lsm_l_contag: CONTAG (landscape level)

Description Usage Arguments Details Value References Examples

Description

Contagion (Aggregation metric)

Usage

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lsm_l_contag(landscape, verbose)

## S3 method for class 'RasterLayer'
lsm_l_contag(landscape, verbose = TRUE)

## S3 method for class 'RasterStack'
lsm_l_contag(landscape, verbose = TRUE)

## S3 method for class 'RasterBrick'
lsm_l_contag(landscape, verbose = TRUE)

## S3 method for class 'stars'
lsm_l_contag(landscape, verbose = TRUE)

## S3 method for class 'list'
lsm_l_contag(landscape, verbose = TRUE)

Arguments

landscape

Raster* Layer, Stack, Brick or a list of rasterLayers.

verbose

Print warning message if not sufficient patches are present

Details

CONTAG = 1 + \frac{∑ \limits_{q = 1}^{n_{a}} p_{q} ln(p_{q})}{2ln(t)}

where p_{q} the adjacency table for all classes divided by the sum of that table and t the number of classes in the landscape.

CONTAG is an 'Aggregation metric'. It is based on cell adjacencies and describes the probability of two random cells belonging to the same class. p_{q} is the cell adjacency table, where the order is preserved and pairs of adjacent cells are counted twice. Contagion is affected by both the dispersion and interspersion of classes. E.g., low class dispersion (= high proportion of like adjacencies) and low interspersion (= uneven distribution of pairwise adjacencies) lead to a high contagion value.

The number of classes to calculate CONTAG must be >= than 2.

Units

Percent

Range

0 < Contag <=100

Behaviour

Approaches CONTAG = 0 if all cells are unevenly distributed and 100 indicates that all cells are equally adjacent to all other classes.

Value

tibble

References

McGarigal, K., SA Cushman, and E Ene. 2012. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical and Continuous Maps. Computer software program produced by the authors at the University of Massachusetts, Amherst. Available at the following web site: http://www.umass.edu/landeco/research/fragstats/fragstats.html

Riitters, K.H., O’Neill, R.V., Wickham, J.D. & Jones, K.B. (1996). A note on contagion indices for landscape analysis. Landscape ecology, 11, 197–202.

Examples

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r-spatialecology/landscapemetrics documentation built on May 20, 2019, noon