[at-l] re: Pittsburg(h)

[wdlists at optonline.net (Walt Daniels)]

> 
> 
> >>>Didn't DelDoc do this by GPS before his death last year?
> >>>
> >>>      
> >>>
> What happened to the raw data?
> 
> -Ryan
> 
All the raw (and corrected) data is in ATC's GIS system. Unfortunately
DelDoc did not finish the whole second pass. That was completed this summer.
It takes a while to do all the corrections. When they are done, it will be
published. The older data is on the web or at least was before the change to
the new website. I have it. However it had many gaps where there was missing
data, which was filled in with data from existing maps. I walked my sections
with DelDoc on the first trip, and we lost all satelites on about the only
section where I was unsure of the data. So that data is as bogus as the
older maps in some places. The second pass data should all be good to about
one meter or better. This accuracy is obtained by setting up a secondary GPS
at fixed points within a few 10s of kilometers of the trail and doing
differential correction from it. Much better than relying on the national
differential corection data which is frequently 100 or more kilometers away
from the trail.