Posted by: Dennis Williams | February 2, 2009

Geocache without a GPS

I’m Old School when it comes to navigating.  That’s one of the chief reasons I like adventure racing.  Geocaching the old school way is a great training tool for adventure racing teams to use to break the monotony of just biking, hiking and paddling together.

Geocaching without a GPS requires a map, a compass, and access to

Get a map of your area at  In my case, my team trains at a city reservoir outside of town, which is home to about 30 geocaches hidden around it and along nearby roads. sells small, medium, and large maps that one can request to be gridded with UTM coordinates.  In my case, I bought the small size map for about $10.

Next, surf over the, put in the zip code for the area targeted by your map and single out some geocaches.  In case you’ve never done geocaching, it works like this:

Someone hides a container somewhere in the landscape.  Typical containers range from military surplus ammo boxes to Altoid tins.  Large containers are filled with various trinkets for the purpose of trading with the finder (treasure), while smaller ones (microcaches) might have just a strip of paper on which you can sign your name. Using a GPS, the hider notes the location of the cache and uploads it to the website. This results in a page like this:

sample page

sample page

The coordinates displayed on the page are in latitude and longitude, but you can use the conversion feature on the page to change them to UTM, the form adventure racers expect.  The seeker peruses the page, loads the coordinates into his/her GPS and lets the GPS navigate them to the cache.  Many carry a few trinkets to trade when seeking a larger cache and certainly a pen to sign the cache log book.

Old School navigators leave the GPS at home.  This was easy for me to do. Two weeks ago, I pulled my Garmen Etrex Legend out of my pack, turned it on, and was chagrined to see the vertical blue line of death appear on the screen.  That’s the third etrex in about six years that died that way.  It will be the last.  GPS is fun, but map and compass is by far much more fun.

This past weekend, my team had about two hours of bike training to do.  The snow and ice had just melted away and the mountain bike trails were muddy.  Not wanting to tear up the trails, we selected six nearby geocaches, pulled the UTM coordinates off the website and headed for the lake. Upon arrival, I pulled out the map, we plotted the coordinates, did some quick route planning, and headed out.  The wind was blowing about 2o mph from the north and the temperature hovered at a nice 55 degrees.  Needless the say, we enjoyed the fact that our course took us to the south first.

Unlike adventure racing, where the checkpoints are bright orange flags, geocaches are often camoflaged and hidden to prevent “muggles” from finding and displacing them.  This makes the challenge that much greater for AR teams going Old School. Unfortunately, the first target cache, entitled “Come and Get Me,” proved unfindable.  According the the logs at, it had been found recently, but, in the time alloted, we didn’t.  We gave ourselves 15 minutes on each cache before heading to the next one in an effort to get as many as possible in our two hour time limit.

We scored on the next three, “Purple People Eater #4,” “100 Miles to Atoka,” and “Holly’s Treasure Chest.”  Purple People Eater and 100 Miles to Atoka were microcaches right along the road.  Holly’s Treasure Chest was a traditional cache consisting of a .30 cal ammo box hidden in the woods.  This was a great cache.  In the races we like best, lots of cp’s are off the trail.  Those are more challenging and require real navigation rather than just speeding along known trails (which gives too much advantage to local teams IMHO).  This cache required us to ditch our bikes and head into the woods looking for a cammoed box.  It took about 10 minutes to find. We signed in and headed out.

Strong head winds on the way back and quick calculation suggested that we needed to head for the cars rather than hunting the last two caches. That OK, they’ll wait for another day. In the end we road two hours, found three geocaches, and remembered several nagivational tricks that we “learned” on previous races.  Tricks like: remember to estimate distance to the next cp or waypoint and have someone keep track of distance along the way; take the harder surface, even if its a bit longer, over a mushy one; don’t get beyond sight distance when fanning out to find a cp in dense brush, etc.

Overall, this old school navigation to geocaches proved a refreshing approach AR training.

