Steve Ratcliffe wrote:
It looks like you can create a file with only the sections: 1, 4, 5, 6, 7, 11, 15. I shall start off with a header size of 286.
MDR 1: A reverse index from maps to the other sections. MDR 4: poi types, partially known MDR 5: Cities MDR 6: unknown, wiki claims it is a list of cities but I don't believe that
I wrote that bit of the wiki, and for me at least it's true. This is deduced from an NT map, with a record-length of 3 bytes. I wrote a program to grovel the MDR file, comparing MDR5 with MDR6 and it all panned out over something like 14000 entries. A bit of a fluke if the underlying assumptions weren't true!
MDR 7: Street names, optional as may be no streets MDR 11: POI's MDR 15: Strings
MDR 1 points to a subsidiary header for each map, there are at least 8 subsections in this header, some of which I partially understand and I expect that all of them lead back into the other sections.
NT maps (with MDR1 using a record-length of 4 bytes) seems to be listing the GMP subtile files. I hear that there are 8 bytes variants - don't know about them. It sounds like a good idea at least to try generating MDR files though - go for it! Steve