Are there really no drawbacks at all to switching to Australian?

You have to top up the radiator with lager

Sorry I'll get my coat

Why is sat nav only accurate on a flat road?  Does the elevation of the road make a difference?

 

It isn't the elevation, but the variation in elevation.

 

Are there really no drawbacks at all to switching to Australian?  Would a friendly dealer be able/prepared to do it?

 

Very unlikely to get a dealer to do it.

Not sure if their equipment can.

Why is sat nav only accurate on a flat road?  Does the elevation of the road make a difference?

If you remember your Pythagoras from school, the GPS is calculating speed from the 'adjacent' side (of the triangle created by the road surface, the height change and the horizontal distance) but you're driving along the 'hypotenuse' which is longer. If my man maths is right that means it will under-read.

If you remember your Pythagoras from school, the GPS is calculating speed from the 'adjacent' side (of the triangle created by the road surface, the height change and the horizontal distance) but you're driving along the 'hypotenuse' which is longer. If my man maths is right that means it will under-read.

 

Actually did a bit of reading up on this earlier and you need to think of it in 3D, you are effectively determining your location inside a sphere.  If you just had the satellites and took away the Earth, then you would be able to get a really good fix on your position as you would have satellites all around you. But as the Earth gets in the way, the satellite picked up by your sat nav are all effectively above you, thus you can determine your horizontal position more accurately than your vertical position - you can work out where you are on a plane but not the exact level of the plane.

 

It would appear that the error on the vertical position is 1.5 times the error on your horizontal position.  Thus whatever error there is on your horizontal velocity increases as soon as you add a vertical component to your movement.

To my knowledge, GPS does not incude the resultant distance covered as a result of the vertical component, only the horizontal distance, i.e. you are actually travelling further along the road than the GPS thinks you are. GPS is typically +/-10m accurate horizontally (somewhere in a box of 400m2) if it's less accurate vertically this will increase the error hugely and compound the inaccuracy I've described.

I understand how GPS works; two satellites intersect to place you on a circle and a third dissects this circle giving two possibilities, one is your location and the other is way off in space or inside the globe so is disregarded. A fourth satellite is needed to give the altitude. A DGPS system with a fixed point at a known location increases the accuracy considerably.

But that would be fine if say each satellite 120° from the other, but as the earth vastly reduces the angle at which you can see the satellites so you need 4.

Sent from my Nexus 4 using Tapatalk

Never mind all this intellectual discussion  , the fact that 30mph is between 20mpg and 40mph etc, but it's much easier for a lot of people to see 32mph in a split second glance rather than calculating your speed or surmising.

It's nothing to do with accuracy either, more a convenient signal to the brain.

 

I can't talk, as I'm expecting a speeding ticket next week, the first ever, for speeding in a line of traffic at over 70mph on a dual carriageway   

Gizmo68 changed my maxidot over to the big MPH display just a week ago and I'm really grateful. I find it very much easier to use. I really can't see why dealers arent allowed to do this - but then I can't see why it's not specified as a standard by SUK. As others have said, you can very easily change the display back if you want to or need to. But then, I also don't understand why the speedo is in MPH only. Can't remember any other make of car I've had where this is the case.

Just to annoy everybody. I like my displays. Yes it does go 20, 40, 60 in mph, but I know that 30 is inbetween 20 and 40 because I can count.

The kph in the maxidot I also like as I spend a few weeks each year in France.

 

Am I alone in this view?

 

Colin

Not alone no, but seeing as it takes a few seconds for the KPH to reappear I imagine you are certainly one of the minority.

 

As has been said many times before you do not LOSE anything with the change, you simple gain the MPH option. 

^^ no and I live 'a la frog' - perhaps I should look for a large maxidot in kph ; - ))

So I will resurrect this post as I would like the digital mph display.

Having read all 4 pages of this thread I believe I need to find someone with VCDS - how do I do that?

 

There is a section in another part of this forum that lists all those who have volunteered their help. Think it is called VCDS Owners and Map or something similar.

Edited 17 June, 20196 yr by Llanigraham

How about getting the Carista OBD2 Bluetooth Adapter for £15 off Amazon and doing it yourself.

It gives you 1 month of the pro features that let you get a MPH display and lots more things.
All you have to do is cancel the pro features before the month is up (and Amazon sends an email reminding you to do that) and you are still left with an excellent OBD2 adapter.

1 hour ago, Urrell said:

How about getting the Carista OBD2 Bluetooth Adapter for £15 off Amazon and doing it yourself.

It gives you 1 month of the pro features that let you get a MPH display and lots more things.
All you have to do is cancel the pro features before the month is up (and Amazon sends an email reminding you to do that) and you are still left with an excellent OBD2 adapter.

 

That sounds like a good plan, will see what my brother thinks as he would be the one backing me up if I did this.

Thanks for the idea Urrell.

13 hours ago, Llanigraham said:

There is a section in another part of this forum that lists all those who have volunteered their help. Think it is called VCDS Owners and Map or something similar.

 

Found it and contacted the one nearest to me.

Thanks Llanigraham.