How exactly do GPS apps work?

[A.Nonymous]

I'm looking into some mileage tracking apps so I can track my mileage at work. There are several on the market that work via gps. Basically you press a button when you start your trip and another button when you end it. My question is about how these apps actually track you. Do they track your location as the crow flies (i.e. they look at your start and end and calculate the distance straight between) or do they calculate based on the actual roads you have to take to get from A to B? I'm wondering if I'd be better off with just an app where I record my miles directly and don't mess with GPS. Can anyone recommend some good mileage tracking apps?

 

[PhoenixFx]

I haven't used a tracking application mu self, so I cant be of much help in recommending one. But as for how they work, I assume they take periodic GPS readings and calculate your movement based on your position changes. IMO that is the most logical and the simplest approach to develop a tracking app.

 

[terry_gardener]

i have not used a mobile phone gps tracking app but i have the garmin edge 605 to track my cycle rides (distance, time, speed etc)

gps signal establishes where you are, and the software works out your speed, direction etc. if you combine this which a map like google maps or similar map it already knows where you are and can plot your route on the map as a overlay.

for example one of my routes/data
27-07-2010 by terry_gardener82 at Garmin Connect - Details

i would expect a tracking app to do something similar to the garmin.

if you do a google search it will give websites that go indepth how gps works.