[mkgmap-dev] MDR6 description in wiki

Thu Aug 11 14:52:56 BST 2011

On 08/06/2011 03:11 PM, WanMil wrote:
> Hi,
>
> my question is mainly directed to Steve Hosgood: You have added the
> description of MDR6 to the wiki
> (http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/MDR_Subfile_Format#MDR6_ShortForm_Gazetteer).
> In mkgmap the MDR6 is currently used for ZIP codes only. Do you remember
> how you gathered the information that MDR6 is a sorted list of cities?
> Maybe the MDR6 is more than a zip code list only.
>

Hi Wanmil:
I'll reply to the list in case anyone else wants to join in.

I've got a Garmin "NT" map for the UK that came with my Streetpilot. 
Most of it is encrypted of course, but the MDR subfile is not, and much 
of what I've contributed to the wiki was based on what I found when I 
looked at its contents.

What I claim for MDR6 is based on what I've seen, but of course it may 
be possible for MDR6 to have many alternative forms (probably governed 
by the "flags" word in the header). It could be that for my set of 
Garmin maps, they just were not using anything except the simplest 
version of MDR6.

Maybe other people with official Garmin maps could try pulling them 
apart to see what other variants exist out there.

Steve