>> 
>> 
>> 
>> 
>> load InterpEx
>> whos
  Name      Size                   Bytes  Class

  X        20x20                    3200  double array
  Y        20x20                    3200  double array
  Z        20x20                    3200  double array
  hex       7x6                      336  double array
  x         1x20                     160  double array
  xy       24x2                      384  double array
  y        20x1                      160  double array

Grand total is 1330 elements using 10640 bytes

>> pcolor(x,y,Z);
>> shading('interp');hold on
>> h=polygonmesh(hex, xy);
>> Zh=interp2(x, y, Z, xy(:,1),xy(:,2));
>> clf
>> pcolor(x,y,Z);hold on
>> shading('interp');hold on
>> h=polygonsurf(hex, xy, Zh);
>> Zl=griddata(xy(:,1),xy(:,2),Zh, X, Y);
>> clf
>> surf(x,y,Zl);shading('interp')
>> clf
>> h=surf(x,y,Z);hold on
>> set(h,'facecolor','interp')
>> set(h,'Cdata',Zl-Z)
>> colorbar
>> diary off