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USES OF HIGH-RESOLUTION IMAGERY FOR URBAN TRANSPORTATION
APPLICATIONS: QUANTITATIVE INDICES EXTRACTION APPROACHES
K.Lee?, K.- H. Chi?
“Dept. of Information Systems, Hansung University, Seoul, 136-792, KOREA - kilec@hansung.ac kr
? KIGAM( Korea Institute of Geoscience and Mineral Resources), Daejeon-city, 305-350, KOREA
- khchi@rock25t.kigam.re.kr
KEY WORDS: Extraction, High resolution, GIS, Indicators, Urban
ABSTRACT:
Recently, new approaches with commercial high-resolution satellite imagery in the engineering application domains have been
attempted. Among them, uses of remotely sensed imagery linked with GIS-T (Geographic Information Systems for Transportation)
or transportation geography are regarded as one of prospecting issues. As the matter of facts. most transportation applications are
needed real-time or near real-time processing for data acquisition, analysis, or broadcasting; comparatively, uses of remotely sensed
imagery in this field are somewhat oriented to periodic change detection and analysis, prediction and forecasting. Even in this
approach, high-resolution imagery is more advantageous than coarse and medium resolution imagery. Normally, two kinds of
approaches are prevailed such as image recognition/interpretation and automatic or semi-automatic feature extraction. With this base
considerations and engineering viewpoints, practical uses of remote sensed imagery in urban transportation environment analyses
were carried out with newly implemented extension programs running under desktop GIS environment in this study: Connectivity
index and Circuity index, which mean degree of connectivity and degree of circuit in a network, respectively. As for connectivity
index, three types of algorithms such as alpha, gamma, and shimbel index were implemented, and extraction program of circuity and
accessibility matrix were implemented with OD (Origin-Destination) matrix computation used in travel demand analysis in
transportation geography. In both cases, high-resolution imagery is used in determination of user-defined arbitrary analysis zone or
AOI (Area Of Interest), corresponding to TAZ (Traffic Analysis Zone) in GIS-T and real-time GIS database updating such as road
boundary, centerline and other target features on the scene. Therefore, after user selects AOI and updates database, these indices can
be easily computed using implemented program in this study. By this approach, new quantitative information to characterize an
urban transportation environment in a certain region can be easily obtained and utilized as meaningful indicators related to
transportation planning process or urban planning, comparing with those results produced without high-resolution imageries.
1. INTRODUCTION information to delineate a given network structure, and shimbel
index, circuity/connectivity/accessibility in the matrix form.
Especially, these GIS-based spatial metrics are known to
As various types of engineering applications dealing with provide useful quantitative information for urban transportation
geo-spatial imagery such as commercial uses of high-resolution
satellite imagery are possible, analytical GIS-based technology
on geo-spatial imagery has been studied. Utility of geo-spatial
imagery in the applications for urban transportation analysis,
which often refers to GIS-T (GIS for Transportation) and GIS
network analysis functionalities, is regarded as one of these
approaches (Khuen, 1997; Lang, 1999; Donnay et al., 2001;
Miller and Shaw, 2001). Most analytical functions in GIS-based
network analysis are based on problem-solving methodology in
the transportation geography (Han, 1996; Chou, 1999).
Lo and Yeung(2002) summarized that there are two main
groups in measures for network analysis in the geography: one
is to extract overall characteristic based on a topological graph
or topological graphs, and the other is to compute the shortest
or optimal path finding and allocation segments. Currently,
most commercial geo-processing software systems provide
network analysis modules. However, feasible functions to
extract basic quantitative indices for transportation network
structure in a certain region are rare in those systems. Recently,
some studies to implement fundamental functions using geo-
spatial imagery based on GIS have been carried out and
tentatively tested (Lee, 2002; Lee ef al., 2003).
Main focuses in this study are on implementation to extract
basic connectivity indices related to transportation network:
alpha index and gamma index, which are known as fundamental
analysis, and each index provides individual significance to
interpret a given network structure. Geo-spatial imagery
including high-resolution imagery or digitally processed
airborne photograph can also be effectively used as a base
image in these applications.
In this study, an extension program for automatic
computation of those indices is newly implemented in
Avenue!", as AVX extension programs running on ESRI-
ArcView® GIS. These extension programs in AVX-complied
are different from other ones such as (Ormsby and Alvi, 1999)
and Lee and Wong (2001). On application of this program, it is
designed that spatial database such as road centerline or
network structure with nodes and administrative boundary is
needed as the user-sided minimum requirements. Some case
studies regarding practical application of these programs are
presented mainly with KOMPSAT EOC.
2. TYPES OF QUANTITATIVE INDICES FOR
TRANSPORTATION ANALYSIS
2.1 Connectivity Indices and Shimbel index
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