Hi Andrzej, good to know. I assume the 16MB limit makes sense for other subfiles which only have 3-byte offsets. In DEM files every offset is stored with up to 4 bytes, so it it obvious that more than 16MB are intended. I've now found that there is already a method setMaxSize() which allows to set a different size and I am now testing the created img files. With gmapi format it looks good. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej@poczta.onet.pl> Gesendet: Freitag, 22. Dezember 2017 18:50:31 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] DEM size in Garmin Basemap > 16MB Hi Gerd, I have added DEM to my maps using BuilDemFile and without any changes to splitter parameters. The biggest DEM was about 35MB and the biggest img about 40MB including 32MB of DEM. I haven't noticed any problems. Even more, I have build TDB using test version of mkgmap v3999, so mkgmap has no problems with reading big img with DEM. I think there is no superficial limit for single img. Internal structure of img is FAT-alike, and limits comes from this structure. You can get 256 FAT records for a subfile like DEM and 240 sector pointers in each record. With max sector size 64kB, it makes limit like nearly 4GB. I don't know if mkgamp uses fixed sector size for created img. If yes, then limit would be dependent on this value. -- Best regards, Andrzej _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev