Custom USGS Topo Maps

Here in the USA, USGS topo maps are an excellent navigational tool for finding your way in the backcountry. In fact, if I could have only one navigational resource in the wilderness, it would be a good map.

When I say a good map, I mean one that shows enough detail of the terrain to allow you to compare the map to the terrain, and the terrain to the map. After all, if you can do that, your desired direction of travel becomes obvious even without a compass, as in "We need to go to the far right corner of this lake in front of us to find our portage trail to the next lake."

Although you can buy USGS topographic maps directly from the government, you may want to consider spending a few extra bucks for a durable, custom USGS topo map. (See the paragraph and link at the bottom of the page for my recommendation of a good topo map company.)

Advantages of a Custom USGS Topo Map:

1) You get a map that covers the area you need.

Otherwise you might need two or three standard USGS quadrangle maps to show the places where you plan to be.

2) You can get a rugged waterproof map.

If you've ever had to consult a map in the pouring rain, you'll understand the advantage here. I know some people use plastic freezer bags to encase their maps, but it's amazing how often you have to open the bag in the rain just to refold the map to be able to see the area you need to see. It doesn't take long for a regular paper map to disintegrate once it gets wet.

3) You can get a map of your preferred scale.

The popular USGS 7.5 quad maps (so named because they depict a quadrangular area 7.5 degrees of latitude x 7.5 degrees of longitude) use a 1:24,000 scale in which one inch on the map equals 24,000 inches, or two thousand feet on the ground. Similarly, one centimeter on the map equals 240 meters on the ground.

When customizing, some people prefer a 1:25,000 scale in which one centimeter on the map equals 250 meters on the terrain. Using the 1:25,000 scale, it's convenient that four centimeters on the map equal exactly one kilometer on the ground.

4) You can add the UTM grid to your map.

Many USGS maps that come straight from USGS have UTM grid tick marks in the margin, but don't actually have the grid drawn in, meaning you'll have to resort to using a pencil and a long straight-edge to painstakingly do it yourself.

5) You can even have the lat/long grid drawn on your map's face if you wish.

I'm not sure why anyone would want to do this, but it is an option.

6) You can specify which datum you want your map to be based on.

A datum is an originating point on which grid lines are based. In the US, the two datums pertinent to USGS topo maps are the North American Datum of 1927 (NAD27) and the North American Datum of 1983 (NAD83). The latter, according to my understanding, is interchangeable with the World Geodetic Survey of 1984 (WGS84).

When comparing grid coordinates with others who have maps based on a different datum, the exact same coordinate might differ by 200 meters or more. If you're part of a group, you may want to order a map based on the datum your group uses. That way, everyone's coordinates will all signify the same place on the map.

Where to Get Good Custom Topo Maps

For quality custom USGS topo maps, I like MyTopo.com. Based in the Big Sky Country of Billings, Montana, these folks know topo maps. And they offer the custom features discussed above. You can even get different sizes.

In business since 1988, they have an easy web-based five-step ordering process. Got questions? Paige at MyTopo is good at answering them. Call her at MyTopo 1-877-587-9004.

If you're like me, once you discover these maps, you'll much prefer them to the regular old off-the-shelf USGS 7.5 quads.

Good luck. And STAY FOUND.