Simulating Block-Level Urban Expansion for National Wide Cities

Abstract

Abstract:Large-scale models are generally associated with large spatial modelling units, for example, counties or super grids (several to dozens of km 2 ). Few applied urban models can achieve a large spatial coverage with irregular spatial units due to data availability and computation load. The framework of automatic identification and characterization of blocks developed by Liu and Long (2016) makes such an ideal model possible by establishing the existing urban blocks using road networks and points of interest for very large areas (e.g., a country or a continent). In this study, we develop a mega-vector-blocks cellular automata model (MVB-CA) to simulate urban expansion at the block level for 654 Chinese cities. The existing urban blocks in 2012 were used for initiating the MVB-CA and are generated using multi-levelled road networks and ubiquitous points of interest. We then simulate block-based urban expansion of all the cities from 2012 to 2017. The national spatial development strategies of China are discussed extensively by academia and policy makers, while the baseline scenario and other simulated urban expansion scenarios have been tested and compared horizontally. As one of the first block-based urban expansion models at a national scale, its academic contributions, practical applications, and potential biases are also discussed in this paper. The developed MVB-CA using general approaches is also applicable for other counties.

Transit-oriented development: Literature review and evaluation of TOD potential across 50 Chinese cities

“…To evaluate urban expansions and TOD effects in each transit metropolis in more quantitative detail, we propose some additional indicators: Urban Land Parcel's Size (ULPS, e.g., Built areas), Expanded Land Parcel's Size (ELPS), Expanded Land Parcels Size Ratio (ExR = ELPS/ULPS), TOD Parcel's Size (TODPS), TOD Parcel's Ratios (TODR= TODPS/ULPS) and a ratio of TOD parcels to expand land parcels (TOD/Ex = TODR/ExR). ULPS denotes the built areas of each transit metropolis in 2020; ELPS denotes the expanded urban areas during 2015 and 2020 according to each metropolis's recent land-use planning under the NTU scenario (Liu & Long, 2016;Long & Wu, 2017); and ExR demonstrates the ratio of the expanded urban areas to the total urban built areas in 2020; TODPS represents the expanded urban land areas close to metro stations in each transit metropolis, and TODR denotes the percentage of TODPS relative to the total urban built area; finally, TOD/Ex is used to demonstrate the ratio of urban land areas expanded due to TOD practices to the total expanded urban land areas. TOD/Ex offers a direct measure of TOD effects on urban expansion.…”

“…The geographic location of rail transit stations was collected from the database on China City Metro Website (http://www.ccmetro.com/). In this case, the methodology of future urban land use simulation could be referred in (Liu & Long, 2016;Long & Wu, 2017). We refer to converted parcels as "TOD parcels" in this paper.…”

Understanding urban China with open data

“…2; Wu, Long, Mao, & Liu, 2015). Along the same lines, we have produced block-boundaries for all Chinese cities, identified urban blocks based on their functionalities, and simulated urban growth for five year periods at the block level (Long, Wu, & Mao, 2014). These datasets substantively improve the basic spatial units for further exploration of Chinese cities, as cities are now being measured on a unit that corresponds to the spatial extent of daily routines, i.e., the urban block, rather than the conventionally used regular grids that bear little resemblance to urban functional areas (Long & Liu, 2013).…”

Simulating Uneven Urban Spatial Expansion under Various Land Protection Strategies: Case Study on Southern Jiangsu Urban Agglomeration

“…Accordingly, USE has long been a main target for governmental concerns and scholarly attention [6]. Early studies mostly focused on individual cities and their processes, models, influencing factors, and effects (e.g., [7][8][9]). However, as more issues are caused (and resolved) in regions composed by a group of cities, the uneven USE has received increasing research attention in recent years [10,11].…”

“…The uneven occurrence is explained by different theories and affected by various factors, which are expressed by both the different extant size and expanding speed of the cities. As for the foundational support of industries and population, urban spatial expansion is primarily driven by regional industrial development and population growth; hence their differences would bring different needs for urban space, and therefore, dissimilar urban expansion [7,12]. The theory of the urban growth machine explores how economic and population growth affects patterns of urbanization, and indicates the effects of different factors [13].…”