title: Use of scipy.interpolate.griddata for interpolation of data of multiple dimensions from xarray
body: <p>I have a rainfall data as xarray <code>DataSet</code> named <code>ds</code> of three dimensions <code>longitude</code>, <code>latitude</code> and <code>time</code>:</p>
  
  <pre><code>&lt;xarray.Dataset&gt;
  Dimensions:    (latitude: 691, longitude: 886, time: 1)
  Coordinates:
    * longitude  (longitude) float64 112.0 112.0 112.1 112.1 ... 156.2 156.2 156.3
    * latitude   (latitude) float64 -9.975 -10.03 -10.08 ... -44.42 -44.47 -44.52
    * time       (time) datetime64[ns] 1980-01-03
  Data variables:
      RAIN       (time, latitude, longitude) float64 0.0 0.0 0.0 ... 0.0 0.0 0.0
  </code></pre>
  
  <p>I would like to interpolate the rainfall values against another sets of longitudes and latitudes: <code>EXAMPLE_FFDI_LON_XR_DA</code> and <code>EXAMPLE_FFDI_LAT_XR_DA</code>. They have completely different values than the longitudes and latitudes of <code>ds</code>.</p>
  
  <p>EXAMPLE_FFDI_LON_XR_DA:</p>
  
  <pre><code>&lt;xarray.DataArray 'longitude' (longitude: 193)&gt;
  array([140.8    , 140.84792, ... ...], dtype=float32)
  Coordinates:
    * longitude  (longitude) float32 140.8 140.84792 140.89584 ... 149.95209 150.0
  Attributes:
      latIntersect:         0.0
      lonCentre:            145.4
      units:                degrees_east
      projectionType:       MERCATOR
      _CoordinateAxisType:  Lon
  </code></pre>
  
  <p>EXAMPLE_FFDI_LAT_XR_DA:</p>
  
  <pre><code>&lt;xarray.DataArray 'latitude' (latitude: 106)&gt;
  array([-39.2     , -39.149525, ... ...], dtype=float32)
  Coordinates:
    * latitude  (latitude) float32 -39.2 -39.149525 -39.09905 ... -33.950478 -33.9
  Attributes:
      latIntersect:         0.0
      lonCentre:            145.4
      units:                degrees_north
      projectionType:       MERCATOR
      _CoordinateAxisType:  Lat
  </code></pre>
  
  <p>I thought of using xarray <code>xarray.DataArray.interp</code> function but this only supports the <code>nearest</code> method. I am new to scipy but thought it would better suit my need to interpolate using the scipy library <code>scipy.interpolate.griddata</code> function. How can I go about using this function with my data? A working example would be helpful.</p>