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gobstopper
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Joined: Sep 17, 2005
Posts: 16
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 Posted: Thu Mar 17, 2011 7:49 pm Post subject: TomTom GO 750 - Compass Oddity |
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I've had my GO 750 unit for just over a week and, on the whole I am very pleased with it's performance.
However, I've discovered something which I can only put into the "strange" category. Just out of curiosity I've enabled the little compass which appears just above the section of the screen displaying the time and speed.
As far as North and South are concerned, it's quite happy. When it comes to East and West, however, everything is back to front. Traveling on the M4 this evening from Slough towards the M25 I couldn't be traveling more Eastbound if I tried. The compass on the 750 had different ideas and was resolutely pointing West! As soon as I got onto the M25 and headed clockwise (away from Heathrow) it quite correctly showed me going North(ish - give or take). As soon as I 'turned the corner' and was on the stretch from 18 towards 27 (my eventual exit) I was once again (according to the unit) traveling West.
Doesn't make any sense to me - can anyone enlighten? 
Phil. |
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Darren
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| Posted: Thu Mar 17, 2011 7:58 pm Post subject: |
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It does, and if you do a search you'll see it's been discussed many times.
See this thread as an example, AndyP explains it better than I can.
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Darren Griffin |
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Andy_P
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Location: West and Southwest London
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| Posted: Thu Mar 17, 2011 8:01 pm Post subject: |
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It's not wrong, but it seems to confuse an awful lot of people!
You just have to remember the compass needle ALWAYS points to the north, just like a real one sitting on your dashboard.
Got into quite an argument with someone once, so I did a drawing...
My house lies on a road that goes east-west.
In the first picture, I come out of the house, turn right and travel towards the east.
In the second picture, I come out of the house, turn left and travel towards the west.
EDIT: HaHa Darren beat me to it, but very happy he remembered my piccs! |
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gobstopper
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| Posted: Thu Mar 17, 2011 8:05 pm Post subject: |
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Thanks Darren - After 4 early morning starts, I just need to sanity check that what Andy_P is saying is that the point of the arrow on the compass will always point to North?
I think I've got it... So with me travelling due East, the pointer would (to the uninitiated, like me 2 hours ago) point "<" making me think that it's telling me that I'm traveling West, whereas it's actually telling me where North is.
That's going to take some getting used to, compared to my old copy of TT5 who's compass always pointed in the direction I was traveling. |
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Andy_P
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Location: West and Southwest London
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| Posted: Thu Mar 17, 2011 8:08 pm Post subject: |
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The full post Darren linked to was a bit of a "stream of consciousness"!
Use the picture above and just keep thinking about a real compass sitting on the dashboard too.  |
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Darren
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| Posted: Thu Mar 17, 2011 8:15 pm Post subject: |
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And whilst it may seem odd at first, once you understand how it works it does make sense.
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Darren Griffin |
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gobstopper
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| Posted: Thu Mar 17, 2011 8:15 pm Post subject: |
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| Thanks Andy - Much appreciated. |
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M8TJT
The Other Tired Old Man
Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK
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| Posted: Thu Mar 17, 2011 8:23 pm Post subject: |
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| gobstopper wrote: | | ....what Andy_P is saying is that the point of the arrow on the compass will always point to North? |
That's what magnetic compasses always do  The other end points south of course  |
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MrT
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| Posted: Thu Mar 17, 2011 8:39 pm Post subject: |
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But does the compass point to true north or magnetic north?
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Drivelux |
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Andy_P
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| Posted: Thu Mar 17, 2011 9:17 pm Post subject: |
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And of course the "North" end of a compass needle is actually a south pole!
(north attracts south and vice versa)  |
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mikealder
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Location: Blackpool , Lancs
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| Posted: Thu Mar 17, 2011 10:07 pm Post subject: |
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| MrT wrote: | | But does the compass point to true north or magnetic north? |
A True Compass will point to Magnetic North, a TomTom Compass will point to True North.....
Geeez, just re-read that and it somehow looks confusing......... - Mike |
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M8TJT
The Other Tired Old Man
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Location: Bexhill, South Sussex, UK
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| Posted: Thu Mar 17, 2011 10:16 pm Post subject: |
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| mikealder wrote: | | MrT wrote: | | But does the compass point to true north or magnetic north? |
A True Compass will point to Magnetic North, a TomTom Compass will point to True North.....
Geeez, just re-read that and it somehow looks confusing......... - Mike |
Surely it's a magnetic compas that points to magnetic north, a true compass will pont to true north And what about grid north on OSGB? |
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DennisN
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Joined: Feb 27, 2006
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Location: Keynsham
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| Posted: Thu Mar 17, 2011 10:19 pm Post subject: |
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| Andy_P wrote: | And of course the "North" end of a compass needle is actually a south pole!
(north attracts south and vice versa) |
No, Andy. The "north" pole is actually south - it attracts the North Arrow ends of compasses. 
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Dennis
If it tastes good - it's fattening.
Two of them are obesiting!! |
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mikealder
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Joined: Jan 14, 2005
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Location: Blackpool , Lancs
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| Posted: Thu Mar 17, 2011 10:25 pm Post subject: |
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| M8TJT wrote: | | And what about grid north on OSGB? |
That's what the Mag Var offset value is for printed on the OS Map so you can work it out using the map, although "Self Centered" maps don't have the Mag Var applied to them  - Mike |
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Andy_P
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Location: West and Southwest London
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| Posted: Thu Mar 17, 2011 11:38 pm Post subject: |
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| DennisN wrote: | | Andy_P wrote: | And of course the "North" end of a compass needle is actually a south pole!
(north attracts south and vice versa) |
No, Andy. The "north" pole is actually south - it attracts the North Arrow ends of compasses. |
Oh Gawd! I thought you were joking, but you're right!
http://www.tpub.com/neets/book1/chapter1/1g.htm third section down...
| Quote: | This magnetic pole is named the magnetic North Pole. However, in actuality, it must have the polarity of a south magnetic pole since it attracts the north pole of a compass needle. The reason for this conflict in terminology can be traced to the early users of the compass.
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