Google Maps Now Does Interactive Re-Routing

An anonymous reader writes "Remember how cool it was the first time you used MapQuest or Google Maps or Google Earth? You'll feel like it's the first time again, when you use interactive dragging of routes on Google Maps. Some of the folks from the development team have even whipped up a handy video to explain the concept."

excellent feature

[sh0rtie]

i noticed this today and its a good idea though the most complaints i hear from my customers (uk) when i point out how Google maps works and how to use it is the accuracy of driving directions, and so they tell me after using that they still prefer to use Mapquest/AA even though their visualisation of mapping is inferior to Google's, fancy draggable routes mean nothing if the directions are wrong or inadequate for route navigation and so i cant really argue with them because its true (in my/customers experience)
while calculating directions is a very complex task (1 way systems, roundabouts, roads closed etc) i think this is a challenge that Google could excel at

I'd like to see

[lawpoop]

I'd like to see editing of the small turn maps that they have on the print screen. I don't need a little map to show me the turn out of my street at the beginning on the trip. I always get rid of it.

However, I would like maybe to see the 3 or 4 major turns in the trip, or a close-up view of some smaller, complicated streets that don't really resolve in the map of the entire trip.

Traveling salesman..

[harrkev]

I also noticed that they did not solve the "traveling salesman" problem. If you add multiple stops, it will happily have you doubling back on your route. I have not yet seen a mapping program what will organize your stops in an optimal patters.

Yes, I know that a solution to the traveling salesman problem would take an extreme amount of procesisng power (maybe years). But there are shortcuts that are "good enough" and can be accomplished a fraction of a scond on a modern processor even with 20 stops. Doing five or so stops should be a piece of cake. You just need to develop reasonable hueristics.

Re:Traveling salesman..

[Anonymous Coward]

I also noticed that they did not solve the "traveling salesman" problem. If you add multiple stops, it will happily have you doubling back on your route.

What are you talking about? Just because you 'double back' on your route does not mean it is inconsistent with the TSP. It may simply be the most optimal, for its definition of optimal route. Most software will optimise over travel time, rather than simply distance (you don't want to travel dirt tracks forever do you?) and usually it makes sense to return to the main road, even if this means a brief journey away from your destination, or even repeating part of the route you have performed.
Optimising over travel time is NOT the usual TSP optimisation problem, and if if you do optimise over distance, what's wrong with backtracking? If one city had to be visited, and that city had only one road in and out, how could it be avoided?
Contrary to what you and some other posters have pointed out, solving the TSP problem "good enough" is actually rather trivial. The simplest approach is a generic algorithm. Look it up.

Re:Traveling salesman..

[LnxAddct]

It's a little more complicated than the traditional salesman problem because these graphs are weighted and directed. Even then there are still good algorithms to calculate such routes. Most algorithms are "fast", but not 100ms or 200ms fast. For the speed and scale that Google does this at, it's pretty damn impressive. (Scale being both the size of the graph, and quantity of queries received)
Regards,
Steve