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How To: Project data to a custom coordinate system with a non-Greenwich central meridian

Summary

Instructions provided describe how to create a custom projection with a non-Greenwich central meridian and apply it to a shapefile or feature class.

Procedure

These steps project the COUNTRY data set from ESRI Data & Maps to a custom Geographic Coordinate System with a central meridian of -180. This allows the whole Pacific Rim region of the earth to be displayed as one continuous region.

  1. Create a custom .prj file.

    A. In ArcCatalog, select Coordinate Systems > Geographic Coordinate Systems > World, and select the GCS_WGS_1984.prj file.

    If the Coordinate Systems folder is not displayed, go to Tools > Options > General tab, and check the Coordinate Systems check box in both the upper and lower windows.

    B. Right-click the .prj file and select Copy.

    C. Select Paste to paste the file into the same folder.

    D. Right-click the copy, select Rename, and name the file 'idl.prj'. These initials stand for 'International Date Line'. Another name can be used.

    E. Double-click the .prj file icon to open the projection file. The name must be changed in the Name box at the top of the dialog box. Use the same name that was assigned to the external file, but without the PRJ extension.

    F. Open the Datum drop-down list, and select <custom>.

    G. Open the Spheroids drop-down list, and select <custom>. Do not change the values shown for the semi-major axis, semi-minor axis, or inverse flattening ratios.

    H. At the bottom of the Geographic Coordinate System Properties dialog box, open the Prime Meridian Name drop-down list, and select < custom >.

    I. Change the Longitude value from 0 0 0 to -180 0 0 and click OK.

  2. In ArcToolbox, select Data Management Tools > Projections > Project Wizard (shapefiles, geodatabase).
  3. Browse to the data set COUNTRY. Notice the data projection is defined as GCS_WGS_1984. Click Next.
  4. Specify the output data set name and location. Click Next.
  5. Click Select Coordinate System. Navigate to the .prj file created in step one.
  6. In the Select Geographic Transformation(s) dialog box, click Set Transformation.
  7. Click the first New button in the Geographic Coordinate Systems Transformations dialog box.
    [O-Image] Custom geographic transformation
  8. Accept the default method Geocentric Translation, and the zero values for the three parameters by clicking OK.
  9. Click OK in the Geographic Coordinate Systems Transformations dialog box.
  10. Click Next in the Coordinates extents.
  11. Click Finish.
  12. Add the output data to a new, empty Data Frame in ArcMap.
  13. Right-click the Data Frame and click Properties.
  14. Select the Coordinate System tab.
  15. Click the Transformations button.
  16. Click New.
  17. Accept the default method Geocentric Translation and the zero values for the three parameters by clicking OK.
  18. Click OK through the rest of the dialog boxes to accept these settings.

    Note:
    New data added to this data frame will be projected on-the-fly to this custom coordinate system.

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