Re: Source Topological Maps for USA?

Gary S. wrote:
On Mon, 24 Apr 2006 09:12:05 -0400, VtSkier <VtSkier@xxxxxxxxxx>
wrote:


Delorme's topo maps are NOT USGS. I don't know what the
base is, but compared to USGS, they are horribly
inaccurate. The best you can say for them is that they
are somewhat useful in your car and don't cost very much.

I believe the digital versions are just as bad as the
paper versions.

Other than the National Geographic version of USGS maps
in digital format (which are great) the only other digital
maps I have any experience with are Garmin MapSource which
are compatible with my GPS receiver and in that mode are
quite useful, but not very good as stand-alone maps.


Different map products have different sources, even from the same
publisher.

The DeLorme 3D Topo Quad, the NG TOPO!, and the MapTech Terrain
Navigator all start with scans of the 7.5 minute USGS maps, and
includes some version of the digital elevation model (DEM). Maptech is
my favorite of the bunch, based on features and interface.

Downside, of course, is that the newest USGS maps are based on 1980s
data and aerial photos. Not an issue for most geographic features, but
some water features and many manmade features have changed.

For the DeLorme state atlas series, they have developed their own data
for that.

We were all much happier with maps before having a GPS would show us
they were inaccurate.

I guess it's the State Atlas Series that I'm having so much
trouble with. Here is one of my favorites:

Heading to Killington you go up East Mountain Road from Route 4
near Skyeship Base. This to go to Bear Mountain. Follow East
Mountain Road as it winds up the hill to just before the Great
Eastern Bridge and turn left onto Bear Mountain Road. Just before
the Bear Mountain Parking lot is the access for Sunrise Condos and
Top Ridge homes. It's a LEFT turn and has a bunch of roads to
access the homes and condos.

Now find all of this in DeLorme's Vt State Atlas. Follow the
roads as I describe on the map until you get to the access
for Sunrise/Top Ridge. The map has it as a RIGHT turn and all
of the condo/homesite roads to the north of Bear when in
reality all of it is to the south of Bear.

This is just one. When the state atlas first came out, around
the mid-80's I believe, I was so appalled at this and other
flagrant errors in an area that I know well that I wrote and
offered to "beta-test" the maps for the next edition with
examples of errors in the area that I knew and suggested that
DeLorme get other people in other areas to do the same. I
never heard from them even though I goaded them a bit by
writing another letter when the second edition came out and
there were NO changes in the areas that I had made notes
about in the past. This is when I started dump on DeLorme
whenever I could.

So what you are saying is that DeLorme's digital topos have
some basis in reality? That's great as I have them loaded on
my laptop and just haven't gotten to cruise around them yet.

Actually, my digital USGS maps are quite accurate if not
completely up to date (I have one which I think is current
for 1947 or some such). When I put in a waypoint and go
there, everything is pretty much as it is on the map.
Also, USGS maps may be listed as up to date for, oh say,
1997. But there is culture that you KNOW was there before
1997, like almost all of the trails at Killington, yet the
map shows only K-peak, snowdon, rams and snowshed. No Skye
and no Bear and snowdon is shown with two short lifts.
The original Skye Peak Gondola was built in about 1972, so
there is a little lack of care for currency even with USGS.
.

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