Landscape and Urban Planning 100 (2011) 223–230 Contents lists available at ScienceDirect Landscape and Urban Planning journal homepage: www.elsevier.com/locate/landurbplan A case study on the relation between city planning and urban growth using remote sensing and spatial metrics Hai Minh Pham a,∗ , Yasushi Yamaguchi a , Thanh Quang Bui b a b Department of Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Japan Department of Geography, Hanoi University of Science, Viet Nam National University, Viet Nam a r t i c l e i n f o Article history: Received 23 February 2010 Received in revised form 23 December 2010 Accepted 28 December 2010 Keywords: Urbanization Hanoi Landsat Image processing Spatial metrics a b s t r a c t Despite the unprecedented rate of urbanization around the world, information regarding land use planning and management is not updated frequently enough to accurately track this urban change In order to monitor changes in the urban environment, an understanding of the change in patterns of urban development over time is becoming increasingly important The objective of this study is to explore an approach for combining remote sensing and spatial metrics to monitor urbanization, and investigate the relationship between urbanization and urban land use plans The study areas, consisting of the cities of Hanoi, Hartford, Nagoya and Shanghai, were examined using Landsat and ASTER data from 1975 to 2003 In this study a program based on the PLADJ spatial metric was undertaken to produce urban growth maps Then, FRAGSTATS was used to evaluate the characteristics of urban composition The results showed that the urban core of Nagoya changed moderately over time Shanghai had a high population density, and satellite towns absorbed potential suburban development Hartford exhibited a spread out pattern of urban development with a high concentration of settlement in the suburb Conversely, the new urban areas of Hanoi developed rapidly along major transportation routes, resulting in urban development in Hanoi assuming an unusual pattern The combined approach of remote sensing and spatial metrics provides local city planners with valuable information that can be used to better understand the impacts of urban planning policies in urban areas, particularly in Hanoi © 2011 Elsevier B.V All rights reserved Introduction The population of the world is on the verge of shifting from being predominantly rural to urban As of 2008, more than half of the world’s human population has resided in urban areas, and by 2030, urban inhabitants will account for approximately 60% of the world’s population (Waibel, 1995) Urbanization can be defined as the changes that occur in the territorial and socioeconomic progress of an area, including the general transformation of land cover/use categories from being non-developed to developed (Weber, 2001) The rapid growth of the urban population has occurred in response to increased urban migration as people search for better jobs and improved living conditions Historically, urban immigration has increased at rates that have exceed those of infrastructure development in the destination cities, resulting in immigrants being unable to find suitable employment opportunities and subsequently becoming part of the urban poor This rapid ∗ Corresponding author Tel.: +81 52 789 3023; fax: +81 52 789 2523 E-mail addresses: haialas@yahoo.com (H.M Pham), yasushi@nagoya-u.jp (Y Yamaguchi), qthanh.bui@gmail.com (T.Q Bui) 0169-2046/$ – see front matter © 2011 Elsevier B.V All rights reserved doi:10.1016/j.landurbplan.2010.12.009 increase in urbanization and the concomitant effect that it has on land use means that it is becoming increasingly for city planners to adopt appropriate sustainable land use plans Planning and managing urban spaces depends on knowledge of the underlying driving forces, combined with the chronology and impacts of urbanization (Klosterman, 1999) City planners, economists and resource managers therefore need advanced methods and a comprehensive knowledge of the cities under their jurisdiction to make the informed decisions necessary to guide sustainable development in rapidly changing urban environments Remote sensing provides spatially consistent coverage of large areas with both high spatial detail and temporal frequency, which is useful for examining historical time series (Jensen and Cowen, 1999) Moreover, remote sensing data is effective to monitor the land use change in areas, especially where information on land use management is inconsistent and insufficient For example, recently the economic development in Hanoi impacts the land use change in the suburb occurring rapidly With the current land use map is updated every years, local land use managers have not enough information to monitor land use change of Hanoi