Posted by: Dennis Williams | January 18, 2009

Cool Tools from

Plotting points on a map, or extracting their coordinates from one, is a fundamental map skill.  Over the years there have been numerous devices made to make the task easier.

There are several tools available that do this job ranging from rulers to roamers and the most convenient way to get any of them in a wide variety of scales is via  I’ve ordered from them over the past several years and they’ve always been quick to ship and easy to work with.  And no I neither work for them, nor get any compensation from them for praising their good work.

They take credit cards, paypal, etc.

Posted by: Dennis Williams | January 18, 2009

UTM Grid, Roamer, or Slot?

Adventure racing navigators need one of two tools to plot points of their map: a UTM grid or a UTM roamer/corner ruler.  This article describes the differences between the two as well as an improved variation on the theme called the slider from

The Grid

The grid is a small clear plastic device in the required scale that has one square kilometer gridded into 100 meter units like this one.  To use one of these, the navigator finds the appropriate grid square, lays the grid on top of it, runs a pen across the bottom the appropriate easting value and then up to the appropriate northing, slips the grid from beneath the pen and marks the point.

It works fine.  Some people, including myself get a little nervous thinking about the fact that the little box is 100 meters square, but in reality with a tiny bit of interpolation (as in 30 meters is about 1/3 of the way across the little square), these are probably plenty accurate.  Sleepy or stressed folks can sometimes misplot by picking the wrong row or column on the grid though.

The Roamer

The desire for greater accuracy for reducing plotting errors begat the UTM roamer, which is a type of corner ruler.   The roamer has a little ruler on the top (for easting) and right (for northing) sides and a small hole in the top righthand corner large enough for one to poke a pen or pencil tip.  The roamers from Maptools are incremented at te ones level, which is 10 meters on the map. Other roamers I’ve used are marked in quarters (25…50…75 meters).

To use a roamer, one finds the appropriate grid square on the map and lays the roamer over it…with the 9s toward the left and the bottom. Then one slides the roamer to the left until the horizontal scale at the top of the roamer intersects the line on the left hand side of the grid square at the proper easting UTM value and then one slides the roamer down until the the vertical scale intersects the bottom of the grid square at the proper UTM value. The little hole is now over the address and one pokes the tip of one’s pencil tip through the hole, marking the target coordinate.  Cool, huh.

In a way, I love the roamer because I can pretend that it is more accurate and since I find the target address by moving the scale over and down the map, I don’t have an opportunity to miscount columns or rows when I’m tired.  The hole through the corner reduces error by allowing one to mark the map without removing the grid (and thus maybe jostling or forgetting where the point was in the intervening moments…remember after 12 hours you are tired, after 24, you are much tireder and prone to error).

The roamer is a bit slower to use.  I find myself sliding the roamer left, then down, then having to realign the top scale and then check the side scale.  There’s nothing wrong with measuring twice so to mark once, but when one moves the scale one direction it tends to throw things off a bit the other.  That’s frustrating under pressure.

The Slots

Maptools improved on the roamer by cutting a small slot in the vertical scale.  This allows one to the lay the slot tool on the map grid, slide it left to dial in the easting value and then, using the tip of one’s pencil, move up the slot to the appropriate northing value, inserting one’s pencil in the slot and marking.  Notice the improvement…one moves the scale only one direction.  That makes for a faster and more accurate plot. sells two variations of the slot tool that provide four different scales commonly used on maps generated by’s map site. Another variation has 14 different scales. For shorter races in the US (24 hours or less), the mytopo-1 contains the necessary rulers. One needs to have the ones one needs, but too many options on one tool increases the possibility of error.  I’m a convert to this improved tool.

The Downside

No, this is not another tool, but rather a frustration I find using various corner rulers made by maptools.  The small increments (10 meters) on maptools roamers give one a sense of greater accuracy, which is true to a point.  But in realityaccurately resolving down to 10 meters on a 24K scale map is a bit of stretch.  The blot of ink from one’s pen will cover about 30 meters of landscape on the map.  The tradeoff for the perception of accuracy is that the fine gradations on maptools scales are difficult to see since they are so close together…they get kindof blurry when laid atop a busy map. To be fair, maybe that’s just my old, tired eyes.  I’m coming to believe that the perception of certitude provided by these fine gradations is not worth the extra effort to try to distinguish between 77 and 78.

