Early in the morning the hunter hiked north from camp to Mahogany Butte. With an hour of light left it was time to return. He had his day pack with map and compass and he knew how to use them. But he didn’t have a GPS. The wooded terrain around him didn’t lend itself to triangulation with a compass. So what was he to do? If he was paying attention to his navigation before leaving camp at dawn he was all set. All he needed to do was to return to the base line.
Returning to a baseline is a pretty straight forward concept. The idea is that you leave camp from a known location and strike out in a specific direction such as North, or 000°. When it is time to return aim to the left or right of camp (like 165°T), hit the logging road camp is on and turn right. That is the concept but there is a bit more to it.
Let’s go over the tools you need and the process of how it works in more detail.
My recommendation is to first purchase a reliable compass that can be adjusted for declination. A solid compass made by Suunto, Brunton (the 8010G) and Silva (the Ranger pictured above) are great choices. Learn how to adjust the compass for the declination or your location. (Note: declination is the difference between true north and magnetic north. Declination for your area can be found at www.magnetic-declination.com. ) Note that some of the inexpensive compasses will indicate that it has declination marking/grid on the packaging. You want a compass that can be mechanically adjusted.
If the sales clerks eyes glaze over you are in the wrong store.
The essence of back country navigation is to keep it simple. If you are new to compass navigation, having a compass that can be adjusted keeps things simple. Though the red magnetic needle still points to magnetic north, the rotating dial (that has been adjusted) now provides information in degrees true. A compass that is aligned to degrees true now works well with the traditional topographic map that is oriented to degrees true as well. Take a look at June Fleming’s book Staying Found or visit www.landnavigation.org.
The next tool is your map. USGS topographic maps and National Geographic maps of the major national parks are great examples of what works well in the backcountry. Let’s leave the Gazetteer or AAA roadmap at home. I’ll carry a copy of the Forest Service or BLM map of the area too.
On the map, locate what will be the base line. A baseline can be a road, river or trail. Key to the selection is that you want a baseline of sufficient length. It must also be obvious when you approach the baseline; it needs to be distinct.
For example, in the case of the hunter mentioned above, he would have potentially tragic consequences if he over shot his base line and just kept on walking.
So let’s take a look at a map and develop a baseline.
The red arrows on the map (to the left) point to a road. This road travels in a general direction of Northwest – Southeast. Further, the road travels for many miles in either direction.
Think of the baseline as a geographic boundary. The baseline is designed to keep you within a specific area.
The map directly above is of the same location but it has been zoomed in for clarity.
Notice the location of camp to the east of the baseline; the road.
Also notice that the planned destination has been added. The destination is to the Northeast of camp. Roughly the destination bears 070°T (degrees true) from Camp.
The intent now is to travel from Camp to Destination.
Remember that the compass must be adjusted for declination. In this location the declination is 16° east (below.)
At this point, adjust the compass such that the adjustable outer dial is rotated to 070°T (T for degrees true) and is aligned with the direction of travel arrow or index line. After the dial is adjusted turn your body so that the magnetic needle rotates on top of the red baseplate needle (engraved into the plastic of the baseplate (below.)
Now proceed towards the destination. You have the option of looking down range in the direction of “Destination” or monitoring the compass the entire length of the hike; that is a bit tedious.
Note that in a hike such as this you are going to the general location of the area you want to be in. If you decide to go to a specific, defined location you must triangulate to fix your position, use pace count or use a GPS.
Observe how the topographic contour lines (brown lines) in the center of the image are far apart which means that the land is somewhat flat. The lines in the bottom left of the image begin to merge indicating a hill.
It is the return hike to camp that will take advantage of the baseline.
Rather than trying to go directly back to camp offset the direction of travel to the south. Roughly one will travel in a direction of 230°T.
The key point is that the hiker will knowingly head south of camp to intersect the baseline.
Of course the option of going north of camp on a direction of 280°T could be considered too.
Upon arriving at the baseline turn right and follow the road back to camp.
That’s it.
Remember the cautions mentioned earlier:
- The baseline must be of sufficient length.
- The baseline must be obvious when you reach it. If you are in an area of multiple trails or logging road think carefully if your choice is going to work for you.
Follow Us!