wrong home location

[bassfisher6522]

My home location is wrong on my new tom tom. Using Google earth and checking lat and long of my tom tom, both of them are really close in the numbers...just off a hair. Using Google earth to pin my location and then check the lat and long I get the correct lat and long readings. Before, I would guess a year ago Google earth had my location off by about 2 miles. now it's off less than a quarter mile. Where as my tom tom has my location around the old Google earth location (2 miles). Is there a way to manually force the correct latitude and longitude numbers into the tom tom? When coming back from a trip into town and to here Mandy tell us we have reached are destination and we still have about 2 miles to go is a bit annoying. I've contacted tom tom via email a week ago and yet have had a reply.

 

[dhn]

On your unit you can change your Home to your current location. It'll then do so based upon the current lat/long data from the gps.

That said, many feel it is NOT a good idea to show the specific location in case your unit is lost or stolen. Select a street intersection close by, for example. That way, your planning routes will be pretty precise but a thief looking for your house will haveproblems. And that is the point.

 

[bassfisher6522]

I thought that all gps units were so accurate, that they could pin point you location with in 3 feet....well that's the claim. In my device, when the initial set up asks for my home address and I input the data and it search's for the satellite's and then acquires my location and it comes up 2 miles off some thing is wrong. Werther it be faulty data input or the generalized answer that I've found about blocks being equal and then splitting it in half causing the error, the problem should be addressed by some one. None the less thank you for your reply and answers on this forum. You have been very helpful to my inquiries.

 

[dhn]

No consumer gps will be that accurate, if the truth be known. Within 10 meters 95% of the time is the best that can be hoped for.

Sometimes it is a mapping error causing the displacement.

 

[canderson]

I thought that all gps units were so accurate, that they could pin point you location with in 3 feet....well that's the claim.

A good handheld GPS with WAAS (FAA) satellite correction data is often repeatable to about 10' with a good satellite constellation, protestations to the contrary notwithstanding. Your TomTom doesn't use WAAS, so I wouldn't suggest a repeatable location to down to more than about 20'. But as you can see from those numbers, the problem in this case isn't the GPS, it's the maps.

The various mapping services attempt to geolocate major features (especially roads) so that the coordinate system in current use (typically WGS84) allows you to move to a latitude/longitude and be at the feature in question -- e.g., an intersection of 1st and Main streets. However, NONE of the mapping services are perfect in this regard, and sometimes miss by a good bit. Eventually, a lot of these errors get corrected by overlaying the projected location and a satellite photo view of the same area. There are still places where firing up Google and turning on the street traces shows a whole lot of difference between where the streets actually are and the traces to represent them. The traces are built from inaccurate coordinate data during geolocation. (whew)

Addresses ON a street are another story altogether. All kinds of resources are used, right down to human visits to areas to log address ranges as a recheck against the original data. LOTS of room for human error in that process, and where the exact range of addresses on a block isn't known, it's often interpolated (read: Scientific Wild Ass Guess).

You'll find this to be the case no matter which GPS you use since they all depend on some mapping service somewhere for the raw data. Some are better in one area, and some are better in another -- because they're not using the same service, or if they are, not necessarily running the most recently available map data.

And like DHN says, if you really want your home location nailed, just set home to your current location with your TomTom when you're in your driveway. And like DHN also says, that's not necessarily a good thing if you're on a road trip and your GPS gets swiped.

 

[bassfisher6522]

No consumer gps will be that accurate, if the truth be known. Within 10 meters 95% of the time is the best that can be hoped for.

Sometimes it is a mapping error causing the displacement.

I guess 30 feet is not too bad.....for pin point accuracy....lol. Still it just bums me out that my home location is off that much.....aside from the fact you pointed out about the theft thing and finding my place. Nice tip btw. When the technology catches up to the nav gps markets for add ons features like; hide home address, all blue tooth capable, battery charging indicator and so on....to make them feature rich like most smart phones. I'm just wondering why they don't do set up like that. It would be nice and at a price that's affordable.

 

[Arno]

In February 2008 Google switched to updated maps and in the process moved my street address six houses over and across the street.
The satellite coordinate had not changed except that the winter shot of my pool now was a brilliant summer shot.

I eMailed Navteq, telling them that I was just about ready to buy a GPS and asked them why they had changed from an exact, correct location to an updated wrong addressed map.
The reply was that they would look into that but that every complaint must be verified physically by their team and that it would take at least two years as there were only two persons to check the Province of Ontario (only a bit bigger than Texas).
Google then switched to Tele Atlas maps which carried the identical error.

