Here a computer program has been written to 
obtain a Digital Terrain Model which is a regularly 
spaced grid of height points discrete from ir- 
regularly spaced points such as digitized con- 
tours. 
Authors: Dr. K. Kubik (Netherlands) 
Dr. A. Botman (Netherlands) 
Title: Interpolation Accuracy for Topo- 
graphic and Geological Surfaces 
PP III/32 
This paper considers the theoretical accuracy 
of point interpolation for topographic and geo- 
logical surfaces. The accuracy results prove that 
interpolation accuracy depends primarily on the 
properties of the surface, on the spacing of the 
control points, and, to a much lesser extent, on 
the interpolation methods used. 
Author: Dr. W. Marckwardt (G.D.R.) 
Title: The Mathematical Treatment of Digi- 
tized Curved Lines PP ///30 
A qualitative characteristic is correlated to each 
digitized point, permitting an analysis of the 
curve with a view to generalization and decima- 
tion of the data set to be stored. 
Author: Dr. U. Rauhala (U.S.A.) 
Title: A Review of Array Algebra PP 111/48 
Array algebra is a concept generalizing conven- 
tional vector, matrix and tensor algebra. It deals 
with systems of multilinear equations that are at 
the base of the "fast" solution algorithms like 
the FFT. Estimation using array algebra is based 
on the theory of loop inverses, which is an ex- 
tension of the generalized matrix inverses. A 
multilinear function theory, the array prediction 
using covariance functions, is the main applica- 
tion of the array estimation. It is based on banded 
R-matrices. With a regular grid of data consider- 
able savings are achieved in computation and 
core space requirements compared with the 
conventional case. 
The first paper of the session was presented by 
Mr. G. Schut from Canada. 
Invited Paper 
Author: Mr. G. Schut (Canada) 
Title: Interpolation Methods for Digital 
Terrain Models IP 111/07 
This paper reviewed the methods of height inter- 
polation for digital terrain models which had 
been published in photogrammetric and related 
journals. 
In the course of the following general discus- 
sion, Dr. U. Rauhala (U.S.A.) said that his array 
algebra provides a general solution for all inter- 
polation methods. He said an advantage of his 
method is that the computer time required in- 
creases only linearly with the number of pa- 
rameters used. 
Presented Papers 
Author: Mr. O. Ayeni (U.S.A.) 
Title: Objective Terrain Description and 
Classification for Digital Terrain 
Models PP 11/71 
Here various quantitative methods for describing 
102 
a terrain had been investigated. Based on the 
different terrain characteristics four major classes 
of terrains which span the whole spectrum of 
terrain types had been identified, using tech- 
niques of objective classification theory derived 
from multivariate statistical cluster analysis. 
Suggestions were made as to how the reactions 
of various interpolation techniques could be 
properly evaluated in relation to the four major 
classes of terrains with a view to achieving auto- 
mation. 
Author: Dr. W. Stanger (F.R.G.) 
Title: The Stuttgart Contour Program 
SCOP — Further Development and 
Review of Its Application PP ////56 
The Stuttgart Contour Program SCOP described 
here has been conceived as an independent part 
of a data flow ranging from (semi) automatic 
data acquisition up to the automatic plotting 
of isolines. A grid-form digital terrain model is 
obtained as an intermediate result. This D.T.M. 
also provides a wealth of information and has 
many independent uses. The possibility of using 
the SCOP program for the production of special- 
purpose thematic maps also deserves mention. 
Author: Mr. E. Assmus (Austria) 
Title: Extension of Stuttgart Contour Pro- 
gram to Treating Terrain Break-Lines 
— Theory and Results PP 111/10 
For the computation of maps with complex geo- 
morphological structures an expanded program 
version SCOP-B has been developed. For this 
purpose linear prediction has been modified in 
such a way as not to permit the points separated 
by terrain break-lines to correlate with one an- 
other. In this way the edges of the terrain are 
clearly indicated. This paper deals with the 
theoretical foundations of program extension and 
its technical realisation. With the aid of a number 
of maps, computed by means of SCOP-B, the 
absolute accuracy of the contour lines is ex- 
amined and their cartographic quality demon- 
strated. 
Author: Dr. O. Hofmann (F.R.G.) 
Title: KARTOSCAN — A New MBB-Data- 
Acquisition System for Cartography 
Use PP 1l/19 
KARTOSCAN is a fully automatic system for the 
digitization of maps, especially contour lines. 
Compared with conventional digitization methods, 
the time-consumption is 1/500. A computer is 
used for the formation of lines from the tonal 
values of all screen points stored on magnetic 
tape. 
Authors: Mr. A. Beier (G.D.R.) 
Mr. P. Hanke (G.D.R.) 
Title: The DIGICART Data Processing Sys- 
tem and Its Applicability to Survey- 
ing and Mapping PP 11/13 
The introduction of electronic data processing 
to surveying was exemplified by the DIGICART 
project. The capabilities and automatic facilities 
of the system were explained, covering the 
processes from aerial photography to the pro- 
duction of the topographical map. DIGICART 
permits the selective acquisition, processing and