Saturday, October 22, 2011

The More You Know, the More You Topo

I'm very excited.  I recently made a wonderful discovery.  I'm assuming, because it was news to me, that it will be news to at least some of you.  I hope that doesn't come across as arrogance.  Free Topographic Maps!  If that statement alone doesn't excite you, you may wish to skip the rest of this post.  On the other hand, you may want to continue reading.

Topographic maps look funny, but that's because they tell you something other maps don't.  The "squiggly lines" with which these maps are covered denote the elevation at any given point on the ground.  How much change each pair of lines shows will be indicated on the map's legend. Topographic maps are useful to outdoorsfolk for many reasons, but my favorite thing about them is that they tell you where the water is (the USGS calls this "hydrographic information").  One of the central parts of my camping philosophy is that you should always camp near running water (streams, not faucets) if possible.  This keeps you from having to carry 4 gallons of water for an overnight trip with your dog.  But how do you know whether there will be running water near a campsite you've never been to?  You'll know if you just take a look at a topographic map.  What follows is a run-through of the process I now use to scout out potential camping areas.

First, you need to find a basic map of the area you'll be hiking/camping in.  Where will you park your car?  What direction will you go?  You'll need to have at least tentative answers to those questions before you look for a topo map.  Let's say I've been told that the Uwharrie National Forest is especially beautiful north of State Route 109.  I need to find a map of some kind to tell me where the trailhead, or at least a place to park, might be.  I found the one below on a website maintained by Boy Scout Troop 274.
I can see by looking at this map that there is parking for the Uwharrie Recreational Trail where it crosses SR 109.  I'll use that info when looking for a topo map.  To find one, I'll go to store.usgs.gov and use their map locator.  The USGS store homepage is kind of cluttered, and the URL for the map locator keeps changing, so here's a picture of the link you're looking for.
Once you open the map locator, you'll be able to navigate a basic, non-topo map of the United States.  If it looks a lot like Google Maps, that's because it is.  You start by default in "Navigate" mode, which allows you to zero in on a particular portion of the country.  In the screen shot below, I've zoomed in on the portion of the Uwharrie National Forest I intend to examine.
To find a trailhead not marked on Google Maps, I could potentially use the coordinates displayed in the lower right-hand corner of the "Navigate" screen.  Coordinates won't help in this case, though, because they are not displayed on the trail map I found.  Oh well.  Noticing intersections and curves in the road helps.  The Uwharrie Trail is not marked at all on this map, but I know that the trailhead is on 109 just Northwest of 1147 and just southeast of where 109 curves to the North.  With the "Navigate" map centered roughly where the trailhead should be, I click (to the right of the map) to select "Mark Points" mode.
The black lines denote the borders between downloadable topographic maps.  To select the one containing my trailhead (and the supposedly beautiful country to the North of it), I click on the map to place a marker.
Clicking on the marker I have just placed opens a dialog box with the option to download (for free) the map of the area inside that black rectangle.  "View" lets you look at a thumbnail image of the topo map, but not a full-size version.  Download the map with "US Topo" in the name.
Once you've downloaded the map you can peruse it at your leisure.  It's quite large (full size is 29"x22") and extremely detailed.  Once again, recognizing intersections and curves in the road helps here.  The trail is not marked on the topo map, but by comparing the topo map to the trail map the Boy Scouts posted I can see where I'll be going.  As you can see, I'll cross three creeks in the first few miles of the trail.
As long as I can build a fire and boil water to purify it, I'm set!  Just in case the available wood is all wet, I'll probably bring my portable isobutane stove.  I'll bring at most a half-gallon of water for the hike in, and camp next to a creek.  Thanks to the USGS, I'll even know what the name of the creek is!

Hope this helps.  Stay hardy!

P.S.  Although the USGS topo maps have been updated many times, they sometimes still label service roads that haven't been in use since 1940 or so as "local routes."  If a road is not marked on  map, it's probably not there.  However, some roads that are marked on a topo map may no longer even be recognizable as roads.  Many trails marked "4 wheel drive" on the map legend have been closed to vehicular traffic for years.

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