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A distance dependent contagion function for vector-based data

Ramezani , Habib and Holm, Sören (2011). A distance dependent contagion function for vector-based data. Environmental and ecological statistics. online , 1-24
[Research article]

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Official URL: http://dx.doi.org/10.1007/s10651-011-0180-1


Landscape pattern is of primary interest to landscape ecologists and landscape metrics are used to quantify landscape pattern. Metrics are commonly defined and calculated on raster-based land cover maps. One metric is the contagion, existing in several versions, e.g., unconditional and conditional, used as a measure of fragmentation. However, mapped data is sometimes in vector-based format or there may be no mapped data but only a point sample. In this study a definition of contagion for such cases is investigated. The metric is an extension of the usual contagion, based on pairs of points at varying distances and gives a function of the distance. In this study the extended contagion is calculated for vector-based delineated real landscapes and for simulated ones. Both unconditional and conditional contagions are studied using two classification systems. The unconditional contagion function was decreasing and convex, with upper and lower limits highly correlated to the Shannon diversity index, thus carrying only area proportion information. The spatial information lies in the speed by which the function converges to the lower limit; using a proxy function this can be expressed by a single parameter b, with high values for fragmented landscapes. No proxy function was found for the conditional contagion, for which only qualitative information was found. The extended contagion is applicable both in patch mosaic models of landscapes and in gradient-based models, where landscape characteristics change continuously without distinct borders between patches. The extended contagion can be useful in sample based surveys where there no map of the entire landscape is available.

Authors/Creators:Ramezani , Habib and Holm, Sören
Title:A distance dependent contagion function for vector-based data
Series Name/Journal:Environmental and ecological statistics
Year of publishing :2011
Page range:1-24
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Accepted version
Full Text Status:Public
Subjects:Obsolete subject words > FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING > Landscape planning > Nature conservation and landscape management
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 207 Environmental Engineering > Remote Sensing
Keywords:Landscape pattern analysis, contagion, vector-based
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Type of IDID
ID Code:8449
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
Deposited By: Dr Habib Ramezani
Deposited On:07 Dec 2011 10:30
Metadata Last Modified:02 Dec 2014 10:48

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