x-posted to TT - since it was a related TomTom question -

"John" <(E-Mail Removed)> wrote in message
news:aoejn.113775$(E-Mail Removed)2...
>I have a Garmin Nuvi 200W as my first satnav. I have been very pleased with
>it.
>
> Last week I acquired a TomTom One and decided to give it a try for the
> sake of making a comparison. I was surprised that the TomTom wanted me to
> stay on the defined route - even when I arrived at my destination after
> straying - it was telling me to turn around. Is this normal with TomTom -
> or is it just a feature of that model.
>
> I prefer the way the Garmin recalculates within seconds if you make an
> alternative turn.
>
> I guess my real question is "Do the different makers employ a widely
> different logic?"
>
I know when we went to a dinner,
a friend who has a TomTom - not sure which model -
took a slightly different route than I did with my Garmin.

Some differences can be due to device settings.... short, fast, avoid, etc -
Then there is just the weird things that happen every so often.

I tend to think the GPS logic is driven by straight line & stair step street
access,
and balanced with the speed limit of the streets involved.

In our case - haven't really timed it out for real, or via Google maps -
the Garmin GPS has us coming down I-335 and goes PAST our normal exit,
to get off at the next exit and work our way back...
Guessing the 50mph roads PAST our house are faster than the 35/40mph exit
roads.

ie - get from A to B in shortest/fastest path

ps56k wrote:
> x-posted to TT - since it was a related TomTom question -
>
> "John" <(E-Mail Removed)> wrote in message
> news:aoejn.113775$(E-Mail Removed)2...
>> I have a Garmin Nuvi 200W as my first satnav. I have been very
>> pleased with it.
>>
>> Last week I acquired a TomTom One and decided to give it a try for
>> the sake of making a comparison. I was surprised that the TomTom
>> wanted me to stay on the defined route - even when I arrived at my
>> destination after straying - it was telling me to turn around. Is
>> this normal with TomTom - or is it just a feature of that model.
>>
>> I prefer the way the Garmin recalculates within seconds if you make
>> an alternative turn.
>>
>> I guess my real question is "Do the different makers employ a widely
>> different logic?"
>>
> I know when we went to a dinner,
> a friend who has a TomTom - not sure which model -
> took a slightly different route than I did with my Garmin.
>
> Some differences can be due to device settings.... short, fast,
> avoid, etc - Then there is just the weird things that happen every so
> often.
> I tend to think the GPS logic is driven by straight line & stair step
> street access,
> and balanced with the speed limit of the streets involved.
>
> In our case - haven't really timed it out for real, or via Google
> maps - the Garmin GPS has us coming down I-335 and goes PAST our
> normal exit, to get off at the next exit and work our way back...
> Guessing the 50mph roads PAST our house are faster than the 35/40mph
> exit roads.
>
> ie - get from A to B in shortest/fastest path

Very often, of course, the same unit will calculate a different route when
returning from a location, than the route it took getting you *to* the
location!

Kev

On Tue, 2 Mar 2010 22:27:08 -0000, Ret. wrote:
> Very often, of course, the same unit will calculate a different route when
> returning from a location, than the route it took getting you *to* the
> location!

Sometimes that can be explained by turn weighting. An on-side turn
getting a different preference than off-side turns... Or it thinking
that going three-quarters of the way around a big roundabout is enough
distance difference to need a different route.

--
100. Finally, to keep my subjects permanently locked in a mindless
trance, I will provide each of them with free unlimited Internet
access.
--Peter Anspach's list of things to do as an Evil Overlord

Peter H. Coffin schreef:
> On Tue, 2 Mar 2010 22:27:08 -0000, Ret. wrote:
>> Very often, of course, the same unit will calculate a different route when
>> returning from a location, than the route it took getting you *to* the
>> location!
>
> Sometimes that can be explained by turn weighting. An on-side turn
> getting a different preference than off-side turns... Or it thinking
> that going three-quarters of the way around a big roundabout is enough
> distance difference to need a different route.
>
1. a calculated time of 30 seconds more makes that route not the fastest....
2. traffic lights are not an item in the calculation

Thibaud Taudin Chabot wrote
> Peter H. Coffin wrote
>> Ret. wrote

>>> Very often, of course, the same unit will calculate a different route when returning from a location, than the route
>>> it took getting you *to* the location!

>> Sometimes that can be explained by turn weighting. An on-side turn getting a different preference than off-side
>> turns... Or it thinking that going three-quarters of the way around a big roundabout is enough distance difference to
>> need a different route.

> 1. a calculated time of 30 seconds more makes that route not the fastest.... 2. traffic lights are not an item in the
> calculation

They are in the latest TomTom engine, users can allow the
TT to upload actual times taken over a particular route.

Its less clear how many allow their TTs to upload
that data and how much data they do get that way.

On Thu, 4 Mar 2010 03:56:10 +1100, "Rod Speed"
<(E-Mail Removed)> wrote:

>They are in the latest TomTom engine, users can allow the
>TT to upload actual times taken over a particular route.
>
>Its less clear how many allow their TTs to upload
>that data and how much data they do get that way.

How does that 'upload' function work? Do you periodically connect the
GPS to a computer to download the data from the GPS?

Sunshine wrote
> Rod Speed <(E-Mail Removed)> wrote

>> They are in the latest TomTom engine, users can allow the
>> TT to upload actual times taken over a particular route.

>> Its less clear how many allow their TTs to upload
>> that data and how much data they do get that way.

> How does that 'upload' function work? Do you periodically connect
> the GPS to a computer to download the data from the GPS?

Yes. Its optional tho, you dont have to allow it to do that.

On Thu, 4 Mar 2010 06:02:19 +1100, "Rod Speed"
<(E-Mail Removed)> wrote:

>Sunshine wrote
>> How does that 'upload' function work? Do you periodically connect
>> the GPS to a computer to download the data from the GPS?
>
>Yes. Its optional tho, you dont have to allow it to do that.

Thanks.