For a different approach, one might draw on the practice of compass manufacturers.  They know that most baseplate compasses aren’t quite accurate enough, nor most users ability see 1 degree increments printed around the 2.5″ diameter bezel to make one degree gradations practicable. Those needing that degree of accuracy use sighting compasses.  Thus, the manufacturers of good baseplate compasses (Silva, Suunto, Brunton), use two degree gradations around the bezel.  That separates out the markings on the compass enough to be useful without compromising real accuracy.  While most people like units of 10, 5 and 1 on scales, units of two on these map tools might be more functional, without compromising real accuracy.

Posted by: Dennis Williams | January 6, 2009

UTM Training Tool

Building on Maria Langer’s Excel random number generator, I created a little program that will randomly generate a set of 15 UTM coordinates to help you practice plotting coordinates on the map.

A good training exercise will require the following tools:

  1. Map with UTM grid on it.  You can order a map of anywhere in the US from  When you create your map, be sure to indicate that you want the UTM grid printed on it.  I like to have Latitude and Longitude ticks printed on it so that they are there (?), but don’t want additional lines to interfere with UTM plotting work.  In all the adventure races in which I’ve competed, the UTM lines are printed on the map and the Lat/Lon lines are not.
  2. 24″ x 36″ sheet of drafting film to lay over the map.  With this,  you can plot coordinates and then erase again and again without messing up the map.
  3. A UTM roamer or grid tool.  You can make your own using the free downloadable pdf files from and a sheet of transparency film for a copier or printer (be sure to get the right kind for what you’re doing, write-on overhead transparency film makes a real mess in a laser printer or copier…don’t ask me how I know).  However, sells all kinds of neat map tools.  I really like the mini-corners and the slots.  They are smaller, simpler (and thus more functional) and less expensive than something like the Brooks-Range All-in-One Map Tool.  That said, if you are doing winter work in avalanche country the Brooks tool has useful slope indexes and the ability to make a handy inclinometer out of it.  If you are navigating on skis, snowshoes or snow machine, buy it, learn to use it and use it.
  4. My handy UTM Point Generator tool.  It’s an excel sheet, so you’ll need Excel installed on your computer.  It will work with Mac or Windows.
  5. a pencil

Once you have all your tools assembled, lay the map out on a table, put the piece of drafting film over it, fire up your computer and open the UTM Point Generator. Fill in the cells in rows 5 and 6 with the correct information from your own map.  The tool will generate 15 points for you to plot on your map.

Work at trying to plot all 15, accurately, in three minutes.

To check your work, go to, enter your UTM coordinates (only one at a time unfortunately), select USGS topo map and click “display.”

When you need a new set of coordinates, just hit command-= or control-= in excel and you’ll get a new set of points for your map.

Special thanks to Maria Langer for designing the foundation for this tool.

Posted by: Dennis Williams | January 5, 2009

Old School Navigation

Navigating in an Adventure Race is “old school” navigation by contemporary standards.  GPS devices are so prevalent in today’s technology that relying on a map with the help of a compass is about as Old School as writing with pen and paper or walking to school uphill in the snow both ways.  That said, skill with map and compass is the skill that separates adults from children and makes it possible to adventure race.

Map and compass navigation is a skill.  It can be learned and with practice mastered.

The purpose of this blog is to promote good map and compass skills to contribute to such extreme sports as adventure racing and orienteering and hobbies such as backpacking, letterboxing, and even the uber-GPS hobby Geocaching, which amazingly can be even more rewarding when practiced without a GPS receiver. Geocaching sans GPS…what a thought!

Early posts in this blog will focus on basic skills and then move on to more advanced techniques as well as theory and instructive accounts of navigational blunders. Readers should feel free to critique and contribute.