gis-based evaluation on the reconstruction of urban

The CRIOCM 2006 International Symposium on “Advancement of Construction Management and Real Estate”

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GIS-BASED EVALUATION ON THE RECONSTRUCTION OF URBAN-VILLAGES——CASE STUDY OF GUANGZHOU

Zhi Gang WU1, Su Hong ZHOU2, Rui Bo ZHOU2, Chen CHEN3

1.Graduate School of Landscape Architecture, Peking University, Beijing 100871, China 2.School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China 3.Department of Urban & Regional Planning, Peking University, Beijing 100871, China

Abstract: This paper intends to find a solution to evaluate the reconstruction of urban-village effectively. Urban-village is a phenomena which has to be solved for the urban sustainability associated with the acceleration of urbanization in China during the transitional period. Reconstruction is one of the solutions to be carried out by the government, but in which there are many complicated problems concerning the housing compensation, social security of the local habitants and land revenues of the sites. Evaluation on the basic situation such as cadastre, quantity and quality of the houses which to be dismantled will be the most important things before reconstruction. It is usually the difficult jobs for a traditional way. GIS technology has made it easy and helpful to evaluate the reconstruction projects. Taking a case study of Guangzhou, it proves that GIS technology has played an active & effective role in the urban regeneration including evaluation and decision-making. Some suggestions about the further applications in urban regeneration have been proposed afterwards. Keywords：GIS-based; Evaluation; Reconstruction; Urban-villages; Guangzhou

1 Introduction

Urban-village is a geographic phenomena in which there are remaining village houses and rural management organization encircled by the modern urban buildings (See in Figure 1) due to the accelerating urbanization and dual land system in China. It usually causes many social problems such as drugs criminals, fire-escaping obstruction and bad environments etc just like an urban slum. At the same time, an irrational and extensive

Figure 1 A bird view of urban-village in Guangzhou ( photographed by Li Junfu)


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land use in the urban-village has made the urban development un-economical and out of efficiency. The Municipal Government has taken these problems more and more seriously in many cities of China. The solutions for the urban-villages have attracted particular interests of the scholars and governmental officers in recent China, concerning the fields such as social connectivity (Li Peilin 2000), the approaches to renovation (Li Junfu 2004) and the coordination among the urban development, original habitants & the government policy (Wu & Zhou 2005) etc. Most of these research are about the social or economic analysis, and there lacks of workable measures to promote the regeneration of urban-village with a concrete technology for the planning design.

Reconstruction is one of the solutions to the urban-villages regeneration, in which there are many complicated problems concerning the housing compensation, social security of the local habitants and land revenues of the sites. Evaluation on the basic situation such as cadastre, quantity and quality of the houses which to be dismantled will be the key things before reconstruction for all of these will take a great amount of cost.

This research aims to propose a GIS-based evaluation of the reconstruction place including cadastre, quantity and quality of the houses in order to make the planning design and construction cost more reasonable. It proves that this evaluation plays a helpful role in decision-making for the government and planners.

2 Materials and Methods

2.1 Case background

The study case is situated in the central area covering 34ha of Wenchong, which is a village of more than 6000 original residents, located in Huangpu district where is on the east of Guangzhou. The village occupies a total area of 10.58 square kilometers, and has a history of more than 500 years. This research takes Wenchong village, one of the. experimental projects of Guangzhou Government, as a case to study the comparison amongst the different alternatives of planning design and implementation. The Basic information about Wenchong is described as in Table 1

Table 1 The Basic information about Wenchong Village

Rural Residence 3345 Urban Residence

2909

Populations (Census in 2001)

floating 15000

Total (km2) 10.58 Land Proportion of the construction

60％ Occupied Area

Extent of the case (ha.) 34. The base-ground Area to be

Dismantled 1286000M2 Area to be renovation

Total floors Area To be dismantled 2450000M2

Residence (Yuan per M2) 10 Current rent within the zone to be

reconstructed Commerce (Yuan per M2) 35

Residence (Yuan per M2) 1500

The expected compensation by the Residents

Commerce (Yuan per M2) 4000


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2.2 Research framework

The basic workflow can be described as following: An extensive investigation on the Wenchong village about land use and housing cadastre, compensation for the demolishment and the input-output of the reconstruction ; Establishment of GIS database including property of land & housing , construction cost, and social-economic factors etc; Analysis and evaluation of different planning designs considering input-output return period, the acceptance of the residents and the feasibility of the technology and so on; Selection of the optimal planning design for reconstruction. The applied methodology is summarised in Figure 2.

