Global Mapper v26.0

V11 Beta3 - Exported Vertical Mapper Grid cannot be analysed properly in MapInfo's VM

gm_user1
gm_user1 Global Mapper UserTrusted User
edited December 2009 in Bug Report
It is great to see the new export function for Vertical Mapper grid format.

Export function is OK and the new grid can be displayed in MapInfo or MapInfo's Vertical Mapper environment.

But when using the Vertical Mapper's tools (such as Grid Info, Cross Section) interrogating the grid exported from Global Mapper, error messages pop up, such as

"Error in Show GridInfo: Unrecognized command: units"
"Unrecognized command: units"

In fact, all those units are there and recorded correctly. It appears the associated TAB file for the Vertical Mapper's grid is also OK. The only remaining guess would be for the GRD file exported from Global Mapper.

These errors occur in the latest version (V3.5) and the previous version (V3.1.1?) of Vertical Mapper.

By the way, is there a size limit for the exported Vertical Mapper grid? 4GB? It appears that Global Mapper can export to GRD file without any size limitation but Vertical Mapper can only load GRD file with the size less than 4GB.

Thanks.

Comments

  • global_mapper
    global_mapper Administrator
    edited August 2009
    That is strange, I'm not sure what would be odd about the units. Of course this format was reverse-engineered as MapInfo doesn't publish the format, so there could be something in there we don't know about. Do you have a GRD file that does work for those extra tools that you could provide so I can compare it to one that doesn't work?

    The main size restriction that I see is that the grid width and height values are limited to 16 bits a piece, which gives you a maximum of just over 4 billion samples, or about an 8GB maximum possible file size given there are 2 bytes per elevation sample. Of course Vertical Mapper might be limited to just reading a 4GB file for lots of other reasons.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • gm_user1
    gm_user1 Global Mapper User Trusted User
    edited August 2009
    Sample files sent.
  • global_mapper
    global_mapper Administrator
    edited August 2009
    Where were the files sent? I haven't seen them come into my email (support@globalmapper.com).

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • gm_user1
    gm_user1 Global Mapper User Trusted User
    edited August 2009
    Emailed it again. Also put the vm_grid.zip on the ftp site. Thanks.

    It includes two VM's grids - A is from the normal procedure based on VM's import with the ascii grid file, and B is from GM's new export function.

    It seems the ascii TAB files are OK, and problem is only with the binary GRD file generated. The file size of GRD file from GM is always 4 bytes smaller than that from VM.

    Also observed is that the GRD file exported from GM can be displayed in VM correctly, but the problem is still kept after re-projecting or re-sizing the exported GRD (from GM) in VM. Of couse, if we re-export the GRD file (from GM) to an ascii grid file in VM, and then re-import by using VM function, the problem will go away. So, something wrong with the binary GRD file exported from GM.
  • gm_user1
    gm_user1 Global Mapper User Trusted User
    edited August 2009
    Amazing - it has been fixed in the latest release. THANK YOU, Mike.
  • gm_user1
    gm_user1 Global Mapper User Trusted User
    edited December 2009
    For the latest V11.01 version and Vertical Mapper grid file exported, two issues are observed:

    1. The Vertical Mapper grid exported from V11.01 cannot be opened in MapInfo Professional again. It seems the Vertical Mapper grid file has got some modification in V11.01 production, athough the associated TAB file is still identical to that from V11.00.

    2. V11.01 and V11.00 interpret a same Vertical Mapper grid file (with an associated TAB file) differently: showing the difference on PIXEL WIDTH and PIXEL HEIGHT (e.g., one is 25m the other 24.994), of course, affecting the corner coords as well. NUM COLUMNS and NUM ROWS are still the same.

    Thanks.
  • global_mapper
    global_mapper Administrator
    edited December 2009
    Can you send your grid created with v11.00 that works and the one from v11.01 that does not so that I can compare them? I wouldn't expect any difference in the output format from v11.00 to v11.01.

    The interpretation of the coordinates was changed from v11.00 to v11.01, although we aren't extremely confident about the change as the Vertical Mapper format is not publicly documented so we are just guessing. Is the 25m spacing fromv11.00 and the 24.994 from v11.01?

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • global_mapper
    global_mapper Administrator
    edited December 2009
    I had another report of the spacing and alignment of Vertical Mapper being wrong in v11.01, so I've switched it back to how it was done in v11.00, which seems to have been correct. I have placed a new build at http://www.globalmapper.com/global_mapper11.zip with the change for you to try. Simply download that file and extract the contents into your existing v11.xx installation folder to give it a try. If you are using the 64-bit version, there is a new build available at http://www.globalmapper.com/global_mapper11_64bit.zip .

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • gm_user1
    gm_user1 Global Mapper User Trusted User
    edited December 2009
    Many thanks. All has been fixed.

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