419 
OBSERVATIONS AND TRENDS 
in 
DIGITAL CARTOGRAPHY 
1982 
Robert B. McEwen 
U.S. Geological Survey 
Reston, Virginia 22092 
ABSTRACT 
The USGS National Mapping Division is undergoing a major transition from 
analog to digital cartography that will be more profound than the tran 
sition from planetable methods to photogrammetry 40 years ago. This 
transition is taking place against a framework of inexorable trends in 
mapping, automated data processing, and digital cartography itself that 
strongly influence the course and rate of developments. Mapping costs 
increase, resources decrease, revision requirements increase, and custom 
map requirements increase. ADP equipment and storage costs decrease, 
software costs increase, and Very Large System Integration (VLSI) capa 
bilities soar. Meanwhile, map digitizing costs are still high, data 
base coverage has not achieved a critical mass, and automated carto 
graphic and geographic information system applications are maturing so 
very slowly. Charting a course through these trends and conditions will 
be a major accomplishment for a large mapping organization. 
INTRODUCTION 
The National Mapping Division (NMD) of the U.S. Geological Survey is 
actively adopting computer technologies to support its mission of 
collecting cartographic data at a national level for the United States. 
Early, it was recognized that traditional cartographic methods would 
some day be replaced by predominantly digital techniques, and the 
concept of a national digital cartographic data base was formulated 
during the mid-1970's. The desirability of such a data base was gen 
erally accepted, but the process of turning a general concept into 
reality was recognized as being fraught with both technical and pro 
cedural difficulties. 
The status of digital cartography in the NMD has been previously 
described (McEwen and Calkins, 1981) and will be briefly summarized 
here. In addition, the diagrams in this paper are intended to illustrate 
observations and trends that are important in gaining an overall 
perspective for planning the transition from analog cartography to 
digital cartography in a large national mapping agency. 
The terms "analog" and "digital" cartography are being used for several 
reasons. The current analog cartographic process is not without certain 
digital phases such as analytical photogrammetry, geodetic computations, 
and the automated computation and plotting of base projections. However, 
The use of trade names and trademarks in this publication is for des 
criptive purposes only and does not constitute endorsement by the U.S. 
Geological Survey. 
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