Barry,

I don't think you can reach that conclusion on the basis of that map. There may several plausible explanation for the features on Mars that appear to be created by water.

Indeed, I think its very reasonable to think that water has shaped many of these ancient features. But I don't that requires that Mars once sported oceans and lakes. Moreover, it appears that the presence of large volumes of liquid water on the surface of Mars would have been short-lived. I think the evidence is leading to the conclusion that Mars has pretty much been freeze-dried for most of its existence, punctuated by brief and catastrophic episodes where liquid water shaped the surface. We shall see if this idea holds up over time as more data is assembled.

Donald