An Ecological Assessment of the Louisiana Tensas River Basin Chapter 1 
El 
i— 
Figure 1.8 illustrates one method of measuring a land¬ 
scape indicator. This method ("overlaying") simply 
overlays maps of different themes in order to extract 
information about spatial relationships among the 
themes. These relationships are then stored as a new 
map which combines the information from the original set 
of maps. 
Figure 1.8 
Land cover (with agriculture in red) is combined with topography to indicate 
agriculture on steep slopes. The combined map shows agriculture on slopes 
greater than 3%. 
