Thanks Sigurd. I created the map witrh an older version of Photoshop (6.0 or 7.0 - I can't remember which). As for the ripple effect, it is just that. It is a Filter called Ripple (Filter --> Distort --> Ripple). There are three choices for the type of ripples: small, medium and large. There is also a sliding scale that determines how strong these ripples are rendered. I often use medium ripples with a value between 60 to 100%. It depends on what look I'm going for. For caverns I might use large ripples with a value of over 100% (or below -100%).