AMC White Mountain Guide Online - Accurate Coordinates?

[Kurchian]

I recently subscribed to AMC's online White Mountain Guide system. For those not familiar with it, it basically allows you to easily create customized trips that show not only the maps but the trail descriptions, trail distances and elevation changes. It is easy to use and saves me the trouble of photocopying descriptions.

So, I am readying for #47 to Owl's Head and I printed out their descriptions. Since I am a GPS user I was interested to see what coordinates were listed for the departure point to the Owl's Head slide. They are listed as 44 08' 16", 71 36'57". These coordinates appear to be off. I checked them on my TOPO! software program and entered them into my GPS and that coordinate appears to be halfway up the mountain, way off the Lincoln Brook Trail.

I've checked some other coordinates from this program and they seem equally off.

I am curious if anyone has used the coordinates from this program and if they've had any problems. Or, perhaps my sense of the slide start coordinates are wrong?

 

[Paradox]

I recently subscribed to AMC's online White Mountain Guide system. For those not familiar with it, it basically allows you to easily create customized trips that show not only the maps but the trail descriptions, trail distances and elevation changes. It is easy to use and saves me the trouble of photocopying descriptions.

So, I am readying for #47 to Owl's Head and I printed out their descriptions. Since I am a GPS user I was interested to see what coordinates were listed for the departure point to the Owl's Head slide. They are listed as 44 08' 16", 71 36'57". These coordinates appear to be off. I checked them on my TOPO! software program and entered them into my GPS and that coordinate appears to be halfway up the mountain, way off the Lincoln Brook Trail.

I've checked some other coordinates from this program and they seem equally off.

I am curious if anyone has used the coordinates from this program and if they've had any problems. Or, perhaps my sense of the slide start coordinates are wrong?

This is not the answer to your question, but Here is a wikiloc link to the route we took to Owl's Head via the "Brutus Bushwhack".

 

[GlennS]

I just looked at a saved track we took one winter using Garmin's Mapsource software.

It shows the start of the slide at about N44 08.241 W71 36.954. It was winter with a lot of snow on the ground so the entry to the slide may be a little off.

Are you using the same Datum? Mine is using WGS 84

 

[nartreb]

Those coordinates look about right to me:

http://mapper.acme.com/?ll=44.13778...=44.13778,-71.61584,N 44 08' 16" W 71 36'57"

Acme mapper uses WGS-84.

Reading off my paper AMC map gives approx the same coords (hard to get precise coords off the map)

 

[DougPaul]

As others have noted, check to make sure that you are using the same datums. When multiple points are off by the same amount and direction, this is a very likely cause. A set of coordinates is meaningless without the datum...

The most common datums used in hiking are WGS84 (the GPS default) and NAD27 used on some of the older USGS topos. The difference is ~220 meters in the Whites. GPSes and mapping programs generally have settable datums.

Doug

 

[Dr. Dasypodidae]

I just looked at a saved track we took one winter using Garmin's Mapsource software.

It shows the start of the slide at about N44 08.241 W71 36.954. It was winter with a lot of snow on the ground so the entry to the slide may be a little off.

I think that I might remember that GPS track.

 

[Drumhaggart]

Not an answer, but...

This doesn't answer your question, but as a practical matter, the slide's departure from the Lincoln Brook Trail is easy to identify...

someone, apparently thinking it would be helpful, had hacked a crude arrow-shaped blaze into the trunk of a tree at the point where the slide path departs to the right.

_________
Steve

 

[GlennS]

I think that I might remember that GPS track.

Yes, that trip was quite memorable.

 

[RoySwkr]

This doesn't answer your question, but as a practical matter, the slide's departure from the Lincoln Brook Trail is easy to identify...

someone, apparently thinking it would be helpful, had hacked a crude arrow-shaped blaze into the trunk of a tree at the point where the slide path departs to the right.

That is only a temporary help, the FS will no doubt cut the tree down to eliminate this landmark

People with good woods sense will have no difficulty finding the worn path up the gravel outwash, and I think the coordinate from Acme Mapper should be fine to get you looking in the right area

But I'm curious about the original question, if there is really a problem with the AMC coords how come nobody noticed before?

 

[Kurchian]

But I'm curious about the original question, if there is really a problem with the AMC coords how come nobody noticed before?

Thanks for the education. The AMC coordinates are accurate. I didn't realize that coordinates that have minutes and seconds ( ' and " ) need to be translated to those that don't.

The coordinates listed for the slide departure point on the AMC maps are:
44 08' 16", 71 36' 57.

The coordinates listed for the slide departure point on the excellent ACME map that nartreb listed are:
N 44.13778 W 71.61584

These two coordinates are essentially identical when translated.