Orienteering

There’s one of those map overlays, which we discussed in the comments to the last post on topic. 

It turns out that I do know how to do this stuff, which was gratifying to learn. 


5 comments:

raven said...

Ah! Now I see- it is the size of one grid, grid marked incrementally, with degrees marked also.
Why is it marked right to left for distance?

Anonymous said...

Those grids that I’ve seen are marked for UTM, not lat/lon, and those grids are read differently. It’s been a few years since I used one, so my memory may not be correct.

Grim said...

So the reason it goes from right to left on the 'east/west' axis is that we are in America on the side of the Prime Meridian where that's the way the coordinates are measured. In Iraq, IIRC, they went from left to right because Iraq is on the other side of the line demarked by the Prime Meridian. (In the Southern Hemisphere, I think the north/south lines are reversed.)

The grids (UTM and MGRS are almost the same) on the map are 1km by 1km, or 1000m by 1000m. Thus the 1, 2, 3, 4, 5 etc. markings are 100m divisions of the km; and these are divided into tenths, which are 10m divisions of the km. So, if you see the coordinates hand written at the top they give you a location for one of the local cemeteries that is accurate to 10m.

In principle you can continue to subdivide, and with a bigger map or a computerized one you can do that. With these 1:24,000 scale maps, an eight digit grid is as good as is practical.

Grim said...

Sorry, the hand written coordinates in black are to the cemetery. The ones in red are to Neddie Knob, a local peak.

Mike Guenther said...

My late brother used to own a tree farm on Dodgen Ridge and for a short time, I rented a trailer about midway on Neddie Knob(mtn) Road on the edge of another tree field. Beautiful country up there.