Urban Rail Transit Demand-Supply Study – Based on GIS and Space Syntax A case study of Hangzhou City WU Yi-zhou 1 ,CHEN Xue-wei 2 ,ZHU Jia-yi 3 (1. 2. 3. Zhejiang University of Technology, Hangzhou 310014, China) [Abstract] Early in the metro transit network construction, transit facilities and industrial layout are directly related to the efficiency of site operation. Choosing appropriate evaluation methods, and judging the supply and demand in the space dimension, can provide the scientific basis for further planning and design. This paper uses Hangzhou subway Line 1 as an example through space syntax model to conduct quantitative analysis research on the 31 railway stations of Hangzhou subway line 1 which has inputs operations. Based on the metro transport accessibility evaluation, GIS-AHP method was applied, integrating current information and obtaining the space distribution characteristics of the metro transit requirements. Combined with the research data and spatial integration mechanism for interacting with metro transit demand, the paper provides further discussion of Hangzhou subway line 1 facility layout strategies and suggestions for its future development. [Keywords] space syntax;GIS; subway transportations;supply and demand of transportation 1 Introduction Layout of rail transit network based on the transport needs and the allocation rules of resources of urban space. However, the phenomena of transfer facilities does not match the traffic demands, traffic space disperseor even conflicts with spatial partitioning widely observed. In the critical period of the accelerated urbanization process, based on scientific and rational assessment of transport supply and demand, to further improve the layout of the rail network and supporting facilities is an effective way to improve the quality of China's urba nization. In the beginning of metro transit construction, the layout of transit facilities directly relates to the operations and using efficiency of each site. Actually it reveals a number of issues: some of them are located in the center of the cities, having strong attraction to get more industry agglomeration and space support because of the capacity on control and arrangement. While some of the sites are located in the new district or area of the relatively small proportion of built up region, all kinds of needs do not come in conjunction with functions of city causing a certain degree of resources waste. Worse still, it is not able to get more potential into the rail transit system if transfer facilities layout is not perfect. Therefore, under the new trend of urban rail transit development, the transport demand and traffic integration should be more closely connected, and planning ideas and methods should be more focused on providing the assessment of supply and demand to eventually achieve the goal of balancing transport supply and demand. Rail transit systems in the developed countries have been developed and the focus has been changed from the spatial distribution and transfer of resource allocation to performance evaluation and security issues. There are typically studies: Geertman and Ritsema (1995) evaluated the traffic network accessibility based on GIS and spatial potential model [1] . Raveau (2010) proposed a model for assessment of transit routes based on the elements like transfer time, cost and location [2] . Kumar Parida (2011) raised an evaluation model for transfer, built by five important safety factors and based on the data analysis [3] .Gordon (2013) evaluated the transfer of a bus, intercity rail and ferry based on cost of service systems. [4] As for the traffic supply issue, researches and practices from domestic scholars are concentrated on the introduction of the Western academic concept. Currently, there are several methods to assess the traffic network
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Urban Rail Transit Demand-Supply Study – Based on GIS and Space Syntax
A case study of Hangzhou City
WU Yi-zhou1,CHEN Xue-wei
2,ZHU Jia-yi
3
(1. 2. 3. Zhejiang University of Technology, Hangzhou 310014, China)
[Abstract]
Early in the metro transit network construction, transit facilities and industrial layout are directly related to
the efficiency of site operation. Choosing appropriate evaluation methods, and judging the supply and demand
in the space dimension, can provide the scientific basis for further planning and design. This paper uses
Hangzhou subway Line 1 as an example through space syntax model to conduct quantitative analysis research
on the 31 railway stations of Hangzhou subway line 1 which has inputs operations. Based on the metro
transport accessibility evaluation, GIS-AHP method was applied, integrating current information and obtaining
the space distribution characteristics of the metro transit requirements. Combined with the research data and
spatial integration mechanism for interacting with metro transit demand, the paper provides further discussion
of Hangzhou subway line 1 facility layout strategies and suggestions for its future development.
[Keywords] space syntax;GIS; subway transportations;supply and demand of transportation
1 Introduction
Layout of rail transit network based on the transport needs and the allocation rules of resources of urban
space. However, the phenomena of transfer facilities does not match the traffic demands, traffic space
disperseor even conflicts with spatial partitioning widely observed. In the critical period of the accelerated
urbanization process, based on scientific and rational assessment of transport supply and demand, to further
improve the layout of the rail network and supporting facilities is an effective way to improve the quality of
China's urbanization.
In the beginning of metro transit construction, the layout of transit facilities directly relates to the
operations and using efficiency of each site. Actually it reveals a number of issues: some of them are located in
the center of the cities, having strong attraction to get more industry agglomeration and space support because
of the capacity on control and arrangement. While some of the sites are located in the new district or area of the
relatively small proportion of built up region, all kinds of needs do not come in conjunction with functions of city
causing a certain degree of resources waste. Worse still, it is not able to get more potential into the rail transit
system if transfer facilities layout is not perfect. Therefore, under the new trend of urban rail transit development,
the transport demand and traffic integration should be more closely connected, and planning ideas and methods
should be more focused on providing the assessment of supply and demand to eventually achieve the goal of
balancing transport supply and demand.
Rail transit systems in the developed countries have been developed and the focus has been changed from
the spatial distribution and transfer of resource allocation to performance evaluation and security issues. There
are typically studies: Geertman and Ritsema (1995) evaluated the traffic network accessibility based on GIS and
spatial potential model[1]. Raveau (2010) proposed a model for assessment of transit routes based on the
elements like transfer time, cost and location[2]. Kumar Parida (2011) raised an evaluation model for transfer,
built by five important safety factors and based on the data analysis[3].Gordon (2013) evaluated the transfer of a
bus, intercity rail and ferry based on cost of service systems. [4]
As for the traffic supply issue, researches and practices from domestic scholars are concentrated on the
introduction of the Western academic concept. Currently, there are several methods to assess the traffic network
like the equivalent line method, distance method, space syntax and GIS of space analysis method. For instance,
Chen Mingxing and Shen Fei (2005) introduced space syntax theory, proposed two new variable, mastery
capacity and integrated degree, and put space syntax model into the quantitative of empirical research for city
traffic network[5]. Cheng Changxiu and Zhang Wenchang (2007) combined Metro features of conversion times
and took the form analysis variable of the average depth value in space syntax, quantitatively evaluating the
accessibility of subways in Beijing. Chen Shaopei, (2013) based on evaluation track traffic network space
connected, using ArcGIS platform of anti-distance weight plug value method generated equivalent line figure,
sketched out overall network of mastery space pattern and described its space features[7].
To recapitulate, it is extremely urgent to have appropriate assessments for transport supply and demand
assessment methodologies due to current issues on some cities of urban rail transit development and inefficient
public transport supply. This paper will discuss supply and demand characteristic of urban rail transit (Figure 1)
by using model site space syntax integration, considering the GIS-AHP model to assess the demand for rail
transport in the region, and taking into account the elements of reality.
Figure 1. Contradiction between supply and demand assessments of urban rail transit routes
2. Spatial integration analysis on Hangzhou Metro Line 1
2.1 Preparation
The urban transportation was taken from Hangzhou map (2013), running the Convert function in the
DepthmapX software, and doing Axial data conversion to get the spatial axes graph of Hangzhou. It is needed to
click on the Point/Axial/Convex button under Tools feature, select the Run Graph Analysis, set the RADIUS as n, 3,
6, 9, and also set the distance weights to build Hangzhou City axis model.
2.2 Analysis of global spatial axes
Choose K=n represents the Total Integration and use it to showing the spatial layout of traffic networks on
behalf of Hangzhou. K=n, means Total Integration, which can be understood as a 1/(Total Depth). In this function,
Total Depth represents the number of stepsapplied to all spaces. The higher the value of Total Depth is, the
worse the city integration becomes. Integration is based on the inner structure of self-organization and during
system evolution, this mechanism stimulates and interferes into the existing space, which refers to the spatial
logic between road network and the changes of social activities. Integration helps to measure potential of
attracting traffic, which refers to the accessibility.
2.2.1 Features of global spatial axes
Polycentric is beginning to form and it appears obvious partition. Axis map of Hangzhou, as shown in Figure
2, main cities, Xiaoshan, Linping and Xiasha constitute to the main skeleton of the district. The core is still
dominated by the West Lake. More road and bridge constructions strengthen the links between main city of and
sub-centers. However, a more stable urban transport network still requires a certain timeto develop and be
applied in the community.
In the areas along the rail transit, every center is associated with the main city characterized by integration
of spatial differences. Global integration spatially showed significant changes, in which the main site in main
urban own average spatial integration is at 0.6155, Xiaoshan is 0.5462 while Lin Ping-Xiasha gets 0.4252 (table 1).
According to the color changed, the connection between main city zones with Xiaoshan is faster than the other
two sub-centers.
Figure 2. Hangzhou global axis model (K=n)
Table 1. Spatial integration of regional rail transit stations
Zong Average Integration Range Average Depth Number of station
Main ci ty zone 0.6155 0.5197-0.7013 13.3765 16
Xiaoshan 0.5462 0.5169-0.5754 14.8849 5
Linpin-Xiasha 0.4252 0.3801-0.5103 18.9410 10
2.2.2 Connotation of global space
The characteristics of a polycentric system are obvious. It is not difficult to conclude from the integration
differences in spatial distribution, that Hangzhou urban spatial system is in growth and development. The
number of integrated axis appears different in each level, which means that the degree of polycentric
development brings sequential changes. Sub centers, especially in Linping-Xiasha, have the low degree of
integration, which means that the development potential of the area needs to be tapped. It is obvious that the
space connection between sub-centers with the main city zones is strong, and that the radiations from the main
city to the sub-centers are increasingly strong.
