Case study: visualizing ocean currents with color and dithering

This case study presents several related approaches to visualizing flow information from large vector volumes generated by ocean circulation modeling. Flow vectors are mapped to colored pixels to enable global views of dense three-dimensional vector fields. Each of the approaches starts by classifying vector direction into a small number of colors. One approach then uses scaled linear interpolation to blend between adjacent directional colors. Two other approaches use half-toning and dithering methods to rapidly display flow information. By using opponent colors for our directional encoding, we can blend colors, either through linear interpolation or the user's visual system, into intermediate colors without expressly calculating them by a conversion to polar coordinates.