Character vector for color specification, either "BlueWhiteRed", "GreenWhiteRed", "GreenYellowRed","GreenBlackRed", "YellowToRed", or "BlackOnly". Default is "BlueWhiteRed".
scale.location
Non negative integer representing color scale location, 1~4 for
bottom, left, top, and right.
scale.width
Non-negative numeric, width of color scale. if not defined, 1/2 of x axis will be used
scale.height
Non-negative numeric, height of color scale. if not defined, 1/10 of scaleWidth axis will be used