[Talk-GB] Speed limits

Nick Folwell nick.folwell2 at btinternet.com
Fri Sep 21 08:38:35 BST 2007

But surely it's useful to be able to display the local units, for a GPS
USER. My TomTom does this - in mph in the UK, and (I believe) kmph on the

So I can glance at the screen and see what the limit is, in the local
units... no conversion required.

Nick Folwell
nick.folwell at btinternet.com

-----Original Message-----
From: talk-gb-bounces at openstreetmap.org
[mailto:talk-gb-bounces at openstreetmap.org] On Behalf Of Mark Williams
Sent: 21 September 2007 08:17
To: talk-gb at openstreetmap.org
Subject: [Talk-GB] [Fwd: Re: Speed limits]

-------- Original Message --------
Subject: 	Re: [Talk-GB] Speed limits
Date: 	Fri, 21 Sep 2007 08:04:07 +0100
From: 	Mark Williams <mark.666 at blueyonder.co.uk>
To: 	Richard Fairhurst <richard at systemeD.net>
<002901c7fb64$94b834f0$0300a8c0 at DELLDESKTOP><68e55ace0709200202i2a6bf76jd3ca
b1d6da6f649e at mail.gmail.com><a4c775140709200229q7db52bc6q7e5acacfe2f232ad at ma
il.gmail.com><20070920104820.ckrnlcd9oo4gw008 at webmail.systemed.net> 
<a4c775140709200304t1cbed39vf61cab8f8787a57a at mail.gmail.com> 
<20070920113752.4170tpwi88k8swwc at webmail.systemed.net>

I read the thread; I really don't understand why we have to be difficult 
here, I use the kph values often;  we have a lot of odd limits round 
here (Thurrock) & so it needed doing. I had no great problem working out 
the metric...

Looking to map uses, we're going to be wanting routing, to know how fast 
a given route is; or a warning if over speed, from GPS (as nothing else 
knows our location..). So we will have software using it. Is someone in 
'foreign parts' going to know / care about us using mph? No, so we'll be 
the only people in the world who can't use their products! Does it 
matter if we get the speed warning in error at 29.825817mph instead of 
30? Really? Does it matter if it misreads it silently, and doesn't beep 
'til 48? Yup. What if the mph has a typo, does the s/w have to interpret 
pmh or kmph? It's worse for a maxspeeed_units=mph tag :)

I'm definitely against this idea!

For the record, I have no great urge to go metric ourselves; I just want 
things to work, and perceive a  point of failure in this. I realise that 
programmers can easily add a comversion routine - but why cause the 
problem? It's like the Millenium Bug - a bit of forethought would have 
prevented all the hoohah, and work to make it all OK - & we coped with 
that too, but can't we learn a lesson??

We could, I suppose, have an agreement that Planet gets parsed from time 
to time & converted to kph, so mappers can enter it as mph, if we really 


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