[cdt-l] Topo USA vs. TOPO!

[cdt-l@mailman.backcountry.net (Ginny & Jim Owen)]

Earlier today this was posted on pct-l.  I'm posting it here because not 
everyone is on both lists - and I think it may be of interest to those who 
are doing their own "map-making".  While I have no personal interest, nor 
any real basis for an opinion about the subject, I believe it probably 
applies to the CDT as well as to the PCT.  I'm posting it with prior 
permission of the author.

Some of you will get it for the second time - but I'm sure you know where 
the delete key is located  :-)

Walk softly,
Jim

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Date: Mon, 14 May 2001 16:57:27 -0700
From: John Mertes <jmertes@gte.net>
To: P C T List <pct-l@backcountry.net>
Subject: [pct-l] Topo USA vs. TOPO!

    I've compared National Geographic's TOPO! (formerly owned by
Wildflower) with DeLorme's Topo USA 3.0 on planning and recapping my
recent 3-day / 21.3 mile backpack. My opinion based on this comparison
is that Topo USA is almost worthless or worse for backpacking. OTOH,
TOPO! seems quite good.

    The main problem with Topo USA 3.0 is that the route of the PCT is
grossly wrong. We started at the trailhead off of CA 44, it doesn't have
this trailhead. It shows the PCT traversing northward down the Hat Creek
Rim escarpment and then steeply back up and along the north edge of Lost
Creek canyon. The PCT really goes northward on top of the escarpment and

then eastward along the south side of Lost Creek canyon before turning
back west along the north side of that canyon. The trail is shown about
1/2 mile west of where it actually is and depicts approximately a 900
foot elevation loss and regain that in fact doesn't exist.

    Further along just above FSR 22, the PCT bows to the west while Topo
USA shows it going straight northward; at the maximum there is again
about a 1/2 mile difference. Also FSR 22 is not even identified as such.

    And near the end of our trip, Topo USA misses the switchbacks down
the escarpment and has the route about 1/2 mile from where it should be.

    To me, these errors are enough to make Topo USA worse then useless
for planning and navigating since one would have bad directions and a
false idea of altitude gain and loss.

`    Topo!, OTOH, is quite accurate even though it is an older product.
My GPS track of the PCT shows some minor deviations from the PCT as show
in TOPO!. The deviations may be small enough to be due to GPS error or
to slight misrepresentation of the actual route. However I found the
waypoints I set based on TOPO! to be accurate to within .05 mile.

    I tried uploading my waypoint set from Topo USA to my Garmin 12XL
GPS. The process is more difficult and involved than with TOPO!; and
Topo USA added an extra digit or two to my waypoint numbers.

    Topo USA seems to me to be harder to use as well as worse than
useless for backpacking. I plan to return my copy for credit.

John Mertes

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