marion mt. trail to SJ summit - how long is it really????

[FIGHT ON]

Also, for what it's worth, there are high end gps devices with sub-meter accuracy real-time, and can be improved to centimeter accuracy with differential post-processing. But these require large backpack antennas in mountainous areas and under tree canopy. And honestly, I can't imagine why anyone would care about such precision for backcountry trails like this.

I've heard about these things. Pin point accuracy. I mean right on the dough. I think it would be worth the time to measure all the main trails at least. Especially the well traveled ones. If someone want's to pretend how far they go off those trails then who cares!

[Perry]

Of course, having to go slowly is one reason why people don't hike with wheels. The other big reason is that they are cumbersome and take all the fun out of hiking.

The experience of the outdoors is really the most important thing for most of us on this message board.

For a semi-tangent topic like this, that a few of us care about, it helps to have an understanding of vector calculus, statistics, and writing computer code such as MatLab. These things can become very complicated:
http://books.google.com/books?hl=en&id=YBYlCpBNo_cC

A simple way of understanding how a GPS device can be accurate is if you stay in one spot for an hour to eat lunch, and the GPS records data every 6 seconds. Then you have 600 data points, each with let's say 99% being within 18 feet of your location where you ate sandwiches (error has to be expressed with a corresponding probability). With Guassian distribution, many of those points would be closer (They are not evenly spread throughout a 36-foot diameter circle). With that much information, you have a very high probability of determining your exact location within a few inches or less. While hiking, the pace and sampling rate will influence such accuracy.

[Perry]

And my scenerio could be incorrect if the main issue is satellite location, as "some guy" mentioned. In that case a GPS unit would be even better at measuring hiking distance.
http://en.wikipedia.org/wiki/Global_Pos ... or_sources

[FIGHT ON]

A simple way of understanding how a GPS device can be accurate is if you stay in one spot for an hour to eat lunch, and the GPS records data every 6 seconds. Then you have 600 data points, each with let's say 99% being within 18 feet of your location where you ate sandwiches (error has to be expressed with a corresponding probability). With Guassian distribution, many of those points would be closer (They are not evenly spread throughout a 36-foot diameter circle). With that much information, you have a very high probability of determining your exact location within a few inches or less. While hiking, the pace and sampling rate will influence such accuracy.

I tell you what. I ain't no fizzasist, but I can show anyone in the world (((EXACTLY)))where the bottom of a wheel is at any spot on any trail, I'll just point at it, with my finger! You can't reinvent the wheel! some cave man figured it out already!