Therefore, with increased availability and improved multi-spatial and multi-temporal resolution, remote sensing can now be applied to 224 H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 Fig Study areas in the same scale monitor and analyze urban expansion and land use changes in a timely and cost-effective manner On the other hand, spatial metrics are measurements derived from the digital analysis of thematic maps to show spatial heterogeneity at a specific scale and resolution (Herold et al., 2002) Such analyses provide quantitative characterizations of the spatial composition and configurations of habitat or land cover types, and can be used to track changes in landscape patterns over time (Henebry and Goodin, 2002) The combination of remote sensing and spatial metrics can provide spatially consistent and detailed information about urban structure and change, permitting more accurate representation and understanding of urban growth processes (Deng et al., 2009) The objective of this study was to validate the applicability of spatial metrics for characterizing urbanization in the cities of Hanoi (Vietnam), Nagoya (Japan), Hartford (Connecticut, USA), and Shanghai (China) In the previous study, we detected the expansion of Hanoi by using an image classification method (Pham and Yamaguchi, 2007) The results visually showed the urban change of Hanoi from 1975 to 2003 However, in order to have a better understanding about the history of Hanoi’s development process, the local land use planners raised the questions of quantifying where and when the urbanization occurred in the same period We developed the primary research to new direction, in which the result not only answered the questions of the local land use planners, but also provided various examples of urban change patterns as well as the policies to manage these changes Nagoya, Hartford, and Shanghai were chosen because of some reasons Firstly, the study wanted to compare the urban change of Hanoi and other cities in different countries Secondly, these urban areas developed very fast in the same period from 1975 to 2003 Moreover, the study areas have a particular relationship in terms of the topography The rivers running inside these cities as Red River (Hanoi), Connecticut River (Hartford), and Hangpu River (Shanghai) separate them to East and the West parts The successful land use planning of Hartford and Shanghais will be valuable for Hanoi to solve the gap of the urban development process between the West and the East of Hanoi due to the effect of the Red River While the primary focus was on urban development in Hanoi, we expected that the analysis of urbanization patterns in other cities is considered useful not only for Hanoi but also for Vietnamese policy makers and related officials to have appropriated local land use plans The surface land cover maps of the four cities were generated from satellite images using the classification methods described in Pham and Yamaguchi (2007) (Section 3.1) The ‘percentage of like adjacencies’ (PLADJ) was then used to quantify urban fragmentation and to generate urban change pattern maps (Section 3.2.1) The statistical program FRAGSTATS (McGarigal, 2002) was used to perform the PLADJ analysis (Section 3.2.2) Finally, the urban growth pattern maps and the FRAGSTATS results were used to analyze urban growth within the context of urban planning (Section 4) The results of this study are expected to assist local officials in their understanding of urban dynamics, and in so doing, promote future sustainable growth Study area and input data 2.1 Study area Hanoi is the capital of the Socialist Republic of Vietnam (Fig 1a) It is an ancient city located on the banks of the Red River and retains the Old Quarter, which has a history that spans 2000 years and represents the eternal soul of the city Hanoi was originally planned as a grid, with areas small residential houses located along narrow streets In 2005, Hanoi covered approximately 921 km2 (the study area covers 400 km2 ) and the population numbered approximately 3.3 million (Hanoi Statistical Yearbook, 2005) Recently, this high population density in the city centre has received considerable attention given that it is causing considerable pressure on the available land (Pham and Yamaguchi, 2007) Nagoya (Fig 1b) is an active business centre in Japan Located on ¯ the Pacific coast in the Chubu region with the population of over 2.2 million, the city has the greatest concentration of manufacturing industries in the country (http://en.wikipedia.org/wiki/Nagoya) The urban changes in Nagoya are evident in the considerable suburban sprawl associated of the city The city is unique in that there are large houses on lots that are generally larger than those found in other urban areas of Japan In this respect, the city appears