Reprinted from 
PHOTOGRAMMETRIC ENGINEERING 
April 
1956 
Hydrographic Application of Photogrammetry ın the 
United States Coast and Geodetic Survey” 
G. C. TEWINKEL, U. S. Coast and Geodetic Survey 
T publication of nautical charts of the coastline of the United States and 
its territories is one of the principal functions of the Coast and Geodetic 
Survey. The term “publication” here implies not only printing the charts, but 
also their construction and maintenance from the establishment of basic control 
surveys to the application of most recent changes. The problems encountered in 
providing this service differ somewhat from those of general topographic map- 
ping inasmuch as (1) the area is usually confined to a narrow, irregular strip 
along the coast, (2) the scale is relatively large, and (3) intensive detail is re- 
quired to serve an accurate and complete guide to the mariner. The advantages 
offered by photogrammetry are used to obtain basic topographic information 
and to aid the hydrographer. 
The Photogrammetry Division is one of the six operating divisions of the 
Coast and Geodetic Survey, the others being Coastal Surveys, Geodesy, Geo- 
physics, Tides and Currents, and Charts. Although the functions of the various 
divisions are fairly well denoted by their titles, it may be added that the 
Coastal Surveys Division operates the hydrographic vessels and performs the 
hydrographic surveys; the Photogrammetry Division provides, through the use 
of aerial photography, the topographic and control information required to 
locate inshore hydrography and to compile and maintain the nautical charts; 
and the Charts Division compiles, engraves, prints, and distributes the charts. 
The Photogrammetry Division, in turn, utilizes data provided by the Geodesy 
Division and the Tides and Currents Division, and supplements such data with 
observations of its own whenever it is advantageous. 
The Photogrammetry Division comprises an unusually complete organiza- 
tional unit. It owns its aerial cameras and the navigator and photographer are 
members of the Division. It processes its own film and reproduces its prints, 
enlargements and diapositives. The Division operates its own mobile field 
parties and compilation offices. It has a series of stereoscopic plotting instru- 
ments for nearly every appropriate application. A drafting unit is included for 
finishing and scribing the completed manuscripts. A small research group stud- 
ies new techniques and strives to improve the old ones. The different phases of 
the work are united through an Operations Branch. By this complete organi- 
zation, the Division is able to control and coordinate its activities including 
flicht planning, aerial photography, control surveys, compilation, drafting, etc. 
The photographic airplane is provided by another bureau, the U. S. Coast 
Guard, which cooperates completely in supplying the service when and where 
it is required. Additional airplane service is obtained through private firms by 
a contract arrangement whereby the Division's navigator-pilot and photog- 
rapher operate the equipment. 
* This paper is a contribution to Commission IV of the International Society of Photogram- 
metry. 
U.S.A—1