Global Mapper Pro

Problem with .gtx files and overall understanding of the whole matter

Prom
Prom Global Mapper User
edited December 2012 in Elevation Data
Good evening everyone,

Im currently looking into some files. This whole stuff is about game developement ( I know im kind of completly wrong in this forum for that matter ), to be accurate about terrains, tiles, heights, coordiante systems, positions, vectors, directions and so on. So basically everything needed to build up a proper 3D world. I already searched in magic google for like four days but hell i cant find any fitting answer and i downloaded like thousand programms already. I guess i just lack the knowledge...

Well, to the problem. I do have a heightmap in form of a .raw file. No problem. I now do have a layer (.lay) file given which seems to store some textures ( seen in hex editor, cant open it tho ). And other than that a folder containing .ilc files and several .gtx files. The map seems to be build up with a raster of 8x8 fields ( called polygon?? ), those fields seem to be represented by the .ilc files since the numaration is from 0-0 to 7-7 so 8x8 files. I assume that those files correspond to some kind of texture stored client sided or hold some data . And a changing number of .gtx files from map to map. I guess ( but i dont know, thats what im asking ) that those files hold some data of directions, vectors, maybe points or heightlevels of the map, i seriously dont know. But what i know is that, when opening it with a hex editor, the first lines say "geo" from which i came to the assumption that it has something to do with "vertical datum shift". Anyways i cant open those/that file so i wanted to ask if some knows an answer to this. Other than that a explanation of this .gtx file case would be great.
By the way, i already tried to open it with GDAL but for some case it say wrong dimension 1 x -1 something.

I attached examplefiles for each, .ilc, .lay and .gtx. (The forum uploader doesnt support those file extensions, im sorry :/ )

Thanks in advance ;)

Comments

  • global_mapper
    global_mapper Administrator
    edited November 2012
    What application does the .gtx format come from? That isn't a format that Global Mapper supports.

    It sounds like the data is maybe just gaming engine terrain and texture data and not actual geo-referenced mapping data for the real world, but I'm not sure about that. The GDAL documentation indicates the .gtx files are for vertical datum shifts, but that is almost certainly not something you would need in a game environment, so I'm guessing your .gtx files are something completely different.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • Prom
    Prom Global Mapper User
    edited December 2012
    Infact that were my first thoughts too. But the researches i done show an other side. Its like this, i got a .lay layer file with those .gtx file pathes stored inside and a seperated folder with .ilc and .gtx files. Like i explained, the raster seems to be 8x8 and i now thought that the .gtx files seem to display some data for the height levels of some 3d enviroment. And as i assume the vertical datum shift is something in the direction of high level geo referenced data? Anyways, the fact why i came to the conclusion it could have something to do with this is the header of the files showing the keyword "geo" in the hex editor. It could be an other kind of graphic too, that would need me to do another set of closer researches on the grafic matter.
    But anyways, thanks. Maybe theres a chance you find an answer :D:D
  • global_mapper
    global_mapper Administrator
    edited December 2012
    The vertical datum shift files would be used to translate data from one vertical reference system to another. But they wouldn't really be useful in a game environment which would want the actual elevation values at a location and not some translation between vertical reference models as those will just have values typically +-50m for every location on the earth and not actual values for the surface height at that location.

    The 'geo' text in the header could be some kind of projection reference indicating that the coordinates in the file are lat/lon values, or it could be something completely unrelated. I did find that there is a texture image format with the GTX extension used by Genetica software (http://www.spiralgraphics.biz/viewer/about_gtx.htm). Perhaps that is what these files are.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • Prom
    Prom Global Mapper User
    edited December 2012
    Well okay that really doesnt seem to make sense. Anyways, i already tried to open it up with genetica, that was acctually my first thought of what the files could be but infact it doesnt work.
    From what i know the only way .gtx files are used at geo referenced datasystems is for vertical datum shifts so kind of longitude/latitude data/values seems kind of unlikly, aint it?
    But i think ill have to do some other research on the texture matter since it would fit to the whole concept the best now.

    Thanks! :)
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