to have followed the Western model more closely than any of the other large urban centres in Japan (Cox, 2003) With an urban population of million people, Greater Hardford (Fig 1c) located on the Connecticut River is the largest metropolitan area in Connecticut The rapid construction of the highways near the periphery of the city the late 1950s had a direct impact on the development of the city More recently, Hartford has become known as the “Insurance Capital of the World”, since the headquarters of many of the world’s insurance companies are located there After years of relative stagnation, Hartford has recently begun to attract new development, especially in the downtown areas (http://en.wikipedia.org/wiki/Greater Hartford) With the population over 17 million, Shanghai (Fig 1d) is one of the largest and most prosperous cities in China (Haixiao, 2000) The city is located at the mouth of the Yangtze River on H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 China’s eastern coast Since the Chinese government adopted the economic reforms of 1978, Shanghai has undergone dramatic economic growth and the increase in the population density of the inner city has resulted in extensive pollution of the city environment (http://en.wikipedia.org/wiki/Shanghai) One of the most notable achievements of the city’s urban plan has been the construction of the new Pudong New Area, which is located on the east of the Hangpu River, because it promotes the development away from the city centre In order to satisfy the transport demands of an estimated 70 million visitors to the Shanghai 2010 Expo, a considerable amount of investment is currently being channelled into the development of a transport infrastructure both within and between cities in the region 2.2 Data sources Sets of multi-spectral and multi-temporal satellite data for Hanoi, Nagoya, Hartford, and Shanghai were obtained for the years 1975–2003 from the Tropical Rain Forest Information Centre, Michigan State University, USA (Table 1) Cloud cover was less than 10% in all images and the visible and near infrared (NIR) bands used for data processing were rectified geometrically to a common Universal Transverse Mercator coordinate system 225 Table Data sources Hanoi Nagoya Hartford Shanghai 1975(MSS), 1984(MSS), 1992(TM), 2001(ASTER), 2003(ETM+) 1975(MSS), 1985(TM), 1996(TM), 2002(ETM+) 1979(MSS), 1989(TM), 2002(ETM+) 1979(MSS), 1989(TM), 2001(ETM+) Methodology 3.1 Urban area detection This study used mid-resolution remote sensing data (ASTER 15 m and LANDSAT 30 m) All the images were then resampled to the spatial resolution of 15 m We decided to resample the data to the spatial resolution of 15 m because of the relationship between the size of a pixel and the average size of houses in Hanoi, Nagoya, and Shanghai With the average size of houses less than 200 m2 , 15 m resolution data (one pixel in the image covers 225 m2 ) was expected to be a suitable resolution to study the urban change in these four cities However, detection of the edges of urban areas using midresolution data, such as ASTER and Landsat imagery produced a mixel problem In this study, the mix-pixel problem arises through Fig The urban area detection 226 H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 the mixing of three components, such as urban, vegetation and water land use types occurring within a given pixel In order to resolve this problem, this study applied the classification method of Pham and Yamaguchi (2007) to classify the urban areas This classification method is effective because it integrates the results of the image classification, the soil index, and the NIR band to detect the urban areas while concurrently resolving the mixel problem Image classification methods, such as this supervised maximum-likelihood method, are generally referred to as conventional change detection methods (Duong et al., 2002) While the obtained results successfully detected the urban area, the occurrence of the mixel problem remained In addition, although the soil index has the advantage of being able to distinguish between soil and water, it is difficult to differentiate between urban and fallow areas The soil index used in this study was derived from the vegetation-soil-water (VSW) index of Yamagata et al (1997) By combining the two aforementioned supervision methods we were able to delineate the urban areas and reduce the relative disadvantages associated with each of the methods Based on the results, the NIR band was then used to mask the contribution of water bodies by diminishing the contribution of water to urban area detection Then, manually defined visual interpretation thresholds were employed to extract the urban areas and to reduce the extent of the areas that were affected by the mixel problem (Pham and Yamaguchi, 2007) The results of this integration method were validated against the reference data sources such as land use maps published in 2002 for Hanoi and Nagoya Comparison between the results of classification, and reference data for certain sample sites was conducted visually and interpreted quantitatively The mixel problem was thus considerably reduced and the integration method provided a reliable approach for the detection of urban areas Finally, the results were classified into three categories: urban, non-urban and water (Fig 2) 3.2 Spatial metric calculations Fig Example of counting PLADJ a maximum disaggregated pattern occurs in the current class or when there are no like adjacencies, and equals 100 when the computed areas cover a single class or all adjacencies are in the same class (maximally contagious) Low PLADJ percentages imply that the extent of fragmentation is high or that there are many individual urban units on the map In order to discriminate between developed (urban) and non-developed (non-urban) pixels, a positive PLADJ value was assigned to the centre pixel if it was originally nondeveloped and conversely, a negative PLADJ value was assigned to the centre pixel if it was originally developed Secondly, to better classify the spatial heterogeneity of urban areas, a PLADJ threshold was determined This threshold was applied to the analysis of each city by visual comparison of the extent of urban fragmentation in built-up areas on the PLADJ map with it in the land use plan map or available reference data source in the same periods Finally, a pixel was considered ‘fragmented’ when its PLADJ value was less than 70%, ‘aggregated’ when its value ranged from 70% to 99%, and ‘interior’ when its value equalled 100% Fig shows an example of the PLADJ metric and illustrates the heterogeneity of urban patches in southern Hanoi The interior developed area, which appears homogeneous (yellow) in the central region, is the urban core The aggregated (developed) area connects the urban core to the suburban areas 3.2.1 The percentage like of adjacency (PLADJ) Although this study was particularly interested in the quantitative assessment of the spatial characteristics and change patterns associated with urbanization, these data cannot be extracted directly from classification results The spatial structure of urban areas in this study was therefore considered to refer to the spatial distribution of distinct urban areas on a thematic map Spatial metrics can be computed as patch-based indices (e.g size, shape, edge length, patch, density, fractal dimension) or as pixel-based indices (e.g contagion) computed for all pixels in a patch A patch refers to a homogenous region of a specific landscape property, such as a park or residential zone (Anderson et al., 1976) To measure the degree of aggregation of patch types, this study used the PLADJ metric developed by O’Neill et al (1998) to analyze the urban growth maps generated PLADJ, which is widely used because of its intuitiveness and computational simplicity (Noda and Yamaguchi, 2008), can be defined as: PLADJ = m i=1 m g i=1 ii m g k=1 ik (1) where gii is the number of like adjacencies between pixels of patch type i, gik is the number of adjacencies between pixels of patch types i and k, and m is the number of pixels in the satellite image Firstly, a × 5-pixel-moving window was used to compute the percentage of urban fragmentation for the centre cell of the window (Fig 3) PLADJ moves randomly conditional probabilities through the pixels in the moving window, with each calculation involving like adjacencies between four pixels; orthogonal cells were counted, but diagonal cells were ignored PLADJ equals zero when Fig Urban heterogeneity in southern Hanoi in 2003 calculated by PLADJ H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 227 scientific purposes, information derived solely from urban change maps does not adequately explain the forces driving urbanization and additional information is required to link the spatial structure of a city with the urban change process 3.2.2 Metric parameters In this study, six class-level spatial metrics in the FRAGSTATS spatial analysis program (McGarigal, 2002) were selected to characterize the urban composition features of a particular urban class (Table 2) Different spatial metrics in FRAGSTATS provide different information on urban growth The class area (CA) metric describes the growth of urban areas The number of urban patches (NP) measures the extent of subdivisions of urban areas NP is high when urban expansion remains constant but fragmentation increases The edge density (ED) is a measure of total length of edges of the urban patches The largest patch index (LPI) is the percentage of land occupied by a defined urban area as a function of the total urban area in a region LPI