Urban expanding process along the transport corridor and the policy framework in Nanjing, China

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Urban expanding process along the transport
corridor and the policy framework in Nanjing,
China

• Chen Shuang, Sophia
• Nanjing Institute of Geography and Limnology,
  Chinese Academy of Sciencies
• Email schens_at_niglas.ac.cn

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Introduction

• During the past two decades, cities in the
  Yangtze River Delta have undergone rapid spatial
  expansion in relation with economic progress and
  population concentration in this area.
• The fast urban growth diminishes arable lands and
  ecological habitats as well as generating
  damaging effects through such sources as
  pollution and human use.
• Urban processes must be studied in order to
  understand their influences and minimize the
  negative effects on surrounding environment.

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Preliminary hypothesis

• The urban area generally extends from the centre
  outward with the form like a fried-egg. The
  expansion process is presumed to follow the
  cycled phases of expansion along transport
  corridors and filling space between the corridors.

Gu et al., 2000

• Rather than land price, policies and residential
  or firms preferences determine land development
  and land allocation due to the municipal
  governments monopolisation of land supply in
  Chinese cities.

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Objectives

• Quantitatively describe urban expansion process
• Investigate trends in land development patterns
• Determine to what extent the land policy and
  planning affect land development.

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Urban expansion of Nanjing
1986 Build-up area
1996 Build-up area
2002 Build-up area
Vegetation
water
Area (km2) Population (person) Population density (persons per km2) GDP per person (US dollar)
Nanjing 6582 5,836,000 887 4130
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Urban Nanjing image 2005
??-?? Pukou-Zhujiang new town
?? Xianlin new town
?? Dongshan new town
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Location of study area
South site North site
Delineation Along the airport highway lasting about 27 km from the city wall, 3 km buffer from the way Along the Nanjing-Luhe freeway lasting about 27 km from the Yangtze River, 3 km buffer from the way
Area 167 km2 160 km2
Administration Yuhua District Jiangning District (formerl Jiangning county) Pukou district Luhe district (original Dachang district)
Land / planning management District government Municipal government
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Index and data sources
Description indicator Definition Data sources
Urban intensity (UI) Developed urban area / total area 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
Urban expansion speed (UES) Developed area in a period / years 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
Land development structure (LDS) Ratio of residential, public service, industrial etc. land use types to the total developed urban area 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
Land use efficiency (LUE) Built-up area / the total area of developed land 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
Urban expansion track (UET) A series of gravity centre of developed land parcels in different periods. 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
Mean area of newly developed land parcels (MANDL) Mean area of developed land parcels in a period 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
Adherence of newly developed land parcel to the built-up area (ANDL) The mean value of developed land parcels nearest distance to the built-up area in a period. 1986, 1996, 2002 Land use data in shape file interpreted from TM images of Nanjing 2005 Sport 4 satellite image of Nanjing 150000 topographic map of Nanjing Satellite Image Atlas of Nanjing, 2005 Urban master plan of Nanjing 1981-2000 Urban master plan of Nanjing 1991-2010 Urban master plans of Pukou, Luhe, Dongshan 2002-2020
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Changes of UI and UES
Nanjing city

• The urban area extended at a faster speed in the
  two sites comparing with that in the whole city,
  indicating development concentration along the
  transport corridors.
• The expansion speed was accelerated from
  1996-2002 both for the south site and the whole
  city.

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Land development structure
South site
North site

• For the developed land parcels in the three
  periods, residential/service land use occupied
  about 30-70, industrial land use occupied about
  10-50, and the other was mixed land use and
  unused land.
• Industrial development within 1996-2002 and
  campus development within 2002-2005 were the
  major approach to urban expansion besides
  residential development.

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Land use efficiency

• A lot of land has not been used in the developed
  parcels during the fast expansion period. The
  efficiency decreased from over 96 to about 68.
• The rapid expansion in the south site is
  attributed to land enclosure to some extent.

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Landscape indicators

• The area of land parcels tend to be smaller
  pieces and the distance to built up area tend to
  be shorter in relation to adoption of compact
  development pattern.
• For the two sites the land parcel was located
  within 3.5 km to the built up area.

South site South site South site North site North site North site
86-96 96-02 02-05 86-96 96-02 02-05
MANDL (hectare) 66.97 73.59 18.59 56.13 18.52 18.04
ANDL (m)
Mean 379.33 661.14 88.26 79.89 38.76 55.47
Max 1940.31 3525.48 1115.21 1288.91 761.183 841.724
Min 0 0 0 0 0 0
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Urban expansion track
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Trends of land development patterns

• The expansion speed tend to slow down after the
  irrationally quick urban development within
  1996-2002 according to the UI and UES changes.
• Residential and public service including campus
  development have been becoming the major approach
  of urban expansion by the analysis of land use
  structure.
• The compact land development pattern tend to come
  back based on the land use efficiency calculation
  and the landscape indicator analysis.

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Effect of planning on land development

• Comparison of practical land allocation to the
  planning
• 80-98 of the two sites was not covered by the
  master urban plan within the fast expansion
  period.
• About 50 of the development covered by the plan
  differed in land use type.
• The coherence frequency tended to be improved.

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Effect of policy on land development pattern

• Differences in development pattern between the
  two sites with variant management systems

South site (1986-2005) North site (1986-2005)
Management system Local decision-making in planning and land supply Municipal decision-making in planning and land supply
Speed 3.30 km/yr 1.68 km/yr
Structure The portion of campus land have been increasing and that of residential land decreasing. The portion of residential land have been increasing
Efficiency of land use 80.18 89.36
Landscape Messed layout, each type of land use parcels equally distributed at two sides of the transport line Cluster layout, each type of land use parcels relatively concentrated and the homogenous clusters scattered in the site
Planning Low efficiency Effective
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Conclusion

• The high resolution satellite images provide
  abundant data for quantitatively analysis of
  urban expansion process in China. The research on
  quantitative description of urban expansion and
  its driving forces is important and realizable.
• The local government largely influenced urban
  land development but the decision maker are short
  of relevant supporting knowledge of land
  allocation.
• Residential/firms preferences for transport or
  amenity would be studied later quantitatively.

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The End and Thanks!