View Full Version : New score

2006-03-25, 23:09
Stopped off at a estate sale today on my way home from the hardware store.
Got a whole series of Forest Service maps of the Bitterroot National Forest for 50 cents!
I think they cover the entire forest.
5 maps each about 2 feet square, scaled at aprox. 1 inch to 2 miles.
Small amount of wear on the edges, but in very good shape.

O.K. they might be slightly dated (1964), but in my world view that isn't that old. And for my uses they will work pretty good.

2006-03-25, 23:32
Dropkick I'm fairly certain the mountains are still in their same locations since 1964 but I wouldn't bet the same on the roads, especially the Forest Service roads. Also, check and see what the current declination is for that area, I'll bet it has changed a degree or two in forty-plus years. Also note the datum, if would have to be NAD 27. Most, but not all, current maps use WGS 84. This can cause a descrepancy of a couple-hundred yards, especially near the map edges. If you'll be using a GPS along with these maps, make sure you change the datum and you should be good to go.

2006-03-25, 23:36
What He said,

Take-a-knee beat me to it by 60 seconds and fleshed out the NAD/WGS stuff better than I could.

2006-03-27, 21:02
I'm still one of those guys who uses a compass and the map and doesn't own a G.P.S. I worry more about declination and being off in my navigating by a few miles. A few hundred yards is nothing.

I had to look up NAD 27 and WGS 84. While I was somewhat aware of the change, I don't think it had really entered my conscience mind.

First we had chains, measurements from set "known" points, moved to the North American Datum of 1927 (NAD27), and then North American Datum of 1983 (NAD83), after that we went to the World Geodetic System 1984 (WGS84) which is the same as NAD83, but then we wouldn't have to put up with all the nads jokes. i.e. "You think everything is centered around your nads" or "Grab your nads and come over here."