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DigiCULT
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Info
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tions, the target group of the application
was identified as a group of `average, semi-
experienced computer user[s]'.Therefore
most of these users would have Microsoft
Windows OS driven computer systems
with Internet Explorer (installed as default
during the OS installation) and the `in
window' accelerated OpenGL graphics
support.The majority of Microsoft
Windows operating system users steered
the development process to the ActiveX
plug-in solution.
F
or the real time rendering of 3D
graphics Open-GL libraries are used.
Open-GL (http://www.opengl.org/) is a
well-established industry standard and is
supported by most operating systems and
graphics hardware developers.Thus, a large
portion of the code is platform independ-
ent and the rendering of 3D graphics is
hardware accelerated via the drivers of a
standard graphics card.
3
D ArchGIS retrieves the 3D object to
be explored from a remote server,
along with information from a database
where the latest measurements and scien-
tific data for each artefact are regularly
updated.The communication between the
server and the client is bi-directional (see
form independent but the fact that accel-
erated OpenGL graphics are not supported
by default raises the issue of the manual
download and installation of large files
(Java2 & Java 3D) by inexperienced users.
A
ctiveX plug-in is a well-established
method for developing software com-
ponents that can be executed within other
applications (modularity). It is supported
by a variety of software development plat-
forms such as
Microsoft Visual Basic,
Microsoft Visual C++,
and Delphi; however,
the main disadvantage
of this method is that
it is operating system
dependent (only avail-
able from Microsoft
Windows version95
and later) and browser
dependent (Internet
Explorer and Netscape
Navigator).
D
uring the initial
requirements
analysis and specifica-
a friendly graphical user interface (see
Figure 9). In this way, a laboratory which
conducts an extensive study on an archae-
ological artefact can provide the entirety of
the information regarding that artefact in a
very valuable and efficient way to scientists
all over the world.
TECHNOLOGY BEHIND 3D ARCHGIS
A
s mentioned earlier, the client com-
ponent of 3D ArchGIS is implement-
ed as a Web browser plug-in.The
advantage of running the application as a
plug-in within a single window is that it
allows the user to work in a consistent and
familiar environment without the need to
switch between separate application win-
dows. Furthermore, the versatile nature of
a plug-in software component permits the
application to be incorporated into bigger
Web projects and allows real multimedia
visualisation of the entire data set.This
very useful feature is, however, also a
restrictive factor that leads to some draw-
backs. As a browser plug-in, 3D ArchGIS is
restricted to Web oriented technology.The
most widely used technologies for devel-
opment in browser plug-ins are Java
applets and ActiveX. Java applets are plat-
3D
Arc
hGIS
,
2003
3D
Arc
hGIS
,
2003
Figure 8. Data from a point
Figure 9. Easy querying GUI