Anyone used MotionX GPS for the iPhone?

[PeterM]

Hi-
I'm an infrequent hiker in the whites, there sporadically thru the seasons & just returned from doing Welch-Dickey on Friday and the Boulder Loop yesterday. We were blessed with great weather especially yesterday.

I'm a month into iPhone ownership (G3s) and a couple weeks using MotionX GPS - it worked flawlessly here in Plymouth, MA but I had trouble acquiring signal at the trailheads on in clearview elevation. Wonder if others are using this as well. MotionX GPS is convenient & looks to be very accurate; here I can send a trackroute to 5 email addresses and Facebook before I even get in the car. The downside it sucks the batteries down real quickly I'm guessing 3-4 hrs tops and then you're left with no phone - camera - or "sob" YouTube :- )

So surprise, surprise, I'll continue to bring my Garmin 60GSx for the serious stuff, just wanna know anyones experience

btw great outdoors apps are Geocaching, Star Walk, Peaks (though hard to read) and iBird North(east) ($10 instead of the $30 for the full version)

Peter McLaughlin
Plymouth, MA

 

[DougPaul]

Don't know the specifics for the iPhone and MotionX, but...

Some cellphones use assisted GPS (AGPS). The approximate location of the phone/GPS is known (if only by the location of the nearest cell tower) and this information is used to speed up satellite acquisition and lock. A stand-alone GPS also has to wait 30 seconds for the orbital ephemeris to be downloaded but this information can also be downloaded via the cell data link to save time.

In effect, AGPS is a lot like a hot start* for a stand-alone GPS.

If your cellphone couldn't reach a cell tower at the trailhead, it could act like a stand-alone GPS at best. Some cellphones also use the cell data link to dynamically download local maps which, of course, requires at least intermittent contact to a tower.

Cellphones tend to use more power searching for cell towers when they are out-of-range, so standby battery life in the woods might be shortened over what it would be in town.

* in a hot start, the GPS has been used within the last hour or two so the downloaded information is still valid and not moved much so the last location is not far from the current location.

Doug

 

[PeterM]

Thanks Doug - I thought of that. We left from Conway yesterday down the Kanc - I didn't want to "waste" my battery. It may well be that & from the 60GSx I'm familiar as you travel a distance the acquisition time increases.

All-in-all for me I'd rather be outside enjoying nature than inside like today pondering technology. My best days include a woods hike with the pup as opposed to all afternoon with the quad-core

Peter
Plymouth, MA
& Epsom, NH