[pct-l] Hey all - DeLorme Maps, etc

[matt maxon]

While I am not a fan of Delorme, I feel I have to jump to their defense.

Delorme, National Geographic, MapTech, and other "publishers", don't 
actually produce the maps they "publish". They are "packagers", or value 
added service providers.

The United States Geological Survey (USGS) is the publisher of the maps.

To the PCT as shown on the maps. While the USGS is responsible for 
publishing the map and it's accuracy, with constitutionally mandated 
accuracy , they gather data from various sources to create the maps . In 
the case of the Pacific Crest National Scenic Trail (PCT) the trail is 
from the lead agency for the PCT , United States Department of 
Agriculture, Forest Service (Forest Service, or FS). But here again it 
is collected from various sources, but the BLM, State agencies are the 2 
main ones.

The trail shown on many maps is the original 1974 (?) trail published in 
the Federal register, which in may cases was just that a line on a map. 
Where the PCT used existing trail systems the accuracy was ok, where 
they where breaking new ground it was a general location at best. It in 
no way reflected what was actually on the ground, I personally feel it 
should be in purple to indicate it is preliminary unverified data, or in 
some other way noted as such

This created problems for the PCTA maintainers here in Southern 
California PCTA Region 1, as the PCT broke lots of new ground. That was 
the impetus for me to survey the trail using my now varied collection of 
GPS units .The poor quality of data on the maps presented a myriad of 
problems in planning, reporting, logistics, and dispatching of trail crews.

When if ever the trail will be shown with any accuracy is anybodies  
guess, my guess is never.

My data is freely available to anyone who is using it for non-commercial 
purposes, it cost me a great deal in not only time and effort, but 
$$$$$$. I got something out of it too. I got to know the trail on a 
level not many people do have or really would want to have. I also got 
an education in GPS, GIS, cartography, data management, and to a lesser 
extent publishing in general. Probably other ways I have yet to fathom.

I haven't finished and hope one day to complete the entire trail with 
the level of accuracy I have in Southern California, now that I have 
honed my data collection skills,. I am certain there will be other 
lessons to be learned up the trail , hopefully I'll be up to the challenge.

Regards
Trail90

stillroaming wrote:
> I've compared 3 data sources on the PCT sections A, B, C.
>
> The first data source was DeLorme and I compared it against the data I 
> personally collected with a gps. The traces weren't even close, 2-3 miles 
> off in some instances and rarely overlapping each other.
>
> I then compared those 2 sources to the Forest Service pct_02 data. The 
> DeLorme and pct_02 data, again, were waaay off. Then I compared the data I 
> collected with the pct_02 data and they were right on top of each other, 
> with minor deviations that I'll blame on my gps (in)accuracy.
>
> My conclusions? Don't use the DeLorme data where it might count. Better yet, 
> why would you use a gps at all on the PCT? :)
>
> And even better yet, you're using the guidebooks anyways, so my post is 
> moot. Please disregard. ;)
>
> Scott
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