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REPRESENTING TOPOLOGIC PROPERTIES IN RASTER DATA STRUCTURES 
J. R. Muller and R. P. O'Connor 
Synectics Corporation 
310 E. Chestnut Street 
Rome, NY 13440 
BIOGRAPHICAL SKETCH 
James R. Muller received an M.S. degree in Urban Planning from the 
University of Washington, Seattle, WA in 1979 and a B.S. in Geography 
from the State University of New York, Oneonta, NY in 1975. He is 
currently serving as project director of the Interactive Raster Data 
Structures (IRDS) study sponsored by the Rome Air Development Center 
(RADC). Previous experience includes automated cartography, remote 
sensing, and geographic information systems. 
R. Patrick O'Connor is a graduate of Syracuse University with a B.S. 
degree in Mathematics. He is currently serving as principal investi- 
gator of the IRDS study. Mr O'Connor has been involved in automated 
cartography and interactive systems since 1972. Additional experience 
includes systems programming and implementation of real-time radar 
and data acquisition systems. 
ABSTRACT 
A major obstacle to satisfying the need for digital cartographic data 
has been the high cost and long lead time associated with data capture 
of cartographic source material. Dramatic improvements in the rate of 
data capture and in the processing of cartographic data are promised 
by the emergence of raster technology within the digital mapping arena. 
A major deterrent to the acceptance of raster data has been the in 
ability to interact with cartographic entities as features and 
segments. This interaction can be improved by a raster data structure 
which expresses basic topologic properties. This paper defines the 
topologic properties of raster data, presents an encoding scheme for 
representing neighborhood connectivity, and examines techniques for 
interpreting other properties from the data. Finally, an example 
illustrates the enhancement of cartographic editing through this 
procedure. 
INTRODUCTION 
Synectics Corporation is currently performing a research and develop 
ment effort for the Rome Air Development Center (RADC) entitled 
"Interactive Raster Data Structures (IRDS)". The purpose of this 
study is to survey and investigate data structures and techniques