Thanks, i'll do some more testing. It was indeed a single zip with 17Gb hgt. Strange thing is that it for sure works with a 17Gigabyte single zip containing 26.000 mixed 1arc/3arc hgt files. (Windows 10) It still finds all files from New Sealand, to Zambia and Europe as long as it contains a subfolder in the zip. But don't bother, I did not take performance into account. And my tests where not that scientifically correct. Because of the huge sizes... I only tried only until it worked again. Kind regards Joris -----Oorspronkelijk bericht----- Van: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> Namens Gerd Petermann Verzonden: maandag 8 juni 2020 07:57 Aan: Development list for mkgmap <mkgmap-dev@lists.mkgmap.org.uk> Onderwerp: Re: [mkgmap-dev] Usage of DEM files within zip Hi Joris, I cannot reproduce the problem. I've created a srtm3.zip containing two files N52W003.hgt and N53W003.hgt and --dem=c:\temp\srtm3.zip works fine. My assumption: Your world-hgt.zip file really contained all hgt files and got larger than maybe 2G and the zipfile class in java cannot process it. mkgmap tries to support the file formats which are provided by the various DEM providers. I think I once tested performance with a large zip containing many hgt files and it was worse compared to single zipped files. IIRC the better alternative was to compress the folder with the hgt files (not using zip but the OS methods) or to have each hgt file zipped. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Joris Bo <jorisbo@hotmail.com> Gesendet: Sonntag, 7. Juni 2020 20:45 An: Development list for mkgmap Betreff: [mkgmap-dev] Usage of DEM files within zip Hi I struggled today with the DEM/hgt files in a zip. After downloading some extra and checking/rezipping finally my maps did not work anymore. I do not have the exact error anymore but it was clear: DEM HGT files not found Now it looks like if the ZIP does not have a folder but only the HGT files on the root of the zip then mkgmap does not recognize them If I rezip everything again and put the files within a subfolder first, it is oke. For me its fine, I solved 'my' issue, but if this is true it could better be in the manual or solved in code. Looks like this does not work: world-hgt.zip\N00E006.hgt world-hgt.zip\N00E007.hgt world-hgt.zip\N00E008.hgt And if I do it like this its oke world-hgt.zip\world-hgt\N00E006.hgt world-hgt.zip\world-hgt\N00E007.hgt world-hgt.zip\world-hgt\N00E008.hgt Kind regards, Joris Bo _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev