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THE POTENTIAL OF HYPERMEDIA TO PHOTOINTERPRETATION 
EDUCATION AND TRAINING 
D.P. Argialas O.W. Mintzer 
Remote Sensing Laboratory U.S. Army TEC. 
Dept. of Surveying Engineering ATTN: CEETL-RI-T 
National Technical University 2592 Leaf Road 
9 Heroon Polytechniou Str. Fort Belvoir, VA 22060-5546 
Zografos 15773, Greece USA 
Commission VI 
PURPOSE: 
Hypermedia is an authoring environment, an idea organizer tool or a conceptual indexing tool. A 
hypermedia information base consists of interlinked pieces of text, graphics, full motion video, 
animation and sound. The authors examine how educators teaching photointerpretation could use 
this technology for more effective presentation and teaching. A photointerpretation hypermedia 
system can help put information related to objects, attributes, their clues and recognition methods 
in obvious patterns so students could interactively and non-sequentially locate, browse, and 
understand the photointerpretation concepts and processes. The marriage of multimedia and expert 
systems is also inevitable. Hypermedia systems can help to build less ambiguous decision 
support systems and knowledge-bases and thus make expert interpretation systems more intuitive. 
KEY WORDS: 
hypercard, teaching 
INTRODUCTION 
Photointerpretation is still an art, using 
science for only its most basic foundations. 
Practice relies on the case-study method and 
intuitive judgement more heavily than is 
commonly believed. Photointerpretation 
relies on an imprecise combination of 
information gathered in different ways and 
processed in a largely intuitive and recursive 
fashion. Overall impressions are gathered 
and interpretations are made, but the 
photointerpretation process remains obscure 
(Argialas et al, 1999). "There are few 
definitions and descriptions of 
photointerpretation objects given in the 
literature. And, there are even fewer 
explanations of the procedural or inferential 
framework of the interpretation process 
(Argialas and Narasimhan, 1988a; 
Narasimhan and Argialas, 1989). This may 
be so because of the difficulty of the problem 
itself, the lack of theory and technology to 
assist in the symbolic representation of the 
complex inferential process (Argialas and 
Narasimhan 1988b), and in the extraordinary 
emphasis that has been placed on the digital 
image processing paradigm. The last reason 
has contributed to our sidetracking from 
forming a workable photointerpretation 
paradigm (Ryerson, 1989). For the last two 
decades little attention has been paid to 
rigorous, visually-based image interpretation. 
This severely reduces our ability to 
effectively interpret and use the TM, SPOT, 
and other sensor images. 
There is, therefore, a need to study 
methodically the process of building 
photointerpretation keys and to develop a 
systematic framework for the recognition of 
objects from aerial images using information 
specific to how objects appear on a given 
image as well as information available in the 
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Photointerpretation, hypermedia, expert systems, knowledge representation 
mental models of expert photointerpreters. 
The proper application of such keys will 
allow a novice interpreter to tap onto the 
knowledge base of the individual who 
offered her/his knowledge for building the 
key. To build such keys it is necessary to 
have a thorough understanding of the domain 
specific knowledge and of the new theories 
and technologies in representing, managing, 
retrieving and formalizing knowledge 
(Nielsen, 1990; Shneiderman and Kearsley, 
1989; Parsaye et al, 1989;Bielawski and 
Lewand, 1990). Advances in hardware and 
software has contributed to a new set of 
techniques for computer aided instruction and 
presentation systems of unparalleled impact. 
Hypermedia and knowledge-based expert 
systems can offer us the base on which to 
develop a workable visual image 
interpretation paradigm similar to the keys of 
the past. Argialas and Harlow (1990) have 
examined the potential of expert systems for 
image interpretation. In this paper the authors 
examine the potential of hypermedia for 
photointerpretation and present the rationale 
underlying the structure and design of such 
systems. 
THE HYPERMEDIA CONCEPT 
Hypertext was born of the need to devise text 
storage and retrieval systems capable of 
managing efficient large masses of 
information. All traditional text, whether in 
printed form or computer files, is sequential, 
that is there is a single linear sequence 
defining the order in which the text is read. 
The idea behind hypertext is to read text non- 
sequentially. Hypertext has departed from 
the sequential, linear storage and retrieval of 
text to a random-access, nonlinear method 
with many options and alternatives (nielsen, 
1990). Hypertext can present several options 
to its readers, and each one determines which