International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
multiple scenarios at the same time, below shown a 3D model
fly through with a LIDAR image and single vector layer of the
airport airfield obstructions, this reflects the capability of
visualizing a single 3D layer based on the Digital Elevation
Model (DEM) and as well as multiple layers. 3D fly through
control panel in GeoServNet 3D model allows for controling
the fly elevation, fly pitch and speed. These model controls are
very effective in allowing for different controls and angles.
Figure 5 - 3D fly-through model showing the change in layers
of the Airport model
3.4 Significance of 3D modeling for Emergency
Preparedness:
The answer to the question: what is special about 3D GIS?
Depends on the interpreter's point of view most of the time, if
3D GIS are compared to 2D GIS, simply, there is one major
difference which is the amount of data to be processed. Since
the amounts of data to be used for 3D visualization are far more
than 2D including the DEM and other 3D visualization aspects.
The advantage of 3D visualization mainly based on the way we
visualize the data and how we may interpret and perceive the
fact of what we have modeled, whether it is symbolic
conceptual or semi real world as in 3D perspective display.
The main utility for web-based visualization. systems for
disaster managers is based on four criteria: (1) what type of
information is needed (2) when this information is used, (3)
where this information is acquired and stored, (4) how
information is delivered during emergencies, and at what pace
it is needed. By applying these four criteria on all the
information used during emergency response, particular
information is classified and analysed. The results of this
analysis might be considered as the base for the investigation of
the possible ways to transfer information (How?), besides
ordinary one to one communication. The advantage of
visualization of critical infrastructure models through the
internet is crucial, since it provides different decision making
levels with near real-time data access, which would
significantly expedite the processes of evaluating and
analyzing information and taking decisions based on the model
generated from Santa Barbara Airport.
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Besides the ease that GIS data visualization brings, still there
are some issues that are arising from data visualization, which
may cause uncertainty. These issues include data quality and
format, the representation and modeling the real world,
interpreter's objectives in interpretation objectives as well as
visualizations objectives. Another important factor is the
abilities and targets of the analyst who will be using the model.
Data Characteristics include, data reljability, accuracy and
interpretation aims, which are defined by the viewer for
identifying objects, and comparing values, distinguishing
objects, categorizing objects, this include software capabilities,
and whether the focus on text/data
structures/performance/algorithm in addition to what type of
information visualization is required and whether the focus is
on detail or the over all view, or relations among other objects.
User's desires and abilities which are restricted by color
perception ability and color coding, and preferences in addition
to the availability of the suitable software, including
visualization capabilities. Real time connections in some cases
(field data collection) and color coding and information
communication to the public may be considered as other
limitation to visualization of similar models.
4. CONCLUSIONS
Responding to unexpected disasters, whether natural or man-
made, is one of the greatest technological challenges ever to
face. Events fall completely outside the range of the planned
capabilities of organizational tasks. Moreover, major
components, entirely unplanned, need to interoperate and
policies and technologies need to converge in real-time. The
scope of research and development (R&D) in responding to the
unexpected (RUE) requires a broad range of technologies and
relationships, among those is certainly, 3D web-based GIS.
Research in responding to unexpected events engages issues
ranging from risk assessment of major assets (human,
structural, transactional, etc) to scenario building and
organizational decision systems and architecture. A major focus
of the research agenda is the application of information
technology tools and systems. The scope of Disaster
Management, Infrastructure Protection and Emergency
Response research is beyond the capabilities of even modest-
sized research teams, this mainly: because the need for
interdisciplinary vast research group.
Visualization Technologies are developing the same as web-
based GIS, so the interaction level would be high in the near
future, and the needs would be more. Therefore, critical
Infrastructure protection using 3D web-based GIS is evolving.
In Canada, the Office of Critical Infrastructure Protection and
Emergency Preparedness (OCIPEP) was founded in 2001 with
growing applications and needs for web-based GIS. This would
certainly support the growing demand for Web-based GIS. GIS
is gaining more grounds and is unique for such applications.
Two central issues are very crucial in 3D web-based GIS
applications for Infrastructure Protection and Emergency
Preparedness, they are the need of strategic plans that minimize
data flow and emergency planning that GIS would contribute
considerably. Findings of this research have clearly
demonstrated that the application of web-based GIS for disaster
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