At 23:19:40 on Tue, 12 Feb 2008 Tom Anderson opined:-

On Tue, 12 Feb 2008, Neil Williams wrote:

On Tue, 12 Feb 2008 05:02:55 -0800 (PST), Mizter T
wrote:

I've never really used a sat-nav system to compare true speeds with
indicated speeds, so I've never really been aware of the difference
between the 'true' speed I've been travelling at as opposed to the
'indicated' speed.

Be careful if you do use a sat-nav. If you're going up or downhill,
it will read slower because (so far as the satellites can see) you've
slowed down because your speed has a vertical component as well.

Unless your box is using the height it's inseparably calculated in
determining your speed!

If it was, it could tell you the gradient you're climbing, too.

Since we're here talking sat-navs and speed limits, and since sat-navs
have maps, measure speeds and know about speed limits, are there any
which issue a warning when the local limit is being exceeded?
--
Thoss