By and large, my 930 gets me pretty close to where I need to go but for the exact location I will still have to look at actual house numbers.
That can sometimes be a bit annoying if looked up with Google Street View as that 100 yard shift applies there too and the moved view point jumps usually past the places I am trying to locate (= print a picture for SWMBO so she doesn't have to find out what North. South, East, West means, one day).

Places which I revisit often I put in a custom POI.
After entering the street address and saving it I will open it with TYRE, click Edit > Display in Google Maps and drag the pointer to the exact location.
(dhn referred to home location. Mine is a ramp off the express way bout three light from my home. For the actual home I just use the street name but drag the location to the correct spot, per above.)

With paid GPS services accuracy can be very good.
The general contractor in charge of the Roundhouse Park, Toronto (opening May 29-30) used a GPS unit about 8 inch square on a 5 foot stick which would lock in the position, by trigger, of the pointed tip within 5 cm (2 inch) but they are paying several thousand dollar a year for the subscription.

Think about it; once that is built into our cars, not only will we be able to prove that the other guy veered into our lane, the local constabulary will also be able to send us the speeding fine on monthly revolving account.

We are getting very close to 1984!

 

[bassfisher6522]

In February 2008 Google switched to updated maps and in the process moved my street address six houses over and across the street.
The satellite coordinate had not changed except that the winter shot of my pool now was a brilliant summer shot.Think about it; once that is built into our cars, not only will we be able to prove that the other guy veered into our lane, the local constabulary will also be able to send us the speeding fine on monthly revolving account.
We are getting very close to 1984!

Thanks, I'm glad I am not the only one with the same problem. After spending a few hours going through the forum threads I didn't see anyone with a similar problem.....I was getting a bit worried it was just me, my house or my tom tom. Thanks for clearing that up.

So right your are with the techno police. Pretty soon we will be getting tickets for sneezing while driving. I'm just waiting for the big brother aspect with the eye cam built in to these GPS units.....that's going to get the fire burning really hot.....like you said, it's just a matter of time....

 

[smokee]

What date set do TOMTOM XL use

Hi

I am new to the forum and to GPS but for a project at work we are checking GPS on a journey planner. The LAT/LONG that has been supplied are differant to the ones that my tomtom gives me when i am out in the field

The tec tell me that i am using a differant "Data set"

is tom tom using WGS84 or GDA94 ??

Smokee

 

[canderson]

Hi

I am new to the forum and to GPS but for a project at work we are checking GPS on a journey planner. The LAT/LONG that has been supplied are differant to the ones that my tomtom gives me when i am out in the field

The tec tell me that i am using a differant "Data set"

is tom tom using WGS84 or GDA94 ??

Smokee

Your TomTom uses WGS84. However --- some models at some firmware levels report a "road snapped" set of coordinates when you are on the satellite page and looking at coordinate data. "Road snap" is the feature that attempts to place you on the nearest road so that it doesn't look like you're having an 'off road adventure' when the geolocation of the road in the map data isn't perfect. It will keep trying to locate you 90 degrees to the nearest road until you're several hundred feet away.

Please advise which model you have. We may also need to have you report your firmware level. Anything running a version 8.XXX will report the snapped coordinate data.

A side note: GDA94 and WGS84 assumptions assure that the coordinates will be no more than 1 meter apart anyway. My guess is that you're seeing a snap condition, but do report back.

 

[Andy_P]

some models at some firmware levels report a "road snapped" set of coordinates when you are on the satellite page and looking at coordinate data.

That's a new one on me.... I know your "car cursor" location snaps to roads (that's on ALL models AFAIK), but I always believed the coordinates returned on the "Browse map" screen were always exactly the centre of the blue cursor, and that the blue cursor could be placed anywhere (within finger tapping accuracy!)

Any idea which are the software versions and models do it differently?

 

[canderson]

That's a new one on me.... I know your "car cursor" location snaps to roads (that's on ALL models AFAIK), but I always believed the coordinates returned on the "Browse map" screen were always exactly the centre of the blue cursor, and that the blue cursor could be placed anywhere (within finger tapping accuracy!)

Any idea which are the software versions and models do it differently?

Navcore 8 lied. Navcore 9 returned to reporting real coordinates again. This is what made Navcore8 units pretty useless for geocaching anywhere near a road, and was one of the two things that drove the 3rd party people crazy for a while.

 

[Andy_P]

Many thanks canderson. I learn something new every day! :thumb: