Abstract: A system and method for fast efficient contour shading of spatially sampled data presents accurate contour regions. The system and method render a contour graphic for display by obtaining a set of gridded data, dividing the set of gridded data into tiles, analyzing each tile sequentially to determine contour levels within each tile from lowest contour level to highest contour level, creating a contour region based upon the determined contour levels, drawing contour lines based upon the determined contour levels, shading the contour regions, and providing the shaded contoured region for display. The system and method make a single pass through the gridded data rather than exhaustively detecting contour levels of interest and following the detected levels of interest through the grid of data using analytic and interpolative approaches.