Measuring Spatial Concentration: The Use of Threshold Profiles

2003 ◽  
Vol 30 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Ron Johnston ◽  
David Voas
Keyword(s):  
Spatial Pattern ◽  
Spatial Scale ◽  
Concentration Profile ◽  
Gini Coefficient ◽  
Reference Group ◽  
Public Policies ◽  
Spatial Concentration ◽  
England And Wales ◽  
Alternative Approach ◽  
Single Number

The measurement of spatial pattern is often undertaken using one of a number of single-number indices, such as the Gini coefficient, which may not illuminate certain aspects of the pattern involved—especially the degree to which the members of the reference group are spatially concentrated. We suggest an alternative approach based on a concentration profile which shows the degree to which a group is spatially concentrated according to a range of thresholds. This is illustrated with data on male unemployment in England and Wales in 1991, which also shows the importance of spatial scale to the study of concentrations and, potentially, to the formulation of spatially focused public policies.

scholarly journals Forest birds respond to the spatial pattern of exurban development in the Mid-Atlantic region, USA

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2039 ◽  
Author(s):  
Marcela Suarez-Rubio ◽  
Todd R. Lookingbill
Keyword(s):  
Spatial Pattern ◽  
Spatial Scale ◽  
Forest Fragmentation ◽  
Spatial Scales ◽  
The United States ◽  
Forest Edge ◽  
Forest Birds ◽  
Bird Diversity ◽  
Forest Loss ◽  
Exurban Development

Housing development beyond the urban fringe (i.e., exurban development) is one of the fastest growing forms of land-use change in the United States. Exurban development’s attraction to natural and recreational amenities has raised concerns for conservation and represents a potential threat to wildlife. Although forest-dependent species have been found particularly sensitive to low housing densities, it is unclear how the spatial distribution of houses affects forest birds. The aim of this study was to assess forest bird responses to changes in the spatial pattern of exurban development and also to examine species responses when forest loss and forest fragmentation were considered. We evaluated landscape composition around North American Breeding Bird Survey stops between 1986 and 2009 by developing a compactness index to assess changes in the spatial pattern of exurban development over time. Compactness was defined as a measure of how clustered exurban development was in the area surrounding each survey stop at each time period considered. We used Threshold Indicator Taxa Analysis to detect the response of forest and forest-edge species in terms of occurrence and relative abundance along the compactness gradient at two spatial scales (400-m and 1-km radius buffer). Our results showed that most forest birds and some forest-edge species were positively associated with high levels of compactness at the larger spatial scale; the proportion of forest in the surrounding landscape also had a significant effect when forest loss and forest fragmentation were accounted for. In contrast, the spatial configuration of exurban development was an important predictor of occurrence and abundance for only a few species at the smaller spatial scale. The positive response of forest birds to compactness at the larger scale could represent a systematic trajectory of decline and could be highly detrimental to bird diversity if exurban growth continues and creates more compacted development.

Study on Intercity Differences of Chinese Urban Economic Efficiency and its Spatial - Temporal Characteristics: Base on 273 Cities at Prefecture Level or above in China

2014 ◽  
Vol 962-965 ◽  
pp. 2185-2190
Author(s):  
Ga Rang Zhuoma ◽  
Ci Fang Wu
Keyword(s):  
Spatial Pattern ◽  
Economic Efficiency ◽  
High Efficiency ◽  
Spatial Concentration ◽  
Temporal Characteristics ◽  
Urban Economic

This paper measures the urban economic efficiency using the three-stage DEA and analyzes the differences and temporal characteristics of the intercity, based on the data from 273 Cities at Prefecture level or above in China during the period 2002 - 2011. The results indicate that : (1) Urban economic efficiency three-stage DEA estimated was significantly lower than the general DEA, indicating that environmental and random factors have a great impact on urban economic efficiency in China; (2) China's urban economic efficiency intercity difference is very significant, "Bei-Shang-Guang" Metropolitan is a major frontier; (3) Urban economic efficiency intercity difference spatial pattern is very stable, spatial concentration areas of the high efficiency and the low ​​in the study little changed.

