function Myplot(x,y,z,a)   

[matxpix,matypix]=meshgrid(linspace(min(x),max(x),512),linspace(min(y),max(y),512)); %Centre de Gravité             
matzpix=griddata(x,y,z,matxpix,matypix);
matapix=griddata(x,y,a,matxpix,matypix);
figure; surf(matxpix,matypix,matzpix,matapix,'line','none');colorbar;axis equal;view(3)