Change in accuracy with new maps?

agusta · Occasional Visitor Joined: Jul 06, 2008 Posts: 25

Is it just me, or is the positioning of the vehicle icon not quite as accurate on the new maps?
I recently downloaded the new maps on to my TT720 via Tomtom Home, and now it appears that the car icon on-screen is slightly out of "whack" compared to the view out of the window. For example, when travelling past a junction or side street I am past the turning just before the map catches up and shows the same thing. Conversely, when sitting at a T junction etc the screen shows my car as being over the other side of the road.
It doesn't seem to affect turn instructions etc, and it is only a few yards, it just seems to be in the map drawing - I seem to remember that before I updated the maps it was pretty much spot-on (although may be my memory is not what it was!).
Anyone else noticed this?
Incidentally, when I upgraded the maps I also installed the Tomtom "quick sat fix" option, so I suppose that could also be a possible factor.

mikealder · Posted: Tue Jul 22, 2008 9:23 am Post subject:

How often does the map screen re-draw, is it once per second or faster?

Also try disabling and custom POI files you have installed to the device, I have seen too many of these mess up the screen positional accuracy and slow down the re-draw speed - Mike

agusta · Occasional Visitor Joined: Jul 06, 2008 Posts: 25

Mike, the only poi's I have added are from the PGPSW camera database.
I would guess the redraw is about 1 per second or so (it does seem a bit more jerky than it was). Having tried it again yesterday I am now certain it is lagging behind (particularly noticeable on roundabouts), then, when stationary it seems to catch up and sometimes "overshoot".
Is there a sensible way of back-tracking what I have done so far (loaded new maps from TT Home, switched on the quick GPS fix, loaded PGPSW camera database), to try and single out where the problem might be - or any other suggestions?

andy-c1 · Posted: Thu Jul 24, 2008 8:15 am Post subject:

i found if you disable the poi's under browse map it does improve teh mapping
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Andy_P · Posted: Sun Jul 27, 2008 12:43 am Post subject:

I'm becoming more and more convinced that downloading the GPS Quickfix can screw up the display like this.
A few months ago there was a flurry of reports of the car cursor being upto about 200 yards off to one side of the road.
I still get this occasionally, and it is always just after I've allowed a Quickfix download.
It seems to cure itself over an hour or so.

agusta · Occasional Visitor Joined: Jul 06, 2008 Posts: 25

I am now at the point where it is advising me of the roundabout exit when I am already at it. Therefore I am having to look at the screen far more than I would like so it is becoming an issue for me.
How do I disable poi's (as mentioned above) without disabling camera warnings?
Is it possible to restore my unit back to a previous setting to see if I can regain the accuracy?

alanji · Posted: Sun Jul 27, 2008 3:56 pm Post subject:

agusta · Occasional Visitor Joined: Jul 06, 2008 Posts: 25

OK, thanks. I've done that, although if custom POI's means ones that I have added then I haven't (knowingly) added any apart from the PGPSW speed cameras.
Anyway, I'll try it next time I'm out and see if unchecking the POI's that were checked makes any difference.

Steveee · Posted: Mon Jul 28, 2008 7:53 am Post subject:

I noticed this as well:

Steveee · Posted: Mon Jul 28, 2008 8:05 am Post subject:

Oh yeah, at the same time I also noticed the receiver keep on switching to Enhanced Positioning Technology as it lost the satellites. This was quite worrying as I was on a motorway with clear view of the sky Crying or Very sad

As it quickly switched back, with full satellite coverage I was not too concerned.

Later on, driving in Netherlands the GO920 locked up. I suspected a memory problem (I was running blue tooth, connected to the mobile phone, TMC, FM transmitter and the latest maps (the use more memory)) so I removed the North America maps and switched off the FM transmitter. Since then no lock ups Very Happy

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kichu1979 · Regular Visitor Joined: Jan 29, 2008 Posts: 99

Calomax · Posted: Mon Jul 28, 2008 9:00 am Post subject:

My Go 720 also seems slower than my old IPAQ/TTN setup. I'm often at a junction while the display shows me still approaching. That's without having any POIs enabled to display on the map, which is something I never do.

Sadly whenever you look for a POI, the category you look for is automatically enabled so you always have to go back and deselect them again.
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falkirk81 · Posted: Mon Jul 28, 2008 11:07 am Post subject:

On a trip to aberdeen from newcastle last week, i noticed that my ttgo520 was running v slow. It appeared to not be a case of too many POI`s loaded, but more to do with the RDS-TMC.

It had several issues around edinburgh and then dundee and the background recalculation was slowing the thing down. I can only assume this was due to the length of the route and the time it took for each recalculation.
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kichu1979 · Regular Visitor Joined: Jan 29, 2008 Posts: 99

delete quickgpsfix folder from your device, ie. remove "ephem" folder on the device if you look under widnows explorer, and dont do any quickgps updates via home and see if it makes any difference

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