scholarly journals SEDIMENT- AND MORPHODYNAMICS OF SHOREFACE NOURISHMENTS ALONG THE NORTH-HOLLAND COAST

2012 ◽  
Vol 1 (33) ◽  
pp. 44 ◽  
Author(s):  
Ben De Sonneville ◽  
Ad Van der Spek
Keyword(s):  
Spatial Scale ◽  
Temporal Scale ◽  
Maintenance Policy ◽  
The North ◽  
Alternative Approach ◽  
Erosion Hotspots ◽  
Coastal Maintenance

The Dutch coastal maintenance policy which was implemented in 1990 aims at fighting structural erosion by nourishing sand. Initially, the beaches were nourished. The lifetime of these beach nourishments turned out to be relatively short (~2 yrs), especially at identified erosion ‘hotspots’ along the North-Holland coast (e.g. Egmond aan Zee). Therefore, from 1999 on, an alternative approach was considered, in which beach nourishments were combined with large nourishments on the shoreface (seaward of the outer breaker bar). In recent years, the evolution of individual shoreface nourishments was analyzed on a spatial scale of kilometres and a temporal scale of years, with a focus on their cross-shore development (e.g., Van Duin et al., 2004). In these studies, their alongshore interaction received little attention. The main objective of the present study is to investigate the evolution and lifetime of five large (~1-2 million m3) shoreface nourishments applied between 1999 and 2005 on a spatial scale that includes the larger part of the North-Holland coast (~40km). The analysis of bathymetrical data shows that all five shoreface nourishments evolved into new outer bars with deep troughs on their landward side, that temporarily interrupted the ‘autonomous’ cyclic offshore migration of breaker bars (e.g. Wijnberg, 1995). Alongshore, the nourishment placed at Camperduin in 2002 connected to the existing outer bar, while the nourishments placed at Egmond aan Zee and Bergen in 1999 and 2000 respectively, remained isolated. The 2004 Egmond and 2005 Bergen nourishments interconnected into a long bar. At Camperduin, the newly formed outer bar remained quite stable in the years after its placement. The bars resulting from the 1999 Egmond aan Zee and 2000 Bergen nourishments, however, almost fully disintegrated within five years, while the interconnected bar of the 2004 and 2005 nourishments is still largely intact after 5 years. The results suggest that the effectiveness of shoreface nourishments is influenced by their shore-parallel length and their ability to connect to surrounding (natural or nourishment) bars. The observed morphodynamic patterns suggest that the ‘lost’ sand is mainly redistributed to the breaker zone, and further transported alongshore.

A Behavioural Approach to Retail Blight

1983 ◽  
Vol 15 (6) ◽  
pp. 739-750 ◽  
Author(s):  
M Marcus
Keyword(s):  
England And Wales ◽  
Behavioural Approach ◽  
Alternative Approach ◽  
Considerable Confusion ◽  
Vacancy Rates ◽  
Retail Structure ◽  
Retail Activity

This paper examines one type of decline referred to as retail ‘blight’. It is argued that retail blight is most frequently defined in terms of undesirable structural phenomena, such as high vacancy rates, and that this has led to considerable confusion. A case is made for an alternative approach, that is, to define retail blight as a deviant behavioural process which may eventually result in loss of retail activity; undesirable changes in retail structure are viewed as symptoms of this process. This alternative approach is explained in relation to blighted shopping precincts in England and Wales.

