Geoscience Reference
In-Depth Information
1 Introduction
Designing 3D navigation systems requires addressing solution methods for
complex topologies, 3D modelling, visualization, topological network analysis
and so on. The most important issue for realizing these solutions is gathering accu-
rate 3D spatial data and for GIS researchers data collection is still one of the most
challenging procedure.
Data generation is also still a problem for the researchers who work on GIS
based 3D navigation systems which consumes their time more than doing their
research. Gathering vectorized data from archives may reduce time and cost for
GIS projects but these vectorized data can not be used in a GIS without the geomet-
rical and topological corrections and needs post processing. Following a vectoriza-
tion process the geometrical and topological corrections for the intersection points
of the lines should have been performed which are very important to efficiently use
the extracted vector data in GIS and other spatial applications. Second section of
this study addresses efficient data generation process for a 3D network model.
3D navigation within 3D-GIS environment is increasingly growing and spread-
ing to various fields. One of those fields is evacuation through the shortest path
with safety in case of disasters such as fire, massive terrorist attacks happening
in complex and tall buildings of today's world. Especially fire with no doubt is
one of the most dangerous disaster threatening the high rise and complex buildings
including thousands of occupants inside.
In research environments, two main approaches to indoor evacuation systems are
currently accepted. One is 3D modeling environment that this study follows and the
other is fire simulation models. Originating from 3D modeling environment, evacu-
ation and routing is based on graph networks (Karas et al.
2006
; Jun et al.
2009
),
while 3D visualization problems achieved by CityGML (Kolbe
2008
) and most
studies used to work with Lee's Node Relation Structure on 3D network construc-
tion (Lee
2001
). Disasters such as world trade center 9/11 have made researchers
attempt to use GIS technologies in response to disasters occurring in microspace of
multilevel structures such as interior of the buildings in urban areas (Lee
2007
).
Kwan and Lee (
2005
) examined the potential of using real-time 3D GIS for
the development and implementation of GIS-based intelligent emergency response
systems (GIERS) that aim at facilitating quick emergency response to terrorist
attacks on multi-level structures. They observed that extending conventional 2D
GIS to 3D GIS representations of the internal structures of high-rise buildings can
significantly improve the overall speed of rescue operations. Their findings have
motivated other geospatial scientists to develop intelligent emergency evacuation
systems for complex buildings using 3D GIS (Meijers et al.
2005
).
Network modelling based evacuation approaches have concentrated on modifi-
cation of Dijkstra's shortest path algorithm with distance or time as edge weights.
Evacuation of a building in case of emergency requires the evaluation of various
human and environmental factors such as distribution of people inside the building,
avoided exits, interactions of people with each other, their physical features, behavior
