[pct-l] pct-l] Follow-up to the earlier GPS discussion

[Bill Burge]

That's horrendous!  ;-)

I remember when the "pre-programmed" random error amount that was included in non-military GPS units was larger than that!

Selective Availability
http://geography.about.com/library/weekly/aa050400a.htm

 May 2, 2000 in the timeline
http://en.wikipedia.org/wiki/Global_Positioning_System

Bill Burge
bill at burge.com



On May 19, 2010, at 11:39 AM, <gwschenk at socal.rr.com> <gwschenk at socal.rr.com> wrote:

> ---- abiegen at cox.net wrote: 
> 
>> My brief time on the PCT this year tells me that everyone is either using a GPS or HalfMile's excellent maps which are based upon GPS tracks. Looking at HalfMile's maps you can see that on the underlying maps the PCT is often incorrectly placed, sometimes by a considerable degree. I suppose that those using only maps are okay with the trail being some 100 feet or so off from where they are actually walking. So part of the skill of using maps and compass only is the ability to live with an imperfect depiction of a changeable trail.  This is easy to do when the trail is very visible. Less so when it is covered by snow. Lots of snow this year so lots of people looking for more accuracy on the trail.
> 
> An inexpensive handheld GPS receiver can also have error of as much as 100 feet. Maps can be off, such as at Spanish Needle, but GPS has its own inaccuracies.
> 
> Gary
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