Protovis - A graphical approach to visualization

Protovis composes custom views of data with simple marks such as bars and dots. Unlike low-level graphics libraries that quickly become tedious for visualization, Protovis defines marks through dynamic properties that encode data, allowing inheritance, scales and layouts to simplify construction. Protovis is a graphical toolkit, designed for visualization. It retains some of the conceptual simplicity and low-level control of graphical systems by dealing directly with graphical elements.