[Cdt-l] quad maps unnecessary

Jonathan Ley jonathan at phlumf.com
Mon Jan 27 14:12:12 CST 2014

I was just going to point that out - my maps are just the USGS 1:24000
"quads" with CDT-specific info overlaid onto them. So, when you print them,
they come out to ~1:60,000 on a 8.5 x 11 sheet of paper. Of course some of
the fine detail is hard to read, but it's all there. Plus, these are all
spliced-together, so they're a bit more efficiently cropped.


The original USGS quad sheets are quite large. They're neat to look at, but
not quite so practical in the field. (In addition, murphy's law dictates
that whatever location you're interested in will be right on the corner of a
map, meaning you need to line-up 4 of them). Anyway, you can download them
from the USGS - they're open-source items. so, if you have access to a
large-format printer, there you go. 


However, my understanding is that the USGS is no longer updating the
traditional quads (also called 7.5  minute maps). Instead, they're focusing
on providing layered digital mapping information to fulfill their mission. I
think they made this change about 10 years ago, but some of the quads are
quite a bit older. I can understand why the USGS would do this, but it still
sucks for those who aren't doing professional GIS mapping. and the old quads
get more and more dated. The land might not change, but some things do - the
shapes of glaciers and forests. And there is a lot of useful man-made
information on the quads - primarily roads & trails. It might possible to
"reconstruct a quad" with the latest digital data & the right software
tools. I haven't really looked into it, but I bet someone somewhere has done
a blog post about it J Anyway, that's all just my understanding of the
situation. Not sure I'm 100% correct on this.





From: cdt-l-bounces at backcountry.net [mailto:cdt-l-bounces at backcountry.net]
On Behalf Of blisterfree at yahoo.com
Sent: Monday, January 27, 2014 10:21 AM
To: Continental Divide Trail
Subject: [Cdt-l] quad maps unnecessary


USGS 1:24000 isn't about the specific scale so much as the level of detail
depicted in the series. And the detail isn't so much about man made
features, which can change or have inaccuracies, as it is the topography and
hydrology, which are more or less static and the main focus of navigation. I
believe Jonathan's maps are portions of USGS 1:24000 digitized maps at a
sub-40% scale reduction. Of course what makes them work is all of the work
he puts into them to show the route options and suggestions for travel. The
fine map detail and the CDT-specific add-ins work synergistically to make
the product the wonder to behold that it is. 


Sent from Yahoo! Mail for iPhone


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