John Park and the Digital Arts program at the University of Oregon present a 40 minute video of visualizing data in Processing. The technique covers loading data into arrays, accessing that data in FOR LOOPs and transforming visualized elements using rotate() and pushMatrix()/popMatrix().
This is an intermediate to advanced tutorial.
More information about Digital Arts at the University of Oregon: http://darts.uoregon.edu
Download the Processing Sketch: http://pages.uoregon.edu/park/transfer/RadialDataViz.zip