Subsurface Maps and Illustrations 



965 



be misconstrued should be fully explained in a legend. This applies also 

 to colors and colored lines which are not identified by notations where they 

 occur. The best location for the legend is near the title of the map. It 

 is bad drafting practice to place portions of the legend at several locations 

 in the margins. 



Using a name or a short explanation to identify a feature on the 

 body of the map is better than using a symbol which must be explained 

 in the legend. It is tiresome for the map reader to have to refer fre- 

 quently to a legend in order to understand the map. Explanatory notes 

 at the approximate location of the feature to which they refer can hardly 



Figure 520. Plat illustrating principles of township and range designations. 



be misconstrued and are less diverting than the see-saw reference to a 

 legend. 



(5) Geographic references — on a map which is well-planned and 

 correctly drafted, it is not difficult to describe the location of any feature 

 shown or to plot accurately new points of control. In other words, the 

 map base should contain all the reference lines necessary for these opera- 

 tions. In subsurface work it is annoying to work on a map whose base 

 consists of only geographic coordinates (meridians and parallels) . 



