[mkgmap-dev] Reduce road class/speed when road is narrow

Tue Oct 13 12:47:59 BST 2009

Mark Burton wrote:
>
> The OSM wiki says:
>
> Describes the width of a way or other map feature. The unit is meters unless otherwise specified.
>
> Why didn't they say "the unit is meters" and leave it at that.
> Completely mad.
>
>   

Agreed - we've got the worst possible scenario currently.

What *should* have been done IMHO is that the OSM editor software 
(potlatch, JOSM, maybe others) could have allowed for widths and heights 
and speed-limit to be input in silly units, but that they would be 
converted locally, and be submitted to OSM in SI units as you might expect.

Users could then be able to set 'preferences' for their editor 
software's default behaviour (and then to forget about it), and no-one 
dealing with OSM data downstream would ever know that they'd originally 
entered the height limit in cubits, or the weight limit in short tons or 
the speed limit in furlongs per microfortnight! :-)

Such a change to OSM's database and the editor tools could still be 
accomplished with a bit of effort, with a robot written to trawl 
existing data and rewrite it to SI units. ( Please note that 
speed-limits should be in m/s if you're being pedantically SI-compliant, 
and weight limits in kg, not tonnes. )

Steve

PS: Some US users might well have been entering weight limits in the 
"wrong" ton(ne)s already, though the percentage difference between long 
tons and tonnes is only slight. What sort of tons do they put on US 
bridge weight limits warning signs anyway?