[Cdt-l] Using iPhone for GPS

BCSS bcss at bresnan.net
Sun Mar 1 09:01:53 CST 2015

When GPS was first developed, it was much less capable than it is now. There were no background maps and navigation was achieved by a compass style needle that pointed towards a waypoint and listed the distance you needed to go in a straight line to get to it. As the devices became more and more popular, background maps and track lines became part of the package, but the old needle and distance remained as an option.

Guthooks is a purely "follow the yellow brick road" sort of application which uses an extremely detailed track line, and waypoints have become informational data instead of navigable data.  

When we surveyed the trail we collected points on a one second interval in most cases, which resulted in the roughly two million of points which comprise the USFS database.  Most GPS receivers can only handle track files of 10,000 points so over 200 separate tracks would have to be loaded in a conventional GPS to show them all.  I overcame this issue in the track files available on our website by thinning the points.  This results in some lack of detail - switchbacks get short cut, etc.  This has not mattered much because the waypoints are still there as well and navigable in a conventional GPS.  

The tracks in the Guthooks apps are more robust and show greater detail but the waypoints are not navigable in a classic "pointer and distance" sense. If you see on the screen that you are off of the trail line you simply zoom in close and walk towards it until you are back on track. It is elegant in its simplicity and makes it very easy to understand and use.  The addition of photos of many waypoints, elevation profiles that actually make sense, and Databook information really make it a hiker friendly tool, and IMO, makes it a great alternative to carrying a conventional GPS.  

best wishes,
Jerry Brown
Bear Creek Survey Service, LLC
3065 East 2nd Avenue
Durango, CO 81301
(970) 403-3527   cell: (970) 317-1398
bcss at bresnan.net

> On Mar 1, 2015, at 7:00 AM, Bob Sartini <bobsartini at gmail.com> wrote:
> I kept my phone (android) on in airplane mode and turned the GPS on for just a moment to check my exact location which showed a blue dot on the trail. In airplane mode, off at night, it lasted for six days. It took a while to get how to orient it and such like any map and I did understand it well enough.
>> On Sat, Feb 28, 2015 at 4:16 PM, b j <xthrow at yahoo.com> wrote:
>> What are your thoughts on using my iPhone for GPS info for those few moments where you really really would like to know where you are?  (otherwise, I'll be relying on maps and compass navigation)  
>> Does Guthook tell you whether you're on the trail and where you are on the trail, and if you're not, what direction you need to go for what distance, similar to halfmile's app on the PCT?
>> Or is there another GPS app that you recommend for this application?
>> -Porsche
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