Main city occupies a dominant position in the global development of space. Hangzhou has made rapid
development over the past decade, especially with "Qiantang River times". Because of that, Xiaoshan District has
been greatly improved in urbanization. However, the urban spatial structure and texture are still incomplete. This
conclusion has the universality towards the urban spatial structure of majority cities. According to the influence
from the location of traditional city, the inner factors are still inclined towards traditional spatial agglomeration.
On the contrary, because of its own network is fully developed, the new nuclear from sub-status still stay at the
center of traditional polar to maintaining the regional space systems.
2.3 Analysis of local spatial axis
The paper selected K=3 on behalf of local spatial integration using bright colors to represent the main road
network structure for each partition. In the analysis of local space axis, we can compare the integration
capabilities of local spaces and discuss the differences of regional integration from a smaller perspective.
2.3.1 Features of local spatial axis
Local integration represents the location of each zone, differences of integration and spatial developed
morphology. From Figure 3 we can conclude that the main towns, Xiaoshan, Linping and Xiasha have their
respective center regions. Among of them, the major city shows a larger area and higher level of high degree
integration space. Formation of local integration and each zones sharing similar spatial morphology, which
reflects the spatial restriction has affection on city development, such as triangular shape in Xiaoshan,
semicircular in Xiasha.
High integration of regional is closely connected with Metro Line 1. Compared to the global integration,
local integration can better represent the leading role of Line1 in regional resources integration. Fastest-growing
district centers are organized to be together, resulting in the development of potential increased in the spaces
link along Line1. If we need to integrate the development potential from Yuhang, Sandun and Xixi de, we should
wait for the construction of the other rail lines in the region.
Figure 3. Hangzhou local axis model (K=3)
2.3.2 Connotation of global space
The obvious changes from Integration of district centers existed, but were influenced by the limited factors.
In the local axis model, the classifications of integration are more evident, which indicates that the main city zone
and all districts present self-organization of their space in the city development. Influenced by other constraints,
such as space constraints, facilities, etc, every district embodies very special spatial form, which also provides
some references for the future partition.
The tractive effort from Line 1 shows greater influence on local issues rather than global ones. Compared
with the global axes model, a local axes model is better reflecting the proper connection between regional
centers and the main city zones by rail transit. Meanwhile, the main city owns highly consistent between global
and local integration which suggests that Hangzhou has always maintained a well synergy with the whole space
system in the process of development.
2.4 Intelligence analysis
In order to study the integration of local and global space deeply, we use the Scatter Plot feature in
DepthmapX and select K=n as the horizontal axis, K=3 for a vertical axis to do the global intelligent calculation.
Then we selected K=6 as the horizontal axis, K=3 for a vertical axis to do the local intelligent calculation. From the
scatter chart, we can figure out the spatial distribution of integration from two models, and we can also conclude
spatial integration ability of two models based on the comparison with correlation coefficient (r).
Figure 4. Hangzhou global and local axes model of intelligent scatter spot model
By Figure 4, we can figure out that scatter models present obvious differences among the axes models. The
slope of the global chart is significantly less than local one and it indicates that during the current situation, the
development speed in local spatial is better than global space. Only when the local space develops to a certain
stage, appears both broadly similar growth conditions.
The intelligence of global axes model is 0.2914 while local is 0.8478. It turns out that global integration
capability of Hangzhou is weak, and has various regional differences. On the contrary, the integration capability
of local is strong and it has formed a certain center, which illustrates that other-organization and
self-organization mechanism[8]
from the outside still need some time to unified and promote the changes of
urban spaces.
2.5 Evaluation of spatial integration
Based on the characteristics and connotation of Hangzhou global and local spatial axis models, we selected
geospatial nearest the rail site sections, by calculating the average value (using the global axes model, that is, K=n)
reflect the spatial integration of each site’s condition (table 2).
The affection of Hangzhou global space development mechanism towards the spatial integration around the
rail transit stations is "top-down". "Top-down" refers to regional differences emerging from the urban
agglomeration of industrial spaces and activity spaces. There are no district that can get rid of large space texture
or break through the existing spatial structure and social order. Therefore, we use the calculation from global axis
model to represent the spatial accessibility of rail transit stations.
The affection from Rail transit stations set on Hangzhou local spatial development is "bottom up". "Bottom
up" presents the rail transit lines break through the limitation and make the city develop along the line and ease
the situation of a large number of industries to concentrate. More importantly, the spatial integration is
calculated by existing traffic network, which means that the conclusion represents the city spatial accessibility in
only short-term (5 years) or medium term (10). As time goes on, new urban areas will continue to ease pressure
on crowded old city and the regional spatial integration is bound to stimulate some changes. Thereby, we still
need to adjust transfer facilities, industrial distribution, development intensity and so on.
Table 2. Space integration and average depth of transportation stations