ANGULAR SURVEYING 



59 



It will be observed that both the latitude and the longitude 

 of A, as calculated from the preceding latitudes and longi- 

 tudes, should be zero. This is a check on the calculations. 



Having computed the latitudes and longitudes of the dif- 

 ferent corners, a plat of the field is very conveniently made as 

 follows: 



Draw a light pencil line SN, Fig. 3, to represent the reference 

 meridian, in such position that the plat will be as nearly in 

 the center of the sheet as can be estimated from an inspection of 

 the notes, or from a rough sketch previously made. On this 



meridian, mark the corner A from which latitudes and longi- 

 tudes are reckoned; that is, through which the reference 

 parallel of latitude is supposed to pass. From A, lay off on 

 SN distances ABi, ACi, etc., equal to the latitudes of B, C, etc., 

 upwards, if the latitudes are positive; downwards, if they are 

 negative. Through the points Bi, Ci, etc., draw light pencil 

 lines BiB', C\C', etc. perpendicular to SN, and on them lay off 

 distances BiB, CiC, etc. equal to the longitudes of the corners, 



