Sunday, June 08, 2014

Mapmaking

There are little-marked trails in the woods near my house.  They are used primarily by snow machines in winter, though I can see occasional footprints and tire prints when I am walking back there spring and summer.  A neighbor who grooms the trails tells me he doesn't know of any maps of them.  I resolved to make one for my own enjoyment and safety, to know where I am as the seasons change or I decide to explore different sections.

I didn't think it would be that hard.  I can make a decent road map to give directions, and think of myself as having a good, though not exceptional sense-of-direction. Also, the territory in question is only a couple of square miles tops, so I would have trouble getting deeply lost in any way. (I am guessing there are more than 5 miles of trail, though.  Maybe 10 or more. They interconnect quite a bit.)  I discuss a lot of the issues in my 2011 series on Wayfinding. (Has it been that long?)

Yet I find I go wrong almost immediately.  The cues are ambiguous, undermining one's confidence that the memorised links are valid: 643 steps generally WNW with some winding back and forth.  So say, less than 600 as the crow flies, call it a quarter mile.  Then almost north for 200 steps to the stream, then left onto that very winding path up to the ridge. I figure that is close to NW, maybe a little west of that, almost another quarter mile.  That leads us to -- hell, a stone wall about 70 degrees off from where it should be.  Something's gone wrong here.  I can't be crossing the stone wall at this angle. It shouldn't be near here, either.

Half a mile from the start and I'm already uncertain how to draw the path I have just trod.  Walking 200 yards up the ridge, so that I can now look back over the territory, and even into the neighborhood, does not resolve this.  Things are not where they should be.

I am slowly working it out.  I am not bringing paper and pen, trying to do this by memory.  I try different trails to come in from a different direction.  I hike earlier or later, to be more sure what direction the sun is in.  I am making corrections as well.  The central stone wall I have been using as the spine of my calculations actually turns 15 degrees S just as it goes out of my sight at the very beginning.  That 15 degrees, plus my "70 degrees off" above, is 85 degrees, suggesting that yes! this is a different stone wall, which meets the other at a right angle deep in the underbrush.  I was right the first time...except how can that trail meet the other so quickly then? That would make two sides of a triangle added together shorter than the third.  That can't be.  Where the hell am I?

I could bring in a GPS, things to write with, and the USGS or SPNHF maps, I suppose.  Yet I would like to have the ancestral experience instead. 

I'm not very good at this.

2 comments:

sykes.1 said...

If you want to do this right, go get a USGS topo map (there are several scales) and an engineer's compass. Just mark the trails on the topo map and use the copass to get the headings.

Assistant Village Idiot said...

I have decided I do need a compass. The stone walls could be excellent landmarks if I had them right. USGS topos have the elevation advantage as well.

But I haven't wanted to bring paper into the woods to work this out for some reason. I have arbitrarily designated that as cheating. There is nothing sensible about that, but there it is.

Sponge-headed scienceman should be of considerable assistance.