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How are Garmin's products for trip planning?
Ken in Regina
Quote:
Originally Posted by GoneNomad
[B]Which first leg does the (green) route to Miami take?

My guess is, it commits the same error as the (blue) route to Nashville.
Yes. Green and blue are identical. I forgot to mention that. I've looked at these routes so much now in various combinations that some of it has become really obvious .... to me. I forgot that you only get the finished product and it's just a picture that can't be messed with for clarification.

As I mentioned before, I understand and don't disagree with your observations about what's right and wrong for we humans to use the resulting routes. I've just been trying to balance that judgement with some of the factors that can cause it.

...ken...
Ken in Regina
Quote:
Originally Posted by GoneNomad
I think Garmin's (or other PND) route calculations, being optimized to not take too long on a relatively slow CPU in a PND, become less "fine" (more coarse) on longer routes. Google's server-based approach doesn't suffer that limitation (in practical terms).
I never considered that but it's an excellent point. Of course the PC algorithm should be as close to the PND version as possible, even though it will likely have more horsepower available.

...ken...
Ken in Regina
Quote:
Originally Posted by GoneNomad
Maybe Windows Maps will get there (and I'd sure like to have better Nav than S&T on a Windows device), but right now, if Windows Maps mirrors what Bing.com/maps does, it isn't there yet.
Did you want me to check that?

...ken...
GoneNomad
Quote:
Originally Posted by Ken in Regina
Green and blue are identical. As I mentioned before, I understand and don't disagree with your observations about what's right and wrong for we humans to use the resulting routes. I've just been trying to balance that judgement with some of the factors that can cause it.
...ken...
Well (for example) if they have a routing parameter that strongly favors interstate highways unless it's more than say, x% farther, and/or takes more than x% longer, that would explain why it uses one route for a shorter trip, and an entirely different route for a farther-away destination after passing the first endpoint.

The route favored by Garmin is a reasonable route IF (for some reason) you need to travel only on interstate highways. It might be considered the optimum RV or truck route.

But, in the real world, if the northern part of the green & blue Garmin routes are the "right" or "best" one, then the (purple) route to Paducah one should go that way too.

That's what both Google & S&T 2013 do, even though each one chooses a different default route, the route DOES go the same way no matter how much further you go, e.g.:

S&T2013 Imperial-to-I24 near Paducah
S&T2013 Imperial-to-Nashville
ref.: http://imgur.com/a/eLZVt

It's apparently a close call for S&T, because here's what happens if I adjust the destination near Paducah slightly, moving it farther north, or east of I-24, this is what happens.

But as long as the destination is far enough to the south that the "short-cut" via KY286 makes sense, that's what S&T AND googleMaps use. This agrees with my extensive anecdotal experience of what the "right" route is for this trip. I could cite other examples, but I use this one a lot because it's probably the best one. it sure does give "Here" fits!


And in my experience, that's a good thing, especially considering that on small-screen mobile devices, you probably can't review a route nearly as well as on a large desktop monitor. Planning a route, on a desktop trip planner, then changing it later to a slightly different - seemingly inconsequentially different - destination, only to have the route (that you had seen in full before on the desktop) automatically change to something entirely different... is not acceptable.

I can accept that different routing algos favor different parameters. But I can't accept the readily apparent real-world routing inconsistencies our tests have uncovered.
GoneNomad
Quote:
Originally Posted by Ken in Regina
Quote:
Originally Posted by GoneNomad
Maybe Windows Maps will get there (and I'd sure like to have better Nav than S&T on a Windows device), but right now, if Windows Maps mirrors what Bing.com/maps does, it isn't there yet.
Did you want me to check that?

...ken...
Sure, if you have time, that would be great.

Also, I'm wondering if this problem is replicable: Bing.com/maps repeatedly changed my intended destination (a Walmart in Nashville) to the nearest WalMart to the starting point.

Seriously, it would not let me chose that Nashville WalMart unless you enter only the address!
GoneNomad
Quote:
Originally Posted by Ken in Regina
...Of course the PC algorithm should be as close to the PND version as possible, even though it will likely have more horsepower available.
...ken...
i would sure hope that "totally default" routes (i.e.: the first or default route with no changes to routing prefs.) in something like Basecamp/Mapsource would match the routes between the same start&end on any recent Garmin PND. Otherwise, users couldn't be sure which route they'd get, depending on which Garmin app/PND they used.

I would understand if a significantly older Garmin PND (with the latest map) might not come up with the same route as a more recent PND (with the same map), though, because I assume that some of the algos are baked into the firmware, not affected by map updates.
Ken in Regina
Quote:
Originally Posted by GoneNomad
Quote:
Originally Posted by Ken in Regina
Quote:
Originally Posted by GoneNomad
Maybe Windows Maps will get there (and I'd sure like to have better Nav than S&T on a Windows device), but right now, if Windows Maps mirrors what Bing.com/maps does, it isn't there yet.
Did you want me to check that?

...ken...
Sure, if you have time, that would be great.
I've started a new thread in the Microsoft section for this.

http://www.laptopgpsworld.com/5671-windows-maps-app-testing#post50869

...ken...
werdnanostaw
I suspect you've both probably had enough of testing navigation programs, apps and PNDs but ...

How do they handle "off route" and "recalculating route"? Do they re-route onto completely different tracks?

This would be a major problem if you'd seen that the original route went through a required location that you hadn't made a waypoint that the new route now bypassed or if you were a high vehicle driver and the route now directed you under a low bridge.

I don't know how you'd test this without actually driving a test route and deliberately going off track.

At least you can see if they have an option to not recalculate if off route. I always enable this so that my carefully crafted route isn't messed with.

In our case short range getting back on track is handled by the PND while the PC software keeps the original route. It's the copilot's job to make sure we're heading in the right direction to meet up with the required route. Sometimes the copilot's CPU isn't powerful enough to recalculate in time so I have to wing it using the satnav system built into my brain.
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