[pct-l] PCT Map Programs Redux

[bharve at dslextreme.com (Bruce Harvey)]

I use TOPO! a fair bit and intend to buy a GPS receiver, so am interested in
the disagreements you found between the two on middle sister.  A few
questions:
Were you using TOPO! and GPS set to the same datum?
Was your GPS receiver in 2D mode at the time of the read on middle sister?
Does your GPS convert from ellipsoid elevation (distance from center of the
earth) to geoid elevation (distance from mean sea level)?  Most, but not
all, GPS receivers do.

Last question: Do you (or anyone out there) know of a way to find the field
check date and edit date of  particular USGS quads you are working within as
you use TOPO! ?
----- Original Message ----- 
From: "David" <david@dalbey.org>
To: "'pctl (E-mail)'" <pct-l@mailman.backcountry.net>
Sent: Monday, January 26, 2004 9:32 PM
Subject: RE: [pct-l] PCT Map Programs Redux


> I have the National Geographic maps, (powered by TOPO!), for Oregon as
well
> as a book entitled GPS Waypoints:  Oregon.  Last summer I climbed middle
> sister & entered the summit from both into my GPS.  The books coordinates
> were spot on.  The National Geographic maps, (powered by TOPO!), had me
> about 200 horizontal feet and 800 vertical feet off!
>
> I used the National Geographic maps, (powered by TOPO!), for a 4 day hike
in
> the diamond peak area and was happy with them.  I guess I'm just saying I
> wouldn't use it to find a spring or other small object, but for lakes and
> trail junctions it was fine.
>
> David
> david@dalbey.org
>
>   :-----Original Message-----
>   :From: pct-l-bounces@mailman.backcountry.net [mailto:pct-l-
>   :bounces@mailman.backcountry.net] On Behalf Of Judson Brown
>   :Sent: Monday, January 26, 2004 6:50 PM
>   :To: pctl (E-mail)
>   :Subject: RE: [pct-l] PCT Map Programs Redux
>   :
>   :I have used both TOPO! and Mapquest, and prefer the former
significantly.
>   :This is mostly to the stupid design on the route
tracing/mileage/profile
>   :maker thingy on the Mapquest. TOPO!'s is much less of a pain in the ass
>   :to
>   :use. Mapquest is also more prone to wildly inaccurate elevation
readings.
>   :For example, I'll be pointing at a definite elevation listed on the
map-
>   :a
>   :summit, lake, etc.- and the program will state and elevation which is
>   :seldom
>   :accurate, and often up to 200' off.
>   :
>   :Judson
>
>
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