is 100 when the entire urban class consists of a single urban patch The mean nearest neighbour distance (MNN) is a measure of the open space between individual urban patches MNN is low when the distance between urban patches is high The area weighted mean patch fractal dimension (AWMPFD) is a measure of patch shape complexity If the patches are more complex and fragmented, the parameter increases to a higher fractal dimension In this study, the increase in the number of individual patches (NP) due to the expansion of the urban area was closely correlated to the increase in the length of the urban boundary (ED) The MNN measures distance between the individual urban patches and decreases if these urban patches coalesce The largest patch index (LPI) increases when urban areas become more aggregated and integrated with the urban cores Fig shows the variations in these parameters during the development of the four cities over the last 30 years (1975–2003) The original metric values of the class area (CA) and the length of the urban boundary (ED) were divided by 1000 so that they would fit on the scale of the y-axis Result and discussion Fig Urban growth pattern maps of Hanoi, Nagoya, Hartford, and Shanghai In order to visualise change patterns based on the PLADJ metric results, this study utilised the landscape transformation scheme presented by Forman (1995) Using this method, three urban growth patterns were adopted to describe and map urban sprawl: infill, expansion, and outlying The infill pattern is mostly encountered inside the existing developed areas, while the expansion pattern dominates the urban fringe The outlying pattern tends to occur some distance from the existing developed areas The result is a series of maps illustrating the changes in the urban structure of four cities from 1975 to 2003, which are discussed further in Section (Fig 5) These maps provide valuable reference information for city planners because they can be used to illustrate the historical evolution of a particular urban area However, for The urban land use plan for Shanghai was designed to transform the city from being mono-centric to a multi-centric metropolis in order to decentralize the population and economic activities (Haixiao, 2000) As reported by Haixiao, satellite towns have been planned so that the suburbs will absorb the development potential of the central city of Shanghai As can be seen in Fig 2, the satellite towns of Shanghai have had a significant impact on the progress of urban growth and urbanization in the city Based on the slight increase in the NP (Fig 6), the development of Shanghai over the period 1979–1989 was characterized by moderate growth of the urban patches While the central urban area changed slowly, there was a rapid increase in size of the satellite towns (Fig 2b4) This observation suggests that, by restricting the development of existing urban areas, the government promoted the development of metropolitan areas on the city fringe Furthermore, the mass transport lines that were constructed to link the satellite towns to the urban core from 1989 to 2001 may have been a key factor contributing to the rapid expansion of the urban areas in the region The spatial characteristics of the urban areas of Shanghai had become increasingly complex by 2001, which correlated with peak LPI and low MNN values (Fig 6) However, the peak in the AWMPFD observed in 2001 indicated an increase in the fragmentation of the urban areas, possibly due to the existence of open spaces inside the urbanized areas In addition, the dramatic increase in the LPI values implies increased development of the urban areas situated to the east of the Hangpu River (Fig 5) The new area of Pudong was also observed to expand rapidly from 1989 to 2001 (Fig 5) At the time, a large number of local inhabitants were displaced 228 H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 Table Description of the spatial metrics used in this study (McGarigal, 2002) Metric CA-Class area NP-Number of urban patches ED-Edge density LPI-Largest patch index MNN-Euclidean mean nearest neighbour distance AWMPFD-Area weighted mean patch fractal dimension Description CA equals the sum of the areas (m ) of all urban patches, divided by 10,000 (to convert to hectares) NP equals the number of urban patches in the landscape ED equals the sum of length (m) of all edge segment involving the urban patch type, divided by the total landscape area (m2 ), multiplied by 10,000 (to convert to hectares) LPI equals the area (m2 ) of the largest patch of the corresponding patch type divided by total area covered by urban land type (m2 ), multiplied by 100 (to convert to percentage) MNN equals the distance (m) mean value over all urban patches to the nearest neighbouring urban patch Area weight mean value of the fractal