40
Number 43, Fall 2002
cartographic perspectives
Figure 19. Two rows of vector-based point symbols centered in square grid cells. Symbols in the second row have been rotated 45° clockwise around the
center of the grid cells. Overlap of the black point symbols in the second row results in a decrease in overall darkness between rows from 28% gray to 22%
gray, a relative change of more than 20%.
Figure 18. The same hillshaded map in Figure 15 dithered with the halftone patterns from Figure 10
oriented perpendicular to the aspect direction.
