In your letter dated Sat, 11 Oct 2008 12:57:18 +0100 you wrote: >In the UK with bridge heights there isn't an exact conversion factor - >mainly because a signed 11'3" bridge isn't 11'3" high. To get the signed >height - you subtract 3 inches from the true height then round down to the >next 3 inches. There will always be between 3 and 6 inches leeway. > >When a UK bridge is signed in metric as well, you don't convert the imperial >measure. You subtract 0.08m from the correct height measured in metres - and >then round down to 1 decimal place. Thus the actual leeway will be between >8cm and 18cm.
Isn't that just conservative engineering? You make sure that any verhicle that is at most the posted height can pass safely, and when a verhicle does hit the ceiling, you know that it was not a just a tolerance issue. There is no need to make use of that information unless you actually have to (if there is no other way of reaching a destination) I guess that for routing you want to take the higher imperial heigh into account and put the metric value in a comment section. Do people actually enter 11'3" in a consistent way when tagging heights? _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