dimension values of all urban patches, the fractal dimension of a patch equals two times the logarithm of patch perimeter (m) divided by the logarithm of patch area (m2 ) and farmland (non-developed areas) was converted to urban use; however, the improved infrastructure and transportation improved urban living standards which contrasted with that in the central part of the city The urban structure of Hartford follows the Concentric Zone Model (Robson, 1969) The urban areas were classified to zones, such as the Central Business District (in the central part of the city), Transitional Zone, Working Class Zone, Residential Zone, and Commuter Zone The Transitional Zone includes factories, Working Class Zone includes single family tenements, Residential Zone includes single family homes, yards and garages, and the Commuter Zone consists of the suburbs As opposed to focussing on the expansion of satellite towns (as in Shanghai), urbanization in Hartford was characterized by the outlying pattern from 1975 to 1989 (Fig 5), with pronounced urban development occurring on both sides of the Connecticut River Most of this new development activity arose through the conversion of vacant land along the periphery of the city near the major transportation routes and far away from the city centre The rapid development of this outlying development pattern around the city led to an increase in the size of the urban area, which is illustrated by an increase in the both the CA and the ED The new urban areas subsequently expanded along the major transportation lines toward the city centre, such that the centre assumed a more compact shape in 1989 with LPI peaking in 2002 From 1989 onward, the rate of urbanization in Hartford started declining, which has NP value that was decreasing Although the urban growth of Hartford declined and the developed areas became more compact, outlying development occurred in the suburbs; this urban development occurring beyond the existing urban areas explains why the minimum distance between the urban patches had decreased drastically by 2002 In contrast to Shanghai and Hartford, the rate urbanization in Nagoya was moderate over time, with most urban change occurring along the urban fringe (Fig 5) In Japan, urban growth is subject to the City Planning Act which was promulgated in 1968 The Act categorises urban areas as one of two types: urbanization promotion zones, consisting of existing urban areas or areas that have already been earmarked for development in the next 10 years, and urbanization control zones, consisting of areas such as farmland where urbanization should be constrained (Saizen et al., 2006) This land use plan was expected to create a comfortable and functional urban environment while controlling suburban sprawl through the promoting the ordered development of urban areas From 1975 to 1985, the urban areas expanded on both sides of the Kiso River in the western areas of the city While urban development usually occurs through the conversion of farmland or forest to residential use, the urban development in Nagoya was restricted by the application of the City Planning Act which prohibits the conversion of Units Range Hectare CA > 0, no limit None Metres per Hectare NP ≥ 1, no limit ED ≥ 0, no limit Percent < LPI ≤ 100 Metres MNN > 0, no limit None ≤ AWMPFD ≤ agricultural land in the urbanization control zone The expansion and occurrence of outlying development in the western areas of the city resulted in the size of the urban area increasing, which was indicated by a peak in the CA in conjunction with an increase in the ED The urban growth of Nagoya started declining from 1985; instead, from 1985 to 1996, urbanization shifted to the eastern part of the city In other words, renewed urban development in Nagoya occurred in areas that were already urbanized In addition, the pattern of urban development in Nagoya created open spaces surrounded by developed urban areas The occurrence of this infill development is thought to have arisen in response to the problems caused by the patterns of urban expansion preceding 2002 The LPI peak observed in 2002 correlated with a decrease in the NP and AWMPFD, indicating that the rate of urbanization slowed down and became more homogeneous In the urban growth map (Fig 5), it can be seen that almost all of the vacant land earmarked for future development in the city of Nagoya is used, implying that the urban growth of Nagoya is likely to decrease in the future All four of the cities examined in this study have rivers flowing through their city centres Due to the marked difference in socio-economic conditions, the urbanization of Hanoi is considerably different from that observed in Hartford, Nagoya and Shanghai The land use plan in Hanoi followed the Hanoi Land Use Master Plan, which was officially