Map, Compass & GPS

Map, Compass & GPS
Wild flowers along Fall Creek on the way to the Green Lakes - Oregon

Friday, November 28, 2014

Baseline Compass Navigation

Baseline navigation is a fundamental map and compass skill.  It is a process of using terrain and land features to the hiker’s advantage.

Outdoor Quest image
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.

The essence of backcountry navigation is to keep it simple.  If you are new to compass navigation, having a compass that can be adjusted for declination 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

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 road map at home.)  I’ll also carry a copy of the Forest Service or BLM map because they will provide a broad overview of the area.

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.  Do not overshoot the baseline and keep on walking.

So let’s take a look at a map and develop a baseline.

The red arrows on the map above 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 the hiker  within a specific area.

The map 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.  Notice that the planned destination has been added.  The destination is to the Northeast of camp.  Roughly the destination bears 070°T (T for degrees true) from Camp.

The intent now is to travel from Camp to Destination.

Outdoor Quest Image
At this point, adjust the compass such that the adjustable outer dial is rotated to 070°T and is aligned with the direction of travel arrow or index line.  

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 with a compass to fix your position, use pace count or use a GPS.

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:

  1. The baseline must be of sufficient length.
  2. 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.

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