CHAPTER V 



Subject 

 com- 

 prised in 

 Chapter. 



Great 

 Care 

 requisite 

 in Plot- 

 ting. 



PLOTTING 



This chapter will comprise, besides a description of the method 

 of placing the points on the paper, which is more generally 

 understood by the term " plotting," an account of the different 

 manners in which those points may be obtained, other than by 

 a regular chain of triangles. This is, perhaps, more correctly 

 a part of triangulation, and for some reasons should be described 

 under that article, but it is thought that it will tend to clear- 

 ness of comprehension, if it is taken in connection with the 

 mode of laying do^^^l the points as obtained, as it is not easy 

 to separate the two steps in many instances. 



In discussing the general question of Plotting, therefore, 

 we vnll first take the placing of the points of an ordinary 

 triangulated survey on paper, and then consider some 

 other systems to be adopted when regular triangulation 

 fails us. 



Plotting the points is a most important operation, and one 

 requiring great care. 



No matter on what scale or on what system a survey is 

 being made, equal pains must be bestowed on plotting the 

 points. Indeed, it may almost be said that in proportion as 

 the elements of a survey approach to the least accurate form, 

 viz., a sketch survey, so does the necessity for careful plotting 

 increase, as the numerous checks, which in a detailed triangula- 

 tion will instantly make any error in plotting apparent, Avill 

 be more or less absent in proportion to the departure from 

 such regular triangulation ; and not only will the minor details 

 of such a chart be inaccurate, wliich we expect, but the main 

 and prominent points may be unnecessarily out of place unless 

 care is bestowed on the plotting. 



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