promulgated in June 1998 According to the plan, urban areas will be developed in Concentric Belts, with a priority on the areas to the west, south-west, and north of the Red River by 2020 (http://www.hanoi.gov.vn/) The urban growth under the Hanoi Land Use Master Plan has been influenced by economic development We can see in Fig that before the “Doi Moi” economic reforms of 1986, there was no noticeable urban sprawl in Hanoi “Doi Moi” is the name given to the economic reforms initiated in Vietnam in 1986 for a “socialist-oriented market economy (http://en.wikipedia.org/wiki/Doi Moi) In 1975, the urban area was small and fragmented (Fig 2), which is corroborated by the small LPI and NP values (Fig 6) By 1984, the NP had increased slightly in concert with an increase in the AWMPFD, indicating that this was when Hanoi’s urban areas started to diffuse outward Since the launch of the “Doi Moi” reforms and the adoption of a market-oriented economy in 1986, the economy of the city has undergone remarkable changes, including an increase in the population of the city by approximately 500,000 people from 1984 to 1992 (Hanoi Statistical Yearbook, 2005) and an expansion of urban land use by 21,000 (Pham and Yamaguchi, 2007) Moreover, the majority of new immigrants lived in densely populated informal settlements adjacent to industrial zones, transport hubs, and major markets along the city fringes Within the context of official housing policy, these areas were considered to be illegal urban areas (Do, 2007) Fig 2b1 and c1 shows urban development in the H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 10000 Hanoi Hanoi 1000 Metric value 100 10 1975 CA 1984 NP LPI 1992 2001 ED AWMPFD 2003 MNN 10000 Nagoya 1000 Metric value 100 10 1975 CA 1985 NP LPI 1996 ED 10000 2002 AWMPFD MNN Hartford Metric value 1000 100 10 1989 1979 CA NP LPI ED 2002 AWMPFD MNN 10000 1000 Metric value Shanghai Shanghai 100 10 1979 CA NP 1989 LPI ED 2001 AWMPFD MNN Fig Fluctuation of six spatial parameters using FRAGSTATS (refer to Table for parameter descriptions) urban centres over time, the 1984 and 1992 maps show that urban expansion has occurred in two directions, one to the west and a linear branch-type to the south While expansion to the west was the predominant trend, the construction of the first national highway to the south of the city resulted in the linear expansion of the city to the south In both cases, there was an increase in the development of urbanized patches occurred some distance from the urban core; a rise in the ED and a corresponding decrease in MNN confirmed this trend At this time, the urbanization of Hanoi was also characterized by the development of urban areas along newly constructed roads and highways The area of the inner city transportation infrastructure increased from approximately 3000 in 1975 to 5000 in 1992 (Pham and Yamaguchi, 2007), implying that new road construction was a powerful catalyst for the urbanization to the west 229 and south of the city The rate of urbanization decreased after 1992 due to the economic recession in Vietnam and the 1997 economic crisis in Southeast Asia (Berg et al., 2003) Even so, despite the economic recession, approximately 700,000 immigrants moved to the city at this time Indeed, the peak observed in the value of NP in 2001 indicates a steady expansion in the size of the urban areas in Hanoi In order to promote decentralization of the city centre, numerous apartment buildings were constructed in the suburbs Taken together, 20,000 of agricultural land and water bodies areas were converted to urban use (Pham and Yamaguchi, 2007) and the urban areas continued to expand along highways to the south and south-west of the city The decline in the MNN value at this time reflected an increase in both the size and the extent of fragmentation of the urban area, and the observed peak in the AWMPFD and ED indexes in 2001 support this trend (Fig 6) Despite the observed decrease in the rate of urbanization since 2001, the urban core coalesced with the various fragmented urban patches to form a homogenous urban patch in 2003 The adoption of the “Doi Moi” reforms marked a remarkable change in the progress of urbanization in Hanoi However, compared to the cities of Hartford, Nagoya, and Shanghai, the urbanization of Hanoi has also produced several problems In the newly urbanized areas, the new transportation routes (the development zones around the city) and apartment buildings were planned very close to existing urban areas and are an average of 10 km away from the city centre This is considerably closer than the new urban areas of Hartford and Shanghai, which were located on the outskirts of existing urban areas, 20 km and 40 km from the city centre, respectively (Fig 2) The development of new urban areas far from the main city centre