[Talk-ko] Blue oval signs are trunk roads- I think.

[Andrew Errington]

Hi everyone,

It has been some time since we discussed road classification, but I think it 
is still necessary.

On my most recent trip I noticed something which 'completed the puzzle' in my 
mind.

In Ganggwondo region there are a number of 'oval-signed roads' which have been 
upgraded to motorway status.  They are motorways, but they are not marked 
with a blue shield and they are not toll roads.  Bicycles are not permitted.

I have always thought that blue oval signs (with numbers in the middle) should 
be highway=trunk.  The original Korean tagging guide indicated there was no 
use for highway=trunk.  However, when I looked at these roads in real life it 
seemed to me that they should be trunk.  In fact, it seems to me that 
classifying Korean roads in general should be easy, because it's already been 
done for us by the government- just look at the sign.

Here is a list of sign types I have found, with useful descriptions:

<http://commons.wikimedia.org/wiki/Category:Road_signs_in_South_Korea>

Anyway, if we map a blue-oval road (Korean National Route) as highway=trunk 
then it's easy to 'upgrade' it to motorway.  We simply add motorroad=yes.  
Mapnik doesn't draw these sections differently, but Osmarender does.

Similarly, the hexagonal/octagonal signs can be
highway=primary
motorroad=yes

I am not sure about the difference with the red flash at the top of this sign 
(i.e. Korean Metro Expressway (red flash) and Korean Metro Route (no flash)).  
Comments please.

I have just finished adding a lot of detail for hwy 12 from Geochang to Daegu.  
I drove on that route when returning a rental car and we took a lot of 
photographs of bridges, number of lanes, speed limits, etc.  Sadly I could 
only do this in one direction.  When hwy 12 ends and joins hwy 451 at Daegu 
it's a big mess.  There has been a lot of road construction there.  It has 
recently finished though, so we can start sorting it out.  Unfortunately 
Yahoo! aerials are no good because they don't show the new construction.  I 
hope that mappers near Daegu can take a look.

Best wishes,

Andrew