhacking between them. If you come to an area where the trail approaches a stream, it is helpful to know whether to look for a crossing or not as there are often paths both ways, so this should be displayed clearly on maps.

Let's take the Wilderness Trail between the Thoreau Falls Trail and Stillwater Jct for an example. Part of this trail follows the old railroad grade and part has been relocated to avoid a double crossing the trains made. The pre-GPS maps (such as 1983) clearly show the dotted line of the trail always on the S side of the East Branch and Stillwater Junction also on the S side. The early GPS maps of the 26th edition use a heavy red line for trails but still show the trail on the S side. However the maps were redrawn for the 28th edition and now show the trail right on top of the river! While this may be technically correct based on line widths drawn to scale or the river may be in the wrong place on the base map, it is not very useful to hikers. Even worse, the new map shows Stillwater Junction to be N of the river while the text and the old maps have it to the S. So the AMC has spent a lot of money on new maps which are less useful even if not technically less accurate.