[mkgmap-dev] splitter, mapid

Mon Dec 17 14:17:07 GMT 2018

Hi,

basically map ID should be unique for all tiles, regardless of FID. If 
you load 2 tiles with the same map ID to a GPS, it will silently ignore 
one of these tiles. Most probably GPS assume, that these are the same 
tiles and there is no reason to process both.

Search index contains map ID. If you use 2 maps with repeated map ID, 
then most probably search won't work correctly.

There is no problem with map ID in Basecamp or Mapsource, these programs 
don't support multiple maps.

I suggest to link map ID with FID using following formula:

First map ID in a mapset = FID*2048 + 6316032

Or in hex:
First map ID in a mapset = FID*800h + 606000h

This formula assigns 2048 IDs for each FID. It should be true also for 
original Garmin's maps, except for City Navigator series.

Gerd, maybe you could include these formula into splitter? Something like:
;--fid=27795
:  Calculate mapid basing on a FID value. Can be used instead of 
--mapid. Splitter sets first mapid value as 2048*fid + 6316032

-- 
Best regards,
Andrzej