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egosbar

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Post Finds the street but the number can be up to 500 meters off     
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My unit finds the streets ok but it has trouble finding the numbers. I live in a small town and it can be up to 500 meters off.

Does anyone know if a external aeriel will help it shows all bars from the internal one.

Do I need to download anything i only just purchased it but so far I'm far from impressed.

The mp3 hard drive is too small; it needs to be a least 20 gigabyte.





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Post Re: finds the street but the number can be up to 500 meters     
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I think you'll find that the problem lies with the maps. No one from the mapping software company goes to verify the exact location of every address on every street. As a result, some estimations are made about the numbers of the homes & buildings on the street. Obviously, addresses in city centers will be more densely distributed than those on a country road. Since a "lot" size in the city is much, much smaller than a lot in a rural area, this probably contributes significantly to the discrepancy that you are seeing.

Unfortunately, a better aerial will do only enable a quicker "fix" when the GPS is turned on, and hold the signal better in areas of heavy tree cover, etc. The GPS will continue point to the same latitude & longitudelocation as before, but the map software thinks that location should be house "number 203" on it when in actuality, it has "number 26."

I have been very happy with the accuracy of NavTeq maps (used on Garmin and other brands of GPS units). Updates occur a couple times a year to help reflect the latest construction. Many manufacturers support just one map software brand - but maybe yours will support an additional brand. Otherwise, return the unit and do a little more investigation into the devices and the map products available for them before purchasing another.

Good luck!





johmazz2006

GPS: Garmin Nuvi 765, Garmin 3950LMT, Garmin 2455LMT, Navman40, Garmin StreetPilot 3







Post Re: finds the street but the number can be up to 500 meters     
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egosbar wrote:
My unit finds the streets ok but it has trouble finding the numbers. I live in a small town and it can be up to 500 meters off.

Does anyone know if a external aeriel will help it shows all bars from the internal one.

Do I need to download anything i only just purchased it but so far im far from impressed.

The mp3 hard drive is too small; it needs to be a least 20 gigabyte.

You don't mention what the brand of the unit is. They all use different mapping company's.
I have used/ have three different GPS's, 2 x Garmin and 1 x Navman, and all 3 are accurate to within 3 to 12 metres of any street adddress I have done a search on and driven to.
Sounds like it could be a software problem and not doing the maths accurately.
Have you talked to the manufacturer yet ?

Also, MP3 hard drive too small ?? Not sure what you have there.
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Red

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Post Geocoding     
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Your problem is not unusual, errors up to 1/2 mile are common in certain areas. An external antenna probaly won't help, the errors are probably from the map datum that is used in your area, or the geocoding routines, which are the way that addresses get mapped to real lat/lon locations.

NavTeq is a bit sloppy about this, as are many vendors. And slow to correct it. On the other hand the latest "webupdate" set of patches for my Nuvi included a new set of geocoding information--which might fix the 200 yard to 1/4 mile errors I've been seeing.

About all you can do, is make sure that IF you gps has a choice of formats or datums, they are set correctly. If you have a town or couty survey office, ask them if there are any oddities locally, some towns do not use "normal" map datums. And once you've looked into that, contact the GPS maker to report the error. They *might* issue a geocoding correction as an update for your unit.





jason.learmonth

GPS: Skoda Columbus (RNS510)







Post Accuracy in a Rural Area     
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An external antenna will only really help in a CBD type I have found from experience. The GPS units are just so much better these day. And in that scenario it helps to locate you accurately on the right street rather than help with destination accuracy.

As you said that you are in a rural area, I too are in a similar situation and strike the same problem half the time with rural addresses. It just comes down to the mapping data that was retrieved or how an assessment was made where certain properties start. There isn't too much you can do other than provide feedback that the mapping isn't terribly accurate in those areas.
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gwcjr

GPS: Garmin Nuvi 2555







Post Address Problems     
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There are two issues:
One is that the GPS computes where the address should be based on standard conventions that are not followed in many areas or may be using less than perfect data obtained from governmental services and may have approximated some information.
The other problem is that the public/commercial GPS units are by design limited with a variance of accuracy to protect from its use as a military type device componet. This is either by the device itself or in the sattelite data supplied to it by the governement.
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