GPS Unit or Mapsource equal in route planning?

Am curious - for an 'optimal' routing (distance or time), is it better to do
a route on your PC where you bring the bear to massive power of your PC, or
if you do the same on your little GPS, does it make a difference? In other
words, does the PC routing look deeper into routes than your GPS unit can so
that it's better to do complicated routes on the PC side then download?

Just curious....

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Regards -

- Andrew

With Garmin's current line of routing receivers, it looks like you
really don't have any choice.

When you generate a route on your PC using MapSource and then send it to
the receiver, all that really gets sent is the set of waypoints you used
to generate the route.

When the receiver starts navigating, it's always going to recalculate
its route from your current position to the next waypoint, using its own
algorithms with whatever info is embedded in the map data and the
limited set of preferences you're able to enter into the receiver.

Or at least that's the way it works on my 76CSx.

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Bert Hyman        St. Paul, MN        bert@iphouse.com

Bert Hyman wrote:

Same here. I've found that if I want to go a specific way,
inserting "midway" waypoints are the only way to ensure that
the handheld routes the same as MapSource.

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Steve

I haven't noticed that routes created on my computer with MapSource
are any better than those created on my 76CS. Often different, but
not necessarily better (or worse). I assume the differences are due
more to different algorithms than differences in computing power.

Depending on the unit, a route created in MapSource may or may not
transfer intact and be identically reproduced on the GPSr. On my
76CS, they are not. If I use enough intermediate point in strategic
locations along the route, I can get it to follow a particular path.
But all that is transferred from the computer to the unit are the
points on the route. The receiver uses the points to calculate its
own route, and if I haven't been sufficiently clever in anticipating
where to put intermediate points, it may be different from the one I
created on the computer. It is amazing sometimes how resourceful the
76CS can be in finding some path other than the one intended which
still goes through all my carefully picked intermediate points.
Fiddling with the routing preferences helps sometimes, but not
always. This has been a source of frustration to many people, as you
can find if you do some Google searching for previous posts on this
topic.

I am pretty sure that some units do receive a route created in
MapSource and reproduce it exactly as it was created. I believe these
are generally the dedicated automotive units (those that use routes).
I think I recall someone posting that the Quest units do this.

If I was familiar enough with the place to which I'm traveling to be so
clever, I wouldn't need the receiver to help me get there.

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Bert Hyman        St. Paul, MN        bert@iphouse.com