dsgrid2

Interpolates gridded 2-D data.

Prototype

	function dsgrid2 (
		x  [*] : numeric,  
		y  [*] : numeric,  
		z      : numeric,  
		xo [*] : numeric,  
		yo [*] : numeric   
	)

	return_val [dimsizes(x) * dimsizes(y)] :  float or double

Arguments

A 1-D array of length (npts) containing the X coordinates of the input data.

A 1-D array of length (npts) containing the Y coordinates of the input data.

An array of any dimensionality (last dimension must be npts) containing the functional values of the input data. Element z(...,i) is the value of the input function at coordinate (x(i), y(i)) for i = 0, npts - 1).

A 1-D array of any length (numxout) containing the X coordinates of the output data grid. The values in xo must be increasing, but need not be equally spaced.

A 1-D array of any length (numyout) containing the Y coordinates of the output data grid. The values in yo must be increasing, but need not be equally spaced.

Return value

Returns a floating point array dimensioned as N x numxout x numyout, where N represents all but the last dimension of z. The return value type is double if z is of type double.

Description

This function performs interpolation from sets of 2-D random data.

This function requires that desired values for control parameters have been set using the procedure dssetp.

This function is part of the Dsgrid package which implements a simple inverse distance weighted interpolation algorithm. No missing values are allowed.

See Also

dsgrid2d dsgrid2s dsgrid3 dsgrid3d dsgrid3s dspnt2 dspnt2d dspnt2s dspnt3 dspnt3d dspnt3s dsgetp dssetp

Examples

Example 1

begin

  NUM = 6
  NX  = 61
  NY  = 61

  xi = (/0.00, 1.00, 0.00, 1.00, 0.40, 0.75/)
  yi = (/0.00, 0.00, 1.00, 1.00, 0.20, 0.65/)
  zi = (/0.00, 0.00, 0.00, 0.00, 1.25, 0.80/)
  xeye =  3.3
  yeye = -3.3
  zeye =  3.3

  xo = new((/NX/), float)
  yo = new((/NY/), float)

;
; Create the output grid.
;
  xinc = 1.0 / (NX - 1) 
  yinc = 1.0 / (NY - 1) 
  ii = fspan(0.0, 60.0, NX)
  xo = xinc * ii
  yo = yinc * ii
;
; Exponent equals 0.5
;
  dssetp("exp", 0.5)
  zo = dsgrid2s(xi, yi, zi, xo, yo)
end