Friday, February 14, 2014

Parallel features

parallel features - trails
Example 1 - Parallel trails
Parallel features are any element in the geography and on the map that are similar in shape and the bearing that they follow.

These features can make navigation tricky if you aren't watching our for them. I have had, and heard of, many experiences where the navigator (me) assumed they were on the right trail only to find out that there was an identical feature close by.

In the Who's Your Daddy? 2010 race we were among several teams who spent several hours marching up and down a stream looking for a mandatory CP, never finding it. In the end we all found out that the CP was actually located only a couple hundred meters away on a very similar stream feature.

Several racers in this year's 9-Toe Winter Adventure Race experienced problems when they confused parallel trails running in the same direction.

The best trick to figuring out parallel features is to plan for them before you get to them.

Parallel water features
Example 2 - Parallel water features
Check your route for any features that might be easily confused or that can't be easily identified from another. As you approach these features, makes sure that you pay special attention to your approaches, distances and bearings to ensure that you are at the correct feature.

Features like streams that may not be accurate on the map are particularly difficult since you can't use bends and turns with much confidence to establish position.

Many times it is worth the effort to take a step (or many steps) back away from the feature and approach it again from a different angle to make sure it still makes sense.

In example 2, it would make sense to approach water feature #1 from a lower angle, towards the southern tip, so that you are less likely to miss it and end up at feature #2.

Don't waste a lot of time looking for a CP at the wrong feature. Check for parallel features and reset your approach for best results.