With the increased rate of rural-urban migration and population growth in the present years, study of urban development has gained a lot of momentum. As a result of these two basic phenomena the city tends to expand outwards to accommodate the ever increasing population pressure on the confined land resources. This process is termed as sprawl.
Any land use pattern that has low values on one or more of eight distinct dimensions of land use patterns, density, continuity, concentration, nuclearity, diversity, proximity and centrality is to be considered as sprawl (Galster et al. 2001). Sprawl must be considered in a space-time context; not simply as an increase of urban lands in a given area, but the rate of increase relative to population growth. Sprawl may be said to occur when the rate at which land is converted to non-agricultural uses exceeds the pace of economic development.
Not only is the amount of rural land lost to sprawl a key issue from an environmental and agricultural perspective but the amount of rural land loss and urban expansion is also significant to the quality of life of urban dwellers. The larger an urban area, the more difficult it will be for the average resident to reach the open spaces beyond the urban perimeter, the increase in urban distances can also affect commuting time and mobility.
Importance of GIS and Remote Sensing in Urban Planning:
The spatial depiction of the public amenities and infrastructural facilities can be made quite user friendly with application of GIS. This also holds true for the private organizations as they can chalk out the consumer load, the paying capacity of the consumers in different region and develop the organization accordingly.
{sidebar id=289 align=right} Real time traffic data combined with accurate maps can be very effective in reducing the response time for emergency services. Also GIS can help determine spatial and temporal distribution of natural resources and type of activities that are damaging the natural wealth of the nation. With this information the authorities can take preemptive steps in specific regions to promote the cause of conservation of natural resources. Similarly spatial demographic information combined with land usage can be used to determine the land price hike and for setting the economic policies of the region.
GIS can also be applied to the relatively newer concept of multilevel parking needs in the developing nation. This is important because even relatively smaller urban centers (like Udaipur, India) are experiencing severe parking pressure in certain areas, forcing the consumers to walk for kilometers, in turn hurting business and increasing pedestrian accidents.
GIS can help in providing information about crime rate and types of crime in the various city-sectors and in different cities. This information should be mapped and made available on the internet. This would make people aware and help them take judicious decisions about their movement across different parts of the nation. Several cities across US provide regional crime database to citizens. Making such information publicly available also promotes competition among the authorities of different cities, because best talent and companies would like to establish themselves in the safest cities.
GIS and remote sensing techniques can also help in tackling problems related to traffic, encroachments, air and noise pollution water and power supply etc. If the relevant spatial information is made available to the planners, they can take much better and fine grained policy decisions to solve these problems.
Application of GIS and Remote Sensing to Study of Urban Sprawl: Case Study of Udaipur, India
{sidebar id=337} The Study Area: The Udaipur and its environs, which is taken as the study area, is spread over a territory of 508.75 km2 and covers sixty seven villages in the vicinity of the Udaipur city with extension of 240 30’ to 240 40’ N and 730 37’30” to 730 52’ 30” E (Figure 1).
Process of Urban Sprawl: One of the prerequisite for understanding urban sprawl is successful land use change detection. Spatial analysis is done using GIS to chalk out the potentials and restraints of the region (Figure 2). This is made possible by accurate registration of the satellite imagery so that the overhead pixels represent the same location as the base map. There is a wide range of techniques used for land use change detection to study urban sprawl. The technique employed in the given study is based on the comparison of the classified images.
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To work out the temporal land use change following Landsat satellite imagery were used.
1 — Landsat MSS acquired on 23rd Sept., 1972
2 — Landsat TM acquired on 19th Oct., 1990
3 — Landsat ETM Plus captured on 22nd Oct., 2000
The analysis is categorized as: prior to open door policy i.e., year 1972 to 1990 and post economic reform i.e., year 1990 to 2000. The remote sensing data was acquired by Global Land Cover Facility. Erdas Imagine software was used for land use classification. Firstly different bands of the imagery were stacked to produce a false color composite. The area of interest was calculated; the required image was extracted by sub-setting of the image and then re-projected.
