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Vectors and Mapping

If you insert a map projection into an iTool with an existing vector visualization, or if you insert a vector visualization into an iTool with an existing map projection, IDL will attempt to determine whether the vector visualization should be warped using the current map projection.

If the X coordinates of the vector visualization are in the range from -180 to 180 and the Y coordinates are in the range from -90 to 90, the locations of the vectors are assumed to represent longitude and latitude. In this case, the location of each vector is warped to the current map projection. If the X and Y coordinates are not in this range, the vector locations are not warped.


Note
The locations and directions of vectors are warped, but their magnitudes are not. The magnitude is assumed to be independent of the grid units.

You can override the default behavior by setting the Grid units property of the vector visualization or by specifying the value of the GRID_UNITS keyword to IVECTOR:

  IDL Online Help (March 01, 2006)