not only attracts people to the suburbs, but also increases the long-term development potential In Hanoi, the new urban areas were quickly assimilated into the old urban centre by the rapid and unexpected economic growth that followed the “Doi Moi” reforms Secondly, the areas of Hanoi to the east of the Red River remained relatively less developed In addition, urban growth in Hanoi has primarily occurred along the major transportation routes on the western side of the Red River, which has resulted in an increase in the price of land The resettling of inhabitants and extension of transportation routes inside the existing urban areas has also been difficult For example, in order to construct a new one-kilometre road from O Cho Dua Street to Hoang Cau Street in the Dong Da district, the government had to compensate local habitants a total of million US dollars to make space for the road (Hiep, 2009) Taken together, these problems illustrate the importance of developing adequate land use plans for Hanoi to cope with rapid urban development Conclusions The integration of remote sensing and spatial metrics provides an innovative method for analyzing urban growth patterns In this study, a detailed analysis of urban growth in Hanoi, Hartford, Nagoya, and Shanghai over a 30-year period was performed and the results were presented using urban change maps Several previous studies using remotely sensed data to detect urban change did not consider the problem of mixed pixels, resulting in the loss of spatial information However, in this study, the accuracy of urban area classification was improved by applying the classification method developed by Pham and Yamaguchi (2007) Using these results, we were able to examine the changes in the urban land use of four cities over time In 2003, the urban areas of Hanoi and Shanghai underwent considerable expansion into the suburban areas, whereas the direction of urbanization in Hartford seemed to occur from the periphery of the city toward the city centre Interestingly, the spatial characteristics of the urban areas around Nagoya varied only slightly over time 230 H.M Pham et al / Landscape and Urban Planning 100 (2011) 223–230 The results of this study show the relationship between certain changes of spatial metric parameters and a particular type of city planning Fig clearly highlights this conclusion The establishment of the urbanization control zones of Nagoya’s land use plan was reflected by slight change of spatial metrics over time On the other hand, the establishment of satellite towns around the existing city centre of Hanoi and Shanghai resulted in the border of the cities getting larger, which was demonstrated by an increase in ED and LPI The rapid development of Residential Zone in the suburb of Hartford contributed to a sudden increase in CA The land use master plans of each city are important for guiding their future urban expansion We demonstrated that the legislative instruments related to land use in urban areas have a significant affect on the patterns and nature of urbanization; this was particularly apparent in contrasting urban development scenarios in Hanoi and Nagoya In Nagoya, the existence of a well-defined master plan with its provisions for urban control and promotion zones resulted in only minor changes in the city fringe In contrast, urban development in Hanoi was less orderly, occurring mainly on the western side of the Red River and along major transportation routes As a consequence, this pattern of development resulted in the illegal conversion of vacant and agricultural land to land for urban use Improving the current land use plan and promulgating appropriate land management legislation is thus considered to be vital for the future development of Hanoi It is proposed that the methods presented in this study could be applied to the acquisition of the comprehensive 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Vietnam Econ Times., 24–25 Weber, C., 2001 Remote sensing data used for urban agglomeration delimitation Remote Sens Urban Anal., 155–167 Yamagata, Y., Sugita, S., Yasuoka, Y., 1997 Development of Vegetation-Soil-Water index algorithms and applications J Remote Sens Soc Jpn 17, 54–64  ... related to land use in urban areas have a significant affect on the patterns and nature of urbanization; this was particularly apparent in contrasting urban development scenarios in Hanoi and Nagoya... 2002) Such analyses provide quantitative characterizations of the spatial composition and configurations of habitat or land cover types, and can be used to track changes in landscape patterns over... (Henebry and Goodin, 2002) The combination of remote sensing and spatial metrics can provide spatially consistent and detailed information about urban structure and change, permitting more accurate