.. highlightlang:: us

.. index:: griddata

.. _griddata:

griddata
========

.. us.tag  griddata ENGLISH interpol-2d New5200

:ref:`griddata` creates a regular grid of arbitrarily distributed data triples.

.. function::  rmZi = griddata(rvX, rvY, rvZ, rvXi, rvYi)
    rmZi = griddata(rvX, rvY, rvZ, rvXi, rvYi, nOption)
    rmZi = griddata(rvX, rvY, rvZ, rvXi, rvYi, ssOption)

.. us.return

**Return Value**

*rmZi* is the interpolated z value matrix for the given *rvXi* and *rvYi* 
coordinates. In case of an error *rmZi* is an error object (see example).

.. us.params

**Parameters**

.. uparam:: rvX
   
   *rvX* is a real vector with at least 4 elements.
   

.. uparam:: rvY
   
   *rvY* is a real vector with at least 4 elements. The number of points must
   be identical with *rvX*.
   

.. uparam:: rvZ
   
   *rvZ* is a real vector with at least 4 elements. The number of points must
   be identical with *rvX*.
   

.. uparam:: rvXi
   
   *rvXi* is a real vector with at least one point. 
   

.. uparam:: rvYi
   
   *rvYi* is a real vector with at least one point. 
   

.. uparam:: ssOption
   
   See *nOption*.

.. uparam:: nOption

   Is one of the following values:

   .. list-table::
      :header-rows: 1

      * - ssOption
        - nOption
        - 
      * - "linear"
        - 1
        - Linear interpolation.
      * - "cubic"
        - 2
        - cubic spline interpolation.
      * - "tps" oder "thin-plate-spline"
        - 3
        - Thin-Plate-Spline interpolation.
      * - "poly1" or "plane"
        - 4
        - 
      * - "poly2"
        - 5
        - 
      * - "poly3"
        - 6
        - 
      * - "interp1d-bilinear"
        - 7
        - 

.. us.example

**Example**

If an error occurred, :ref:`griddata` returns an error object (see also
:ref:`error_create`). 

::

   def test_griddata()
   {
       srand(1);
       x = rand(100, 1)*15-7.5;
       y = rand(100, 1)*15-7.5;
       r = sqrt(x.*x + y.*y);
       z = sin(r)./r;
       xi = linspace(-7.5, 7.5, 40)
       yi = xi;
       zi = griddata(x, y, z, xi, yi, "thin-plate-spline");
       if (type(zi) == "error") {
           MessageBoxError(zi.message);
           return FALSE;
       }
       plotxyz(xi, yi, zi);
       return TRUE;
   }

.. us.history

**History**

.. list-table::
   :header-rows: 1

   * - Version
     - Description
   * - 5.20
     - New.

.. seealso::
   :ref:`overview-mathematic`,
   :ref:`fspline2`,
   :ref:`smooth2`,
   :ref:`XYZGetInterpolationType`

:sub:`id-1546570`