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Abstract: Rapid increase of urban sprawl in many countries worldwide has become a major concern because of its detrimental effects on the environment. Existing measures of urban sprawl suffer from a confusing variety of differing, and sometimes contradictory, interpretations of the term “urban sprawl”. Therefore, results from different studies cannot usually be compared to each other and are difficult to interpret consistently. Every meaningful method to measure the degree of urban sprawl needs to be based on a clear definition of “urban sprawl” disentangling causes and consequences of urban sprawl from the phenomenon of urban sprawl itself, as urban sprawl has differing causes and consequences in different regions and regulatory contexts. This paper contributes to the development of more reliable measures of urban sprawl by providing clarifications to the definition of “urban sprawl” and by developing a set of 13 suitability criteria for measures of urban sprawl. Our study proceeds in three steps. First, it proposes a clear definition of urban sprawl that is based on an evaluation of existing urban sprawl definitions. Second, it derives from this definition 13 suitability criteria for measures of urban sprawl. These criteria are useful to systematically evaluate the consistency and reliability of existing and future metrics of urban sprawl. The 13 criteria include (1) intuitive interpretation, (2) mathematical simplicity, (3) modest data requirements, (4) low sensitivity to very small patches of urban area, (5) monotonous response to increases in urban area, (6) monotonous response to increasing distance between two urban patches when within the scale of analysis, (7) monotonous response to increased spreading of three urban patches, (8) same direction of the metric''s responses to the processes in criteria 5, 6 and 7, (9) continuous response to the merging of two urban patches, (10) independence of the metric from the location of the pattern of urban patches within the reporting unit, (11) continuous response to increasing distance between two urban patches when they move beyond the scale of analysis, (12) mathematical homogeneity (i.e., intensive or extensive measure), and (13) additivity (i.e., additive or area-proportionately additive measure). Third, we illustrate the application of the 13 criteria by systematically assessing three existing measures of urban sprawl. We conclude that suitability criteria help understand the behavior of metrics intended to measure urban sprawl and to identify the most suitable measures. This article is the first part of a set of two papers. [Copyright &y& Elsevier]

Abstract: Urban sprawl (dispersed urban development) has increased at alarming rates in Europe and North America over the last 50 years. Quantitative data are urgently needed in monitoring systems for sustainable development. However, there is a lack of reliable measures of urban sprawl that take into account the spatial configuration of the urban areas (not just total amount). This paper introduces four new measures of urban sprawl: degree of urban dispersion (DIS), total sprawl (TS), degree of urban permeation of the landscape (UP), and sprawl per capita (SPC). They characterize urban sprawl from a geometric point of view. The measures are related through TS = DIS ×urban area, UP = TS/size of the landscape studied, and SPC = TS/number of inhabitants. The paper investigates the properties of the new measures systematically using 13 suitability criteria which were derived from a clear definition of urban sprawl as discussed in a previous paper. The scale of analysis is specified by the so-called horizon of perception. Second, the new measures are applied to three examples from Switzerland. Subsequently, the measures are briefly compared to other measures of urban sprawl from the literature. We demonstrate that UP is an intensive and area-proportionately additive measure and is suitable for comparing urban sprawl among regions of differing size, while SPC is most appropriate when comparing sprawl in relation to human population density. The paper also provides practical advice for calculating the new measures. We conclude that the new method is more suitable than previous methods to quantify the indicator “urban sprawl” in monitoring systems as this method distinguishes the phenomenon of urban sprawl from its various causes and consequences. This article is part II of a set of two papers. [Copyright &y& Elsevier]