- 1745 - 
Pennsylvania/Williams and Stauffer 
  
  
(c) MSS-7 LANDSAT difference of 1976 to 1977 
FIGURE 5.2. GEOMETRICALLY REGISTERED LANDSAT SUB-IMAGES SUBTRACTED TO YIELD 
A DIFFERENCE IMAGE WHICH HIGHLIGHTS AREAS OF CHANGE. Note the dark gray tone along 
the ridge line in the upper right corner and center of the difference image (c). This dark tone represents 
forested areas with intact foliage in 1976 (a) and severely depleted foliage in 1977 (b) due to heavy feed- i 
ing by gypsy moth caterpillars. | 
l'O YIELD | 
y tone along 
e represents 
» heavy feed-