In-car and Hiking GPS or Sat Nav
Q. Is there a car SatNav that can double as a hiking hand-held GPS?
Phil Bryan, Sale
A. If you buy a Personal Digital Assistant running Windows Mobile you can install both a car routing application and a hiking application (eg Memory-map) and run them together. If you have a Tomtom there is an application called TTMaps that gives some hiking functionality.
John Thorn, Cardiff
A. I don't know of one though you can download 'apps' to some of the smart phones (like the iphone) which enable the phone to be used as an in-car satellite navigation (one 'app') as well as a hill and mountain walking satellite navigation system (another 'app').
The main problem with using a phone in this way is battery life. On the iphone the software doesn't work in the background so the software eats battery power like mad, resulting in a flat battery in a couple of hours at best.
This could be particularly hazardous if you then want to use your phone for that all important phone call to the emergency services!
I don't know what the battery life is like on other smart phones like the Nokia but I expect it is similar. This will obviously improve in time - but at present (2009) it isn't good enough for a 4 hour mountain hike.
Most hand-held GPS devices like the Garmin Etrex take standard AA size batteries that last all day and beyond and are replaceable with a couple of spares should they go flat. Incidentally, I use rechargeable 2500 mAh Energiser batteries and they last for about 24hrs continuous use.
Hope this helps