Nav hints from Jim

Well, there were about 5 teams representing out at the orienteering clinic last sunday.  For those that missed it and are new to the whole navigation thing, Jim G. has written up some 'how to' hints that will help you get through the race.  If you're just beginning, focus on points 1 and 2 and don't worry about number 3 for now.  Likely there won't be a need for 'precision' nav in this race - but solid 'rough nav' will help you go fast and more importantly, in the right general direction.

Jim here with a few basic tips for navigating during SPAR (and future adventure races).

For ease of reference, assume you are at control point 1 (CP1) and now want to go to CP2. And remember North is always at the top of the map, so these instructions assume you are holding the map flat with the top (North) away from you.

1. Should I stay or go? The longer you stand at CP1, the more likely you will give away its location to a team behind you. On the other hand, if you race off without a clear plan for getting to CP2, you may waste precious time by going the wrong way. And, after you check the map, don’t forget to check the clue for CP2—it can’t help you if you don’t read it.

2. Can I use “rough” navigation? If CP2 is fairly close, you may save time by “eyeballing” the map rather than doing precision compass work. If the map shows CP2 straight left of CP1, then in the field CP2 is basically West from CP1. A quick check of your compass needle, which points North in the field, will tell you which way is West, and you can head right out on that course toward CP2. When the distance is short, varying a few degrees off course usually won’t hinder finding the CP. 

Rough navigation can also save time when CP2 is not close to CP1, but it is close to an obvious landmark (like a trail, road, river, etc.). As above, eyeball the direction from CP1 to the feature, check your compass needle to find the right direction in the field, and take off running in that direction. When you find the landmark in the field, slow down and focus your search on an aspect of the landmark close to CP2 (like a sharp bend in theriver, or the SE corner of a field).

3. Should I use “precision” navigation? If CP2 is not close to CP1 or to an obvious landmark, you will probably need more precise compass work. This is not difficult, but it does take more time than rough navigation.

Your first step, just like in the rough navigation example, is to determine on the map the direction from CP1 to CP2. That direction is called a “bearing.” To take a bearing from the map, put the rear corner of your compass on CP1, and turn the entire compass (not the degree dial) so that the compass’ front corner points at CP2 (or crosses it). Thus, if you drew a line along the edge of the compass’ baseplate from rear to front, it would start at CP1 and run towards (or though) CP2. Now, holding the compass in place, rotate its degree ring until the 2 parallel lines on the compass face indicating North (the “gate”) are toward the top of the map, and the vertical lines in the compass capsule are parallel with the map’s left and right margins (ignore the compass needle for this step). The bearing is the number where the direction of travel arrow intersects the degree dial. If our eyeball example above was accurate, then the bearing should be 270.

The next step is to translate the map bearing to a field bearing. Leaving the compass bearing as it was from the last step (so it’s still showing 270), hold the compass flat in front of you, and turn your entire body until the compass needle is “boxed” in the gate (so the needle falls between the 2 parallel gate lines). You should now be facing 270, the direction to CP2 (the compass’ direction of travel arrow will also be pointing that way). Pick a recognizable object in your line of travel (a crooked tree, group of bushes, bare spot, etc.) and walk to it. Then take another field bearing the same way, pick a new object, and go to it. Repeat until you reach CP2.

4. What route should I use? The last example described taking and following a straight bearing from CP1 to CP2. In reality, while a straight line may be the shortest distance between two CPs, it is not always the fastest or the smartest route. Staying on a trail or road for a longer distance will often take less time and less energy than taking a “shortcut” that bushwhacks up and down a hill or wades through a field of long grass. If you use the process above of picking a recognizable object along your bearing, you are not forced to follow the bearing strictly; you can take an easier course to the object, knowing once you arrive at the object you are back on the bearing. Alternatively, maybe you don’t need a bearing from CP1 at all. For example, maybe you already know how to get from CP1 to a road that will take you to the general area where CP2 is. But if CP2 is in the forest some distance from the road, you will need a bearing—taken not from CP1, but from an “attack point” on the road. An attack point is simply a recognizable feature from which you can take a bearing on the map and transfer it to the field. For example, if the map shows an intersection in the road not far from CP2, you could take a map bearing from the intersection to CP2, go to the intersection and head into the forest following the map bearing.

5. Orienting the map to the field. This just means you line up north on the map (the top) with north in the field. This is not a necessary step, but it can be useful for both rough and precision navigation because it helps you translate the map’s landmarks to those you see in the field.

Turn your compass dial to 0 degrees (due North). Put the compass on the map with the direction of travel arrow pointing up. Hold the map and compass flat in front of you, and turn your whole body until the compass needle is boxed in the gate. Now the map is “oriented” to north, so when you look to your left you will see the landmarks the map shows are west of your location


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