Reproject from known to unknown coord syst

STHSTH Global Mapper UserPosts: 434Trusted User
I have a problem. I need to re project form a known system UTM32 WGS84 to an unknown system UNKNOWN. I have the same vector data in both systems. And the raster data is in a known system. I am trying to use the Batch Image rectifier and http://www.globalmapper.com/helpv9/Help_ImageRectification.html.

I guess I have to add a UNKNOWN Projection on the "Select Projection" dialogs box, however I do not know the parameters.

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited December 2007
    If I understand correctly, you have a raster in a known UTM system and some vector data in an unknown system, and you need to get the raster data into the unknown projection system that the vector is in. To do this, first just load your vector file and just accept the default projection since you don't know the actual projection. Then, use the File->Batch Rectify menu command to load your imagery file and rectify it to match the vector data. Since you don't know the actual projection used, just accept the default.

    Once you are done the raster should match the vector and use the same coordinate system. The only thing missing is that the lat/lon readout on the bottom will be incorrect since you don't actually know how to define the unknown projection system that the coordinates are in, but I'm assuming this is ok with you. If not you'll have to find out the parameters of the unknown projection system from your data provider.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • STHSTH Global Mapper User Posts: 434Trusted User
    edited December 2007
    Yes you have understood correctly. The Data provider does not want to provide me with the transformation parameters, only the correct vector-data in the new coordinate system. So I know that the coordinates in the unknown system is the "correct answer" and have to match my raster data as close as possible.

    In most cases the correct coordinate system is close to NGO I - VIII, but with some rotation,translation, scaling that differs.
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