A Generic Data Model Proposal For Multi-Dimensional Road Object
H. Demirel
Istanbul Technical University, Division of Photogrammetry, 34469, Ayazaga, Istanbul
hande.demirel@itu.cdu.tr
WG IV/I — Spatial and Temporal Data Modelling and Analysis
Keywords: GIS, Databases, Modelling, Three-dimensional, Netwo
Abstract:
A new, generic approach to t
study . The current status, which is analyzec
problems and the success of the implemented systems are not cle
where it can be static or dynamic, referenced to one, two, three or four-dimension.
del the real world. These problems mainly conclude insufficient user requirement responses,
limits the ability of GIS to effectively mo
unpredicted data integration problems and finally lack of efficiency. This generic
models, since it bases on the decomposition of geometry, topology and thematic data.
/ork in order to comprehend the user assessments. The data model is designed
vy, road events and metadata. The first priority is given into geometry, where
traditional planar, centerline based, transportation netw
with four distinct components; being geometry, topolog
current models mainly emphasize on the thematic data compone
Topology, being non-planar and having abstraction levels, is modeled as a logic
developed methodologies, one-dimensional road information is transformed into thir
are successfully implemented using the integrated approach in one
o different GIS software are utilized and results are evaluated.
designed concepts
During the implementation of the concepts tw
1. Introduction
Due to the complex management tasks, the demand for dynamic
and multi-dimensional GIS is increasing rapidly, especially in
application areas of cadastre, transportation, urban planning and
environmental systems. Among these applications, the
transportation sector has different demands for dynamic and
multi-dimensional GIS, since these two challenging topics
promote the required data integration. In transportation
applications, data integration not only enhances the efficiency
of conducted applications, but also makes possible the
necessary dataflow within the agency. Spatial information
technology can be used as a logical and physical data and
method integrator necessary to the highway sector. Due to such
benefits, this technology is highly appreciated and widely
implemented. Conversely, the wide spread usage accelerate the
identification of problems, limitations and inadequacies of the
current systems. In order to achieve a wider perspective and
highlight the current situation within highway agencies, the
study is conducted at four countries namely; Turkey, Denmark,
Germany and the U.S.A. (Demirel,2002) Concentration is
mainly given to the following topics: organization structure,
user requirements, spatial data acquisition techniques, system
architecture, existing information systems and the conceptual
data models.
In the frame of this paper the current problems of spatial
highway information system is clearly outlined. Within these,
problems related with inadequate handling of multi-
dimensionality is going to be emphasized. In order to diminish
the problems, to provide the integrity and the efficiency, a new
conceptual data model is going to be introduced, which ensures
integration of all relevant data and business operations for the
entire agency. The designed concepts are implemented on a
pilot project and results are discussed.
he conceptual data modeling of multi-dimensional highway information system is pr
| in various countries namely; Turkey, Denmark, Germany and the U.S.A, reveals many
rks, Facilities, Status
esented in this
ar. The multi-dimensionality of road object is generally ignored,
Furthermore, the restriction of current data models
approach diverges from the current conceptual data
It presents a considerable departure from
nt. The basic component geometry is defined in third dimension.
-al abstraction of geometry. By means of the newly
d dimension and integration is achieved. The
object-relational system on a pilot project.
2. Current Status
The complex mission of highway agencies requires diverging
tasks to be accomplished by means of various methods,
depending upon required generalization level and quality of
information. In order to perform complete analysis. data
exchange between divisions is necessary and analysis involving
several divisions are common (Demirel, 2002). Existing data are
usually managed with databases and technologies that cannot be
integrated due in part to the lack of a comprehensive model for
location referencing data (Koncz and Adams. 2002). During the
study, it is examined that, many benefits of GIS technology are
not recognized, demands of the organization cannot be fulfilled
and the efficiency of spatial technology is mainly under
estimated. Even in some situations existing systems have not
been updated since the system implementation.
Since the data used by the highway agency mainly have spatial
character, several additional problems emerge. The parallel
usage and maintenance of several systems, requires collection,
modeling and maintenance of spatial information redundantly,
increasing the costs of the implemented systems and reducing
the efficiency. The spatial data acquisition requires the highest
efforts and costs, due to the high level necessity of
completeness, actuality, correctness and well-defined data
structure (BILL, 1999). Although, the well-defined data structure
is obligatory, conceptual data models of the implemented
systems are not formally designed and documented. Software
vendors’ proprietary databases are used for storing spatial
information. Other information sources, such as existing
databases, are then linked to the system as non-spatial
information. However, due to the nature of road object, these
sources include multi-dimensional spatial information.
1312
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