John:

Thanks. So just so I'm clear (I'm still in the dumb phone stage -- I even own and often use a dial phone when the power goes out): the iPhone will accurately record your GPS position and, if there's a wifi (or cellular) connection, can send an accurate gps-enabled location (as opposed to one derived from cell tower location)?

I'm getting interested in this stuff because several of us GIS/SAR geeks are putting together a guide on how to obtain location information from a cell phone emergency call. A lot of rural areas don't have e911 and, even when they do, it's not clear the accuracy of origin of location information given to responders.

A guy in the UK has developed a web site where the lost/injured person is sent its URL in a text message. When it's clicked on, the location information is captured on the web site. Of course, this only works with newer smart phones (Phase II).

Edging back on topic, I just looked for a Garmin topo of the John Muir Trail and found this:

http://www.gpsfiledepot.com/maps/view/143/

I loaded one of their topo maps last night onto the SD card of my Garmin 60CSX and it's pretty easy to do. Pretty good maps.

And here's another geeky thought: a friend has an Android app that records cell signal strength as he travels. He then generates a coverage map of areas he travels in. This would seem especially useful for marginal areas such as Whitney and along the crest. Inyo and NPS often get calls for help which last all of 20 seconds before the battery dies. Narrowing down where a call can potentially have come from would be a useful data set to have. A good and useful crowd sourcing exercise.

g.

None of the views expressed here in any way represent those of the unidentified agency that I work for or, often, reality. It's just me, fired up by coffee and powerful prose.