Sat Navs

[rov1200]

How does the Sat Nav calculate the shortest route? In some instances a longer route is chosen which is not my preferred one? Also what branch of mathematics is used to calculate routes?

[sarah_louise]

Something to do with NP I believe.
Here is a nice useless fact. Not sure if it is correct though.
In mathematical terms, the number of routes grows as n!, or factorial n, where n is the number of cities. With four cities, for example, the number of routes will be 1 � 2 � 3 � 4, a total of 24. For just 25 cities, however, finding the best route is equivalent to finding one particular raindrop in all the world's oceans.

[Panic Button]

In my experience you are better off choosing quickest route rather than shortest.

[mrs.chappie]

I agree with PB.

[rov1200]

I quite agree Zacmaster. Driving on motorways is just too boring even though it is far quicker. This is also when sat navs come into greater use as you don't need one just to travel up the M6 or whatever.

[rov1200]

I was hoping that someone would suggest the following:

http://en.wikipedia.org/wiki/Network_topology

[fo3nix]

http://en.wikipedia.org/wiki/Traveling_salesma n_problem