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Dallas Freeways confused my GPS?


Mike O

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I had the occasion to visit Dallas on Tuesday evening for a business trip. Not having driven through the area in some time, I thought it wise to bring the Garmin Quest GPS along to help navigate from the Dallas Fort Worth Airport to Plano and other points as well. This area was just south of the airport and is representative of the areas I drove.

 

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Even with the GPS, however, the complex freeway system around the DFW Airport had me driving all sorts of side roads (and unfortunately, in the dark).

 

As near as I can tell, the GPS did very poorly near any of the complex, tightly integrated and dense overpasses. The GPS was constantly sending me off the freeway and then back on again (each time costing me 40 to 75 cents!). I suspect this was due in part to not having any kind of real ‘vertical positioning’.

 

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FWIW, I did check the GPS for satellite signal quality and had a lock on at least 6 birds (and accuracy to 30 feet). Still confused the GPS.

 

Is this common around these multi-tier overpasses? If so, how do folks handle the GPS becoming confused?

 

Regards,

 

Mike O

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I'm curious to know if you loaded the maps with the 'highest' detail setting.

 

I have the same unit. I know GPS is 'old' technology, but I am blown away by that thing. I've only had it since July/August.

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I'm curious to know if you loaded the maps with the 'highest' detail setting. ...
I loaded the maps for the Dallas area (including all additional areas I was planning to navigate). I'm not aware there is a setting for loading more or less 'detail' when loading maps to the GPS. Nor do I think the detail setting on the Quest would have any bearing (pun intended!) on the ability of the GPS to properly track and provide routing guidance. Am I missing something?

 

Mike O

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The detail is on the mapsource software. When you load up the software it should be on the left next to the toggle to send the data to the garmin.

 

I doubt this would make any difference in your case. But another thing you might want to look at is avoidances and preferences settings.

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While getting to the headquarters of The Void II (rally), in Lynchburg, VA, we travelled a recently imporoved interchange/bypass. Unfortunately, even with v.7 of the map software, we were apparently driving 'off road' for a good bit of the trip near Lynchburg. Since we could see that we were on a highway, we just kept going and watching for signs taking us the direction we needed to go and ignored "Mrs Peal's" instructions to take various side roads (We've set our GPS to speak British English. Mrs Peal >as in Emma Peal from the Avengers, I believe< seemed appropriate.)

 

Eventually Mrs Peal figured out where we were, relative to maps she had and we arrived safely.

 

Particularly around cities, interchanges and bypasses often are constructed without consulting or informing Garmin. It is kind of fun to see the little arrowhead heading off through tan 'fields' on the screen.

 

Pam

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The detail setting does not affect routing guidance, just the level of road detail displayed on the map at a given zoom setting.

 

Some of those intersections near DFW can be nasty and even rival anything California has to offer in terms of complexity. I also have had difficulty navigating them via GPS because there are so many ramps heading off in so many directions so close together. What I do in that case is to go by the written directions given by the GPS and ignore the map display, meaning if the directions say to use 'Hwy 183 West' then I look for the appropriate road signs and follow them vs. following a line on the GPS. This tactic usually works well for me in extremely dense areas.

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ShovelStrokeEd

Heck, my GPS V gets lost all the time. It has a lot of trouble with parallel roads and the like. First thing I do is see if the direction given by the GPS makes sense to me. Next is watch road signs, final is to just follow my heart.

 

I have had better luck with programming a waypoint a little ways down the road I want to be on. When in the DFW area, I frequently stay at the Hilton just up the road from 6 Flags. I get the coordinates from Streets and Trips and then program them into my Garmin as a waypoint. This way, if I'm coming across on I-20, as I get into the airport area, I just do a goto-fastest way to the waypoint. Be sure your preferences are set to use highways and toll roads and you should be good.

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Roads around major airports are always under construction and being moved around, so you should just assume the maps in your GPS are out of date near the airport.

 

Multilevel roadways block the GPS signals so you'll likely lose satellite lock on roads like the ones you showed.

 

Two (okay, three) data points:

 

This March I was leaving the Atlanta airport with a GPS 2610 and a Hertz Neverlost GPS in the rental car. Both directed me onto the same route, away from the road in the airport marked "To I-75", onto back roads for many miles before meeting up with I-75 again.

 

On the Iron Butt Rally last year, I was depending on my 2610 for navigation across New Jersey and New York. At several points getting onto the Jersey Turnpike, the turns came up too fast for the GPS to announce the next turn and I kept missing them, until I finally just looked up and followed the road signs. Then, crossing the George Washington Bridge, I was on the lower level, so of course, the GPS lost satellite reception. I had just enough time to page to the next screen to find the next turn and look up to find that the turn was immediately at the end of the bridge NOW!, where the GPS had no chance of locking on in time.

 

Moral of the story is, use common sense, don't depend entirely on the GPS, know where you're going, and sometimes you're better off not listening to the GPS and just following the road signs.

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You didn't state what GPS you have, nor the version of software it's running. I have a Garmin Quest, using Mapsource v6.7. I have had no issues around the Dallas area. However, I have not used it in the Plano area. North Dallas highways have been under continous construction for many years. Just like many major cities. Depending on where you traveled, the intersections have changed many times during the past year. I suspect that you software is based on older construction roads that no longer exist.

