Steve Ratcliffe wrote:
On Wed, Apr 08, 2009 at 07:36:09PM +0200, Bernhard Heibler wrote:
Is there anybody who wants to join me in understanding the MDR file ? I did already some research on the MDR file. Most of the sections I have not decoded until now. The MDR file has about 20 mysterious sections. What I found out so far is that we need at least 7 sections to enable the Nuvi address search. I found this out by removing section by section out of the header of a working MDR file. I have added some code to libgarmin to display some sections of the MDR. I'm able to decode some parts of the city, street and region index.
Have you looked at the MdrDisplay program in the display svn: http://svn.mkgmap.org.uk/display/trunk/src/test/display/MdrDisplay.java This contains everything I know about the format. Hopefully you can add to that knowledge.
Might I suggest everyone contributes info to the wiki? I just created a page for the IMG file as a whole, and I intend to seed it with info from John Mechelas's 2005 document, then add in all the other info I can find to try and fill in the gaps - it's here: http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/IMG_File_Format You'll see that although it hardly contains any useful info yet, it mentions the sorts of subfiles contained inside the IMG file, and I created a placeholder page for the MDR subfile too. Currently, that page is even more useless than the IMG page (:-)), but it will grow if anyone thinks (as I do) that this would be a good way to aggregate info as the file formats are reverse-engineered. Stone Soup and all that jazz... ( I'm making use of the "wikitable" class in order to keep the formatting of the info under some sort of control and with a similar "look and feel" across the pages as they grow (if they grow). You may know a better method, but this one seems to work OK for Wikipedia. ) Hope it proves useful Steve