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What's this "Orienteering Map" thing?

Racers will be using a new tool to help navigate this year at Wilderness Traverse: an orienteering map. So what the heck does that mean? A map is a map is a map, no? Well, mostly...but there are several key differences between orienteering maps and the regular topographical maps they are used to.

Below is the "Georgian Nordic Map" from the racers' package. It may look like just a colourful version of a topo map, but there are some very important differences that racers will need to take into account if they want to use it effectively. I have highlighted those with orange markings. The most obvious difference is the scale. Instead of 1:50,000 this map is 1:15,000, meaning it is like zooming in on a topo map by a factor of more than 300%. At first glance that would seem to be a huge advantage: having more details should make navigation easier, right? Well...yes and no.

The next 2 things to notice are the contour interval and the distance scale. On a 50k topo the contour interval is 10 metres, while on this orienteering map they are only 2.5 metres. What this means is that much smaller and more subtle elevation features are shown on this map. A section that might be completely featureless on a 50k topo could be full of small hills, knolls, and depressions on an orienteering map. This allows Bob and Barb to place CPs on or near features that are much more subtle than racers are used to.

The distance scale is also greatly zoomed in compared to what racers are used to. On a 50k topo the UTM grid lines are 1 km apart: on this orienteering map the grid lines are only 0.25 kms (250 metres) apart. Racers will tend to overshoot whatever they are aiming for unless they pay careful attention to all the extra details and stay in touch with the map as they move.

To really see how dramatic the differences are, here is the same area from the topo map. Note that it does NOT align with the UTM grid lines...

Speaking of grid lines: the ones on orienteering maps are aligned to magnetic North, not True North. I've circled the big "N Magnetic North" icon at the top right of the map. This is critically important, because the topo maps - which are aligned to True North - need racers to correct their compasses to account for a 10.5 degree West declination. If they keep that setting on their compass for this map, they will be consistently travelling 10.5 degrees too far to their right. They need to reset their compasses to 0 declination (and then remember to reset them again to 10.5 West when switching to the topo maps) or have a separate uncorrected compass for use with this map.

You've likely noticed that there are lots of colours and symbols being used on the orienteering map compared to the topo map. Those are not to make it pretty, but rather to show details: all of those symbols and colours mean very specific things. This is why orienteering maps come with a legend. This is basically a list of the standardised symbols and colours used and what they all mean. The legend for this map is shown below,

This race will have a quick orienteering Prologue off the Start. This is a short but potentially tricky trekking leg that will separate the teams before thy get onto their bikes for Leg #1. The Prologue is shown below. Teams will start in the triangle and must collect CPs A, B, and C in any order before returning to the start triangle to pick up their bikes and riding out to CP1, CP2, and the highway crossing exiting the left edge of this map en route to CP3.

The control description for the prologue CPs are as follows: A - small hilltop B - small hilltop C - trail between small hilltops

The only routes that don't involve any backtracking are "A-B-C" and "C-B-A", so those are the obvious choices that most if not all teams will decide on. I've highlighted a possibly impassable slope with a red oval: whenever you see contour lines packed very closely together, it means that the slope there is very steep. There are a few of these scattered around this Prologue.

I've also picked out what I think to be the tricky crux of the Prologue: CP A. Attacking it from the Start (from the North) is difficult because you have to cross almost 300 metres of essentially level, featureless forest and try to hit a small, narrow hilltop feature. The safest way to attack A is from below and to the West, where you can follow a re-entrant (a shallow gully going up the slope) up to a point between the two summits, which will put you right beside the control. As such, I think most teams will opt for the "C-B-A" route option.

Finally, racers will need to be aware that there is only 1 way off this map. It is shown with "To CP 3" on the left edge of the map, surrounded by "out of bounds" areas. I have highlighted it with an orange arrow. I have also circled and highlighted the only crossing of the waterway between CP2 and the Exit, so teams will have to treat this like a mandatory waypoint. Unless they want to wade/swim their bikes.


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