BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 30, pp. 405-414 September 3o, i919 



MILITAEY AND GEOLOGIC MAPPING— A PLAKE-TABLE ^ 



BY ALAI^ M. BATEMAN" 



{Presented by title before the Society December 28, 1918) 



CONTENTS 



Page 



Introduction 405 



Equipment 406 



Cost 406 



Plane-table 406 



Alidade 407 



Compass 408 



Slope card 408 



Scales 410 



Methods 411 



Construction and use of slope scale 411 



Conclusions 413 



In^troduction 



In most branches of the army a knowledge of map reading and mapping 

 methods is necessary, and in the artillery it is essential. ISTot only must 

 the artillery officer be conversant with the interpretation of maps, mili- 

 tary and topographic, but he must have knowledge and skill in making 

 sketches and in locating positions by traverses, intersection, and resection. 



Much of this work is of a reconnaissance nature, with a considerable 

 allowable error, but where it involves the locating of batteries and battery 

 commander stations for use upon firing* maps, the locations must be 

 accurately made. These locations are preferably made by intersection, 

 simple resection, or by Italian resection^ or other three-point methods 

 which give a high degree of accuracy. For all such purposes the plane- 



1 Manuscript received by the Secretary of tlie Society February 7, 1919. 



2 Italian resection is one of the three-point methods of accurately locating a position 

 and orientating a map when three points on the map can be seen on the ground. It 

 was adapted by the Italian Army from Bassell's method ; hence its name. It was later 

 adopted by the French and American armies as the authorized method for locating posi- 

 tions where accuracy is required. 



(405) 



