Training (Barnicot, 1994) are often used. In this paper the term
CAL has been adopted.
The Laboratory of Photogrammetry of the National Technical
University of Athens (NTUA), teaches Photogrammetry to
classes of approximately 120 students of the 3rd and 4th years
of the Department of Rural and Surveying Engineering. It
occurs so that some of the basic functional problems of NTUA
such as the large amount of students, or the insufficient
instrumentation should be confronted with the introduction of
new technological means for learning, educating, exercising
and training the students with the help of computers.
The application developed is a multimedia educational program,
whose target is to provide the student with the opportunity to
assimilate basic photogrammetric theories and comprehend
the various application fields. The presentation of geometrical
concepts in modern audio-visual ways is mainly attempted,
whereas at the same time it demands the active participation
of the user through interaction and obligatory exercises. The
application has been designed for self-studying and self
exercising by the student and has been named
"Photogrammetrist v.1.0". A later modification of the existing
program is expected to expand the potentiality of the system
in researching or as a multimedia aid in classroom teaching.
2. MULTIMEDIA AND AUTHORING SOFTWARE
Computers alone cannot cause enthusiasm nor can they
emphasise concepts. The messages should be transmitted in
a way that causes and captures the user's attention, satisfying
and stimulating his senses without misleading him. The
concepts should be presented clearly, precisely and
comprehensively. The power of information does not relate to
the data but to the ideas, the senses and the actions of people
who come into contact with it. The transmission of information
can be executed efficiently, when it complies with four basic
rules (Lindstrom, 1994):
a. It should capture the attention of the audience.
b. The messages should be precise and clear so that
comprehension may be easily achieved.
Cc. The agreement of the audience with the messages
must be absolute (scepticism can destroy the
sequence).
d. The assimilation of messages by the user when
combined with comprehension leads to knowledge.
Modern computing provides the capability of multisensory
communication, a characteristic of which multimedia
technology takes advantage. Operating systems have since
several years adopted the Graphical User Interface (GUI)
based on the of Windows-lcons-Menu-Pointer (WIMP)
environment. Thus it was possible to develop interactive
teaching programs. The communication between the
computer-teacher and the student does not take place within
a certain order of questions and answers, or like a monologue.
The interaction helps the user focus on the desired theme,
while the computer can answer his questions instantly.
Furthermore, navigation can be done by the user at his own
learning speed, while cross-references between different
topics are possible. Interaction has a significant role in
education: Learning by acting is an old and proven principle in
education.
Multimedia applications are usually developed with the help of
a suitable authoring software, which provides the necessary
tools for integrating text, images, video, sound and animation.
Multimedia provide communication with the user in many ways.
Written text is only the 8% of communication. Sound and
speech are the 36%, while the visual communication (graphics,
images etc.) occupies the remaining 56%. Yet the integration
of communication can only then be achieved, if it is close to
human senses, i.e. to the natural way students interact.
Interaction gives the ability to access information at the time
and way the user desires. The great advantage of multimedia
is that they combine the above mentioned features in a digital
form, thus permitting their simultaneous use and direct access
to information, provided by dynamic images with changes in
shape, size, colour, use of sound, animation and video.
On the other hand, in hypertext applications information is
related to appropriate text and can equally easily be studied.
A multimedia system (text, graphics, images, animation,
sound, video) is not necessarily Hypermedia. Only when the
user, by interacting with the system, takes control of a set of
dynamic links, the system can be characterised as
Hypermedia. The contribution of hypermedia to the teaching
and learning process, is that it offers the means to organise
"knowledge" in a way, it can easily and effectively be
accessed. The author offers to the user the opportunity to
navigate through a certain subject, by dividing information into
modules and determining a set of nodes and links between
them (Argialas 1992). Hypermedia is ideal for non-linear
programs and random knowledge searching (Figure 1).
Although hypermedia permits browsing through a vast amount
of information, it is not the solution to efficient learning. The
user can easily be misled and lost in a labyrinth of information.
Freedom in accessing information has a price and the user can
be lost in hyperspace. In a training, self-studying application,
on the contrary, the interests that the program stimulates must
be, in a way, unique.
USER
INTERFACE
46
| i ;
Y Y
BROWSING SEARCHING. À—— — —
| ACCESSIBILITY
bem — AND
| VISUALISATION
Figure 1: Structure of Hypertext non-linear browsing
As already mentioned, on the opposite side of Hypermedia
stands Computer Based Training (CBT). A CBT application is
structured in distinct educational units (Figure 2). Each unit
consists of subunits which can be displayed as progressive
steps of successive ideas with an increasing degree of
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996
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