plot2D figure.
addLegend(object, fcol = "markers", where = c("other", "bottomright", "bottom", "bottomleft", "left", "topleft", "top", "topright", "right", "center"), col, bty = "n", ...)MSnSetmarkers."other", "bottomleft",
"bottomright", "topleft" or "topright" defining
the location of the legend. "other" opens a new graphics device,
while the other locations are passed to legend.character defining point colours.legend. Default is set to
"n".legend.NULL
plot2D for details.