{sidebar id=339} To detect the land use change, comparison of classified images was done. The process consists of displaying the rectified imagery on the screen and digitizing the polygons representing different land use categories. The categorization of land use attributes is based on image characteristics such as tone, texture, color and pattern. The subset image was interpreted with reference to ground verifications wherever required.
Each image set has been broadly classified into five different categories viz., forest and scrub land, built-up area, water, crop land and barren land. The polygons were identified by independent labels attached to the centroid of each polygon. These polygons were labeled as training sites.
Thirty confirmed training sites per land use category were selected using signature editor and the values were merged to give an average pattern for the category. The signatures were then assigned conventional colors based on standard theme. These signatures together with the subset image formulated the supervised classification.
Magnitude, Growth and Trend of Urban Sprawl: The growth and trend of urban sprawl is analyzed with help of change in the percent of various land use categories during the period. Table 1 describes the period of eighteen years from 1972 to 1990 illustrating an increase of 9.8 percent in the built-up land. Substantial increase of 37.54 percent is also reported in the barren land. This depicts that the land has been cleared and sold out in the commercial market where the infrastructural development is yet to take place.
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The period 1990 to 2000 depicts a remarkable increase of 51.77 percent in the built-up areas which shows how the open door policy, relaxation in trade norms, quotas and tariffs, flow of foreign investments resulting from the economic reforms in India that boosted the process of urbanization.
With the upcoming multiplex, residential townships, call centers, MNC’s, shopping malls and related trade sector activities in the region large chunks of land have been consumed, engulfing more and more of the crop and cultivated land through the process of urbanization. The study is therefore an important step towards realizing that the land acquisitions are taking place at a fast rate (Figure 3).
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Table 2 clearly depicts around 12.92 percent of the forest and scrub land is transformed into either the built-up area or barren land. Around 20.58 percent of the crop land been transformed into built-up land or barren land. This implies that the urban expansion and growth is adversely impacting the green belt and agriculture of the region. Around 16.50 percent of crop land and 9.52 percent of the forest and scrub land has become barren land which means that the land has been cleared and sold for further expansion but the construction activities are yet to take place.
Land Suitability Analysis and Alternative Land Development Plan
Land suitability was performed to develop a plan that would make this city sustainable. Land suitability analysis was carried out using Arcview GIS Spatial Analyst. This suitability analysis was based on three major parameters namely, slope of the region, stream buffer zones and the existing land use (Figure 4). Prospective growth sectors are determined by overlaying these major parameters and other socio-economic infrastructural data of the region.
The data is loaded as themes which were converted into discrete grids. The land suitability was derived using weighted overlay technique whereby land use was given fifty percent weight, slope thirty percent and stream buffer twenty percent weight inferences. The land use was categorized into barren land, crop land, built up area, water and forest and scrub land. The scale was predefined at one to five with land suitability decreasing as we go from one to five.
The city area especially the walled city within the city limits has shown the best suitability for development. Despite rugged terrain the areas surrounding the upstream lake bodies show very good prospects of urban development but the bye laws safeguarding around 500 meters around the lake bodies. Other areas depicting best suitable sites include the major transport artery i.e., along National Highway-8 (Figure 5).
{sidebar id=340} The region with moderate land suitability lies at the base of the high hills and can be developed as recreational centers, for trekking, mountaineering and sports tourism. Protected forest areas are mostly the areas which have been conserved on high slopes to enrich the scenic beauty of the region, enhance the tourism prospects and develop greener sustainable city. Looking into the cultural factors influencing the pace and trend of urban development it is found that generally the larger settlements with high population have stronger attraction forces of land suitability and urban development.
Few villages namely Sisarma, Hawala Kalan and villages on the north-west of Fatehsagar Lake have poor land suitability prospects. Conversely, there are patches of land which are comparatively more suitable but have no major (revenue) villages. Authorities should consider development of these areas.
