alid options are copy by index, set to special value,
nearest neighbor, nearest neighbor in "i" direction, nearest neighbor
in "j" direction, or bilinear.  
valid values: copy,spval,nn,nnoni,nnonj,bilinear
<br/>default: bilinear
</pre>
        </div>
    </td>
    <td>char*256(30)</td>
    <td>shr_strdata_nml</td>
  </tr>
  <tr id="mapmask_tr">
    <td><a name="mapmask"></a>
        <img id="mapmask_arrow" src="./images/arrow_right.gif">
        <code class="varname">
          <a href="javascript:void(0)"