 

My Garmin in not perfect, but in a majority of the cases, it works great.

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Rocket_Cowboy

Without knowing which particular interchange was the problem, or the particular on GPS software/model, I will say that there's been enough change in the area with the new 190/161 toll extension, 121 work, and the "high-5" intersection being completely redone between I-635 and 75. None of my GPSs have it right ... from the one in my car, or either Garmins using either City Select or City Navigator. Other than that, I've had pretty good luck with my 2730 keeping signal through those overchanges, and not mis-routing me, though it did get a little confused earlier this month when I rode through Indianapolis.

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Garmin Quest with 4.0 version firmware and City Select/MapSource v6.9

 

Unless someone moved the 360/183/George Bush Freeway, I suspect it has more to do with the cluster of choices the GPS finds. But I'll update to the latest 6.11 Mapsource.

 

It's been a while since I've driven around Dallas and I'm amazed at the multi-tiered highways. My passenger noted that we'd be in deep sh!t if we broke down near the top of one of the overpasses.

 

Regards,

 

Mike O

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Updating MapSource won't make any difference. That's the software that your PC uses to display the map data. CitySelect is the map data that's loaded into your GPS and on the DVD that comes with the GPS.

 

Another question - with the Quest, you have to load detailed map data from CitySelect (using MapSource) into the GPS for the area you're riding in, otherwise you only have the built-in basemap that only shows major roads, crudely. Did you have the maps loaded for that area?

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Updating MapSource won't make any difference. That's the software that your PC uses to display the map data. CitySelect is the map data that's loaded into your GPS and on the DVD that comes with the GPS.

 

Another question - with the Quest, you have to load detailed map data from CitySelect (using MapSource) into the GPS for the area you're riding in, otherwise you only have the built-in basemap that only shows major roads, crudely. Did you have the maps loaded for that area?

I wouldn't think upgrading CitySelect (Mapsource) would make a difference either, but I'll update none-the-less (looking at the bug log there may be some relevant fixes). As for your other question, yes, I downloaded the appropriate detailed map data for the Dallas area.

 

It strikes me that there are only a few things that could cause this behaviour:

 

1. GPS's just can't handle the density of freeways like those I encountered in Dallas

2. The GPS is broken, although I did not have any problems with GPS navigation in other areas of Dallas)

 

I'm inclined to think it's the former (GPS can't handle the density), but wanted to know if others experienced similar GPS behviour (and maybe with other models as well). In the mean time, the best advice I've received in this thread is don't rely on the GPS...

 

Still curious.

 

Mike O

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The maps for the GPS - I run a SPIII using v.8 of City navigator - can be from 6 months to 2 years behind the construction curve. There is an extension of the street my office is on that was completed over 2.5 years ago and just now is showing up in City Navigator - but it is not in MS Streets & Trips yet.

Look at the directions before coming to a constrained section and get an idea of what roads you want to be on and going towards and just watch the directional signs. I was in North Adams,MA and the gps said turn left - but I was on a bridge and the road to turn onto was under the bridge, I got onto the road but not in the way the gps wanted me to.

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It strikes me that there are only a few things that could cause this behaviour:

 

1. GPS's just can't handle the density of freeways like those I encountered in Dallas

2. The GPS is broken, although I did not have any problems with GPS navigation in other areas of Dallas)

 

I'm inclined to think it's the former (GPS can't handle the density), but wanted to know if others experienced similar GPS behviour (and maybe with other models as well). In the mean time, the best advice I've received in this thread is don't rely on the GPS...

 

Still curious.

 

Mike O

 

Mike, here's another item to your list:

3. GPS mapping firmware (software) has a bug.

 

In dense areas it is possible that the GPS is getting confused because too much is happening too quickly - or to put it another way - the software is in the process of making a decision when more information comes which causes the GPS to make a bad decision (mistake?). Kinda like when I'm talking on the phone and my kids interrupt me! tongue.gif

 

From what I've observed on the road comparing a couple GPS units, it's REALLY NICE to have a fast GPS. As others pointed out, it's difficult to drive safely and not get lost if one is relying on the GPS for directions and the GPS can't keep up. Unfortunately there isn't a "spec" which one could use to show how quickly a GPS will operate.

 

My rule of thumb, be patient and drive safely as I figure the GPS will "eventually" get me to the destination.

 

Greg

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Mike, here's another item to your list:

3. GPS mapping firmware (software) has a bug.

 

That's what I meant by #1 "Broken".

My rule of thumb, be patient and drive safely as I figure the GPS will "eventually" get me to the destination.

 

Greg

 

Yup, that's what I did last Tuesday nite. After entering and exiting 3 or so freeways/turnpikes and $5 or so bucks later, I did get to my destination. It was, however, embarassing since I was bragging to my companion about how great the GPS was (he laughed the whole time and asked if I should just ask for directions!)

 

Mike O

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Yeeha! Stephen

Ditto what Cowboy said.

From the picture of the Tan painted overpases, it looks like you were in an area where the highway has actually been moved. Not much, but just enough for the GPS to think you were on one of the "old" service roads. Thus, it tried to route you "off" the service road back "on" to the Freeway the best way it knew how. Only, what's on the ground now, doesn't match what's in the MapSource.

Fun huh?

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