{sidebar id=341 align=right} This alternative land development plan takes into account the possibility of revenue settlements along the major transport network. The existing network of the transport arteries is mostly along the developable land segments and show a potential of expansion towards the region of poor land suitability.
Some of the villages lying in the poor land suitable sections presently do not have strong connectivity. But some of the segments which have high suitability and good connectivity lack a strong pull factor due to smaller size of settlement. The segments of very poor land suitability can be made as the waste disposal and dumping grounds as those are most unsuitable for urban processes.
Figure 6 depicts prospective growth sectors along with the activities that can be developed in each sector as an approach towards alternative land development plan for a sustainable urban development (Figure 6). It is suggestive of a balanced development where green environs are maintained along with the city development. The development of major residential colonies nearing the city limits provides access to basic services for livelihood. Industrial and mining sector needs to be developed in outer limits and fringe areas mainly along the transport arteries. Educational sector has shown a rapid expansion towards the eastern side and can be developed as a continuous belt with institutions along with hostels.
{sidebar id=342 align=right} All the transformation and encroachment of land is mainly governed by its accessibility, availability and value. These phenomena interact with each other and give rise to redistribution of land through complementary tendencies of concentration and dispersion.
Further Directions: This case study depicts the process and pattern of urban sprawl. When such study is incorporated with the infrastructural developments and amenities of the city using GIS, urban planners can extrapolate the growth patterns several years in the future. The urban quality of life and facilities management in urban area is one of the major concerns that unplanned urbanization has created across the globe. The world is well aware of the harmful implications of urbanization. It is the need of the hour that the developed nations and developing nations move hand in hand to tackle this issue and successful developmental models are followed across suitable urban centers.
Implementing a web-based GIS database is the best way to improve access to the GIS data. Also better training and networking among GIS professionals would encourage the sharing of high quality spatial data. Insufficient user support, lack of proper hardware and software, unavailability of GIS professionals, unreliable power supply, and slow and limited internet access are the major hurdles prohibiting widespread use of GIS technology especially in developing nations.
Efforts should be made to bring this digital technology more widespread in educational curriculum. GIS researchers should take up the challenge of converting paper based spatial data to web accessible electronic indexed database. Pilot projects should be encouraged globally to evolve viable processes.
References:
— Cheng, J. and Masser, I. (2003) Urban Growth Pattern Modelling: A Case Study of Wuhan City, PR China, Landscape and Urban Planning, 52, pp. 199 – 217.
— Fang S., Gertner G. Z., Sun Z. and Anderson A.A. (2005) The Impacts of Interactions in Spatial Simulation of the Dynamics of Urban Sprawl, Landscape and Economic Planning, 73, 4, pp.294-306.
— Fazal, S. (2004) The Role of Accessibility in Urban Land Transformation: A GIS based Study of a Growing Urban Center in a Developing Economy, Asian Profile, 32, 1, pp.61-76.
— Galster G., Hansan R., Ratcliffe M., Wolman H., Coleman S., and Freihage J., (2001) Wrestling Sprawl to the Ground: Defining and Measuring an Elusive Concept, Housing Policy Debate, 12, pp. 681-718.
— Jain, M. (2009) Remote Sensing and GIS Techniques (A Case Study of a Developing Urban Center), Himanshu Publications, New Delhi, ISBN: 978-81-7906-160-2.
— Jothimani, P. (1997) Operational Urban Sprawl Monitoring using Satellite Remote Sensing: Excerpts from the studies of Ahmedabad, Vadodara and Surat, India, Paper presented at 18th Asian Conference on Remote Sensing, Malaysia.
— Turkstra J. (1996) Urban Growth and Land Use Options for Lower-Income Groups: A Case Study of Villavicencio, Columbia. ITC Journal, 1, pp. 57 – 63.
— Yeh, A. G. O. and Xia Li (1996) Urban Growth Management in the Pearl River delta: An Integrated Remote Sensing and GIS approach. ITC Journal, Special Habitat-II Issue, 1, pp. 77-86.
