On Friday, 06 June 2014, at 16:08:24 +0200, Oliver Eichler wrote: > Thus even if a decoder honores the GMP section, it will fail to decode most > of the stuff in that section, > because unknown data containers are used. > I guess some context is necessary here for those reading the list archives quickly and for anyone outside Spain (which both mitxelin come from ;) ). Sorry for the off-topic.
We were fortunate enough in Spain that the public survey organization released years ago most vector data for topographic maps (including DEMs as precise as 5 x 5 meters horizontal, and 0.1 meter vertical), so there was one private effort the produced a set of Garmin-format GPS maps for the whole country, with unprecedent precision and detail, which ended up being called the infamous Topohispania (in contrast with Garmin's own commercial offering, called TopoSpain, available for purchase at the time). Firs initial releases for TopoHispania were plain Garmin format maps, which any compatible application , including QLGT, could open and fully utilize. But then, the typical Spanish genes came into play, and after some nasty disputes over someone "reusing" the free TopoHispania to sell variations of the same with routing enabled, the developers for TopoHispania started releasing new versions with routing, and in pseudo-NT format. Probably in a vague effort to put the other guys trying to make a living from someone else's work to death. Anyways, as soon as that happened, QLGT users could no longer use larter TopoHispania versions, as QLGT doesn't even try to understand the extended Garmin format. Pseudo-NT Garmin maps seem to be just a stupid internal reorganization of the traditional Garmin IMG subfiles within a new container called GMP. Real NT maps not only place the TRE, LBL, DEM, etc. subfiles inside a GMP subfile (instead at the top level of the IMG file), but include new (and yet to be reverse engineered) compression, that makes for real NT maps unreadable by anything else than Garmin official applications. What mitxelin refers to is there seems to be someone with the right skills and time that have produced working code that takes pseudo-NT files (that is, those just putting ages-old Garmin format subfiles in a GMP container, but not using proprietary compression) and manages to create working non-NT Garmin files that contain the same data. mitxelin seems to have tested it with the aforementioned TopoHispania (which includes DEMs and other stuff) and seems to work fine, after all, we are just talking about "extracting" regular Garmin subfiles and repacking them into a regular non-NT map file without getting in any of the subfiles at all. Of course, that's not me or mitxelin or anyone else asking for anyone else taking the time and effort to go through the pain of doing so in QLGT (the potential interested user base is small, and implementation could be quite harder than pre-processing each pseudo-NT file in the viewport to buffer some regular non-NT equivalent file, existing QLGT code can use as if the IMG had been a non-NT file existing on disk on the first place), but considering there may be people in the future reaching this email thread because their pseudo-NT maps won't load in QLGT, I thought it wouldn't hurt to go full circle and document what the findings were all about. Also, please note I am here expressing my understading of the technical issue and my very own interpretation of mitxelin's earlier email, so I may be wrong with either one of those, or both. Cheers. -- Jose Luis Domingo Lopez Linux Registered User #189436, Linux Ubuntu 12.04.4 LTS (3.2.0-63-generic-pae) ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/NeoTech _______________________________________________ Qlandkartegt-users mailing list Qlandkartegt-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/qlandkartegt-users
