Volcano

## =======================================================================
## Image with contour specification (alpha sets the transparency)
## implemented by Karline Soetaert
## =======================================================================

require(plot3D)
image2D(volcano, shade = 0.2, rasterImage = TRUE, main = "volcano",
    contour = list(col = "white", labcex = 0.8, lwd = 3, alpha = 0.5),
    colkey = list(length = 0.5, width = 0.5)  )