Figure 2 Research framework

2.3 Data collection

The data resource is based on the aspects as following: cadastre from the government; Site investigation on the individual housing; Data of the society and economy from the statistical department; In total, 1135 questionnaires were distributed, of which 1037 were returned and 1020 proved valid. In addition, more than 50 interviews were made with local government officers and stakeholders. This extensive investigation gave us a clear insight in the current land-use and housing in the research area.

3 Analysis and Evaluation Based on the GIS Database

GIS database has played an active and important role in the evaluation on the reconstruction planning designs, in which there are many complicated works including analysis of cadastre, the current land use and housing, the amounts of the floor areas to be dismantled, the compensation for the residents and calculation of the input-output return period etc.

3.1 Evaluation of the Quality and Quantity of the Current Buildings

(1)Quality This message can be used for the cost estimation of dismantling for there are different compensations varying with the quality of the buildings. The quality is assessed according to its structure style, material standard and used span of year. All the buildings in the research area have been classified to four


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levels with different color as shown in Figure 3. (2) Quantity The basic information of the current buildings including building coverage density,

ground-occupied areas, total floor areas, average stories and cubage ratio. The historic and featured buildings have been marked to be preserved.

3.2 Evaluation of the property right of the Buildings

Because of the standard for the compensation of the dismantled buildings is closely related to the property right and its legal registration, we established a GIS database for this information as shown in Figure 4 in order to evaluate the feasibility and cost of the reconstruction planning designs.

3.3 Integrated Evaluation of the Blocks

Considering the terrain and site condition, we divided the planned area into several blocks and made a GIS-based evaluation concerning the construction density, intensity, average floors and quality of the buildings etc. This evaluation shown in Figure 5 will be helpful and worthwhile to make the planning designs for reconstruction.

4 Evaluation on the Selected Planning Design for Reconstruction

4.1 The Reconstruction Plan

Based on the above evaluation, considering the integrated factors such as the demands of urban planning and infrastructure, and the compensation cost for the dismantled buildings, we proposed several planning designs to be compared and selected, one of which the schedule of the reconstruction and preserved areas have been made as shown in Figure 6.

Figure3 The Evaluation of the Current Buildings in the Research Area


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4.2 Cost Estimation of the Compensation for the Dismantled Buildings

Based on the GIS database, the amount of floor areas to be dismantled and the building areas to be used for re-settlement of the residents have been calculated, then we can make the cost estimation of the compensation and decide the developing intensity of the blocks so as to re-settle the residents and spare some buildings to be hired for the refund of the investment effectively.

Figure 4 The Property Right of the Building in the Research Area

Figure 5 Integrated Evaluation of the Blocks


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Figure 6 The Schedule of the Reconstruction

Figure7 Analysis of the Input-output Return Period for the Selected Planning Design

4.3 Selection of the Optimal Planning Design

We take a circular calculation for different planning designs to find out an optimal selection considering the investment input-output return period, the urban planning control and the demand of re-settlement of the residents in the reconstructing areas. One of which process can be described as shown in Figure 7.


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5 Discussion

GIS technology has been widely used in the fields of urban planning and management, while making a great deal of progress in the urban transportation and land use. In the urban reconstruction, there are many complicated problems concerning demolishment, re-settlement of the residents and the input-output benefits of the investment which will make very difficult jobs and inefficacy to evaluate the selected planning design and its implementation if using a traditional way. GIS technology application in the evaluation considering social-economic factors, basic cadastre information and the input-output return period of the investment has effectively provided a reasonable and believable criterion to select an optimal planning design for the urban reconstruction. In this research, a new approach to evaluation of the planning designs has been proposed, integrating the social-economic factors and the technology parameters of the site information to compare amongst the selected urban reconstruction projects for the government and the planners.

In recent years, GIS application has widen the eyesight of the urban researchers, and made the integration with micro-level of society, behavior & psychology and macro-level of physical space, as well as the integration of static description and dynamic simulation (Betty and Xie 1994). GIS application in the social investigation has attracted more & more scholars and officials, and become one of the most active trend of urban studies, with algorithmic model and analysis of social-economic condition. This research will be one of the efforts, and be use for reference to urban construction & management in the future.

Acknowledgements

This paper is supported by the National Natural Science Foundation of China grants 40401019 and 40471051, and Natural Science Foundation of Guangdong Province grant 04300547.

References

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(In Chinese)

gis-based evaluation on the reconstruction of urban

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