Elevation Data not projecting correctly

dinoldinol Global Mapper UserPosts: 5
edited May 2009 in Technical Support
I have imported gravity data in er mapper format from the Satellite Geodesy, IGPP, SIO, UCSD | Radar Altimetry | Marine Gravity from Satellite Altimetry website. This data grid is for the whole world.It uses a mercator, lat/long, wgs84(I think) co-ordinate ref system.
However the grid longitude values appear to go from 0-360 degrees, not -180 to +180 and the resultant display shows 1/2 the world displaying in the "correct" position ie 0 to +180 deg the eastern hemisphere. The rest of the data is displayed to the right of the eastern hemisphere data and not wrapped around to the western hemisphere as expected. It falls in a "co-ordinate out of range" area
Could you please advise how I can import the data so both eastern & western hemispheres are positioned "correctly" so I can overlay coastlines and other data


  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited May 2009

    What you have to do is load the image twice, and then reposition one of them and shift it in the X direction by the negative of the world Mercator 360 degrees (-40030174.08 meters). I have attached a workspace file where I have done this to get the entire world to show. Just save the workspace in the same folder as your data and then load it.

    Let me know if I can be of further assistance.


    Global Mapper Support
  • dinoldinol Global Mapper User Posts: 5
    edited May 2009
    Thanks Mike
    I set the false easting at 40030174.08 and all the data is now there.
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