Name

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    BILIN_INTERP

Purpose

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    Performs bilinear interpolation for a function defined on a 2D grid.

Category

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    Math

Calling Sequence

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    Result = BILINC_INTERP(Z, X, Y, Xout, Yout)

Inputs

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    Z: 2D array containing the values of the function defined at each
          X,Y grid point. The first dimension of Z must have the same length
          as X and the second dimension must have the same length as Y.
    X: Vector containing the x-locations of the grid points at which
          the function is defined.
    Y: Vector containing the y-locations of the grid points at which
          the function is defined.
    Xout: A vector of x-locations at which the function is to be interpolated.
    Yout: A vector of y-locations at which the function is to be interpolated.

Outputs

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    A vector containing the value of the function bilinearly
    interpreted at each Xout,Yout pair. The output will have the
    same number of elements as Xout and Yout.

Example

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    IDL> xgrid = [1.,2.]
    IDL> ygrid = [2.,5.]
    IDL> zvals = [ [10.,2.], [25.,15.] ]
    IDL> PRINT, BILIN_INTERP(zvals, xgrid, ygrid, [1.3], [3.])
          12.4000

Modification History

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    Written by: Jeremy Bailin
    11 June 2008 Public release in JBIU