Spatial patterns in taiga plant communities following fire

1993 ◽  
Vol 71 (12) ◽  
pp. 1568-1573 ◽  
Author(s):  
James A. Schaefer
Keyword(s):  
Spatial Pattern ◽  
Key Words ◽  
Spatial Scale ◽  
Plant Communities ◽  
Spatial Patterns ◽  
Single Species ◽  
Stand Age ◽  
Individual Species ◽  
Age Classes ◽  
Postfire Succession

The scales of spatial patterns of the vascular understorey were examined during postfire succession in the taiga of southeastern Manitoba. Patterns of individual species from analogous burned (5 years old) and old-growth (≥ 90 years old) communities were revealed using Paired Quadrat Variance; multispecies patterns were determined with Moran's I following ordination. The scales of single-species patterns were variable within communities and not significantly different between the two age classes. Similarly, multispecies patterns displayed no consistent differences in scale according to age of the community. The results fail to support the hypothesis that the scale of the spatial pattern in plant communities increases with stand age. Key words: fire, taiga, spatial scale, succession.

Impacts of Absolute and Relative Income on Self-Rated Health in Urban and Rural China

2020 ◽  
pp. 002073142092268
Author(s):  
Jiaoli Cai ◽  
Audrey Laporte ◽  
Li Zhang ◽  
Yulin Zhao ◽  
Di Tang ◽  
...  
Keyword(s):  
Gini Coefficient ◽  
Urban Population ◽  
Dynamic Models ◽  
Reference Group ◽  
Rural China ◽  
Relative Income ◽  
Urban China ◽  
Nutrition Survey ◽  
Self Rated Health ◽  
The Gini Coefficient

This study aims to assess the impacts of absolute and relative income on self-rated health (SRH) of residents in rural and urban China. Data were derived from the China Health and Nutrition Survey. Three distinct measures of relative income were considered (Gini coefficient, Yitzhaki index, and Deaton index) and computed for 3 geographic units (nation, province, and community). Nonlinear dynamic models for panel data were employed to test the absolute and relative income hypotheses. Absolute income was significantly associated with SRH among urban and rural populations. Relative income, as measured by the Gini coefficient, the Yitzhaki index, and the Deaton index, had statistically significant and negative impacts on SRH among the rural population, regardless of the reference group. For the urban population, the Gini coefficient was associated with SRH regardless of the reference group. In contrast, only the Yitzhaki index and the Deaton index at the provincial level were associated with SRH among the urban population. Our findings may provide a reference for policymakers to implement health policies designed to improve population health.

scholarly journals Interactions between fish and fisher's spatial distribution and behaviour: an empirical study of the anchovy (Engraulis ringens) fishery of Peru

2004 ◽  
Vol 61 (7) ◽  
pp. 1127-1136 ◽  
Author(s):  
Sophie Bertrand ◽  
Erich Díaz ◽  
Miguel Ñiquen
Keyword(s):  
Spatial Scale ◽  
Spatial Dynamics ◽  
Fishing Ground ◽  
Fish Stock ◽  
Commercial Fishing ◽  
Spatial Concentration ◽  
Time Period ◽  
Engraulis Ringens ◽  
Spatio Temporal ◽  
Potential Interactions

Abstract Fishing data provide, with wide spatio-temporal coverage, inexpensive information about exploited species, but a precondition for their interpretation is a good comprehension of fish and fisher spatial dynamics and interactions. In Peru, anchovy (Engraulis ringens) is exploited by an industrial fleet of about 800 purse-seiners operating all along the coast. Using simultaneous acoustic survey and commercial fishing data for the 1998–2001 time period, we present a preliminary, exploratory, and empirical approach to identify the nature of potential interactions between Peruvian anchovy and fisher behaviour. We show that (i) Peruvian anchovy exhibited a composite spatial strategy for the study period, i.e. a change in biomass was associated with both change in geographical extension and density; (ii) fishing behaviour significantly varied within and among vessels in terms of travel duration, searching duration, and number of fishing sets; and (iii) interactions between fish and fisher behaviours differed according to the spatial scale. At a fish stock scale (the scale of fishing ground selection for fishers), fishing was more efficient with low biomass and high spatial concentration (low stock range and high biomass); at a local fish spatial scale (the scale of searching for a school inside the fishing ground), fishing performance was favoured by high mean local abundances and low spatial concentration (the way fish is distributed inside its stock range); finally, at the school scale (the scale of the fishing set), both high abundance and high spatial concentration were favourable to fishing success.

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