COHESION (class level)
Patch Cohesion Index (Aggregation metric)
lsm_c_cohesion(landscape, directions = 8)
landscape |
Raster* Layer, Stack, Brick, SpatRaster (terra), stars, or a list of rasterLayers. |
directions |
The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case). |
COHESION = 1 - (\frac{∑ \limits_{j = 1}^{n} p_{ij}} {∑ \limits_{j = 1}^{n} p_{ij} √{a_{ij}}}) * (1 - \frac{1} {√{Z}}) ^ {-1} * 100
where p_{ij} is the perimeter in meters, a_{ij} is the area in square meters and Z is the number of cells.
COHESION is an 'Aggregation metric'. It characterises the connectedness of patches belonging to class i. It can be used to asses if patches of the same class are located aggregated or rather isolated and thereby COHESION gives information about the configuration of the landscape.
Percent
0 < COHESION < 100
Approaches COHESION = 0 if patches of class i become more isolated. Increases if patches of class i become more aggregated.
tibble
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
Schumaker, N. H. 1996. Using landscape indices to predict habitat connectivity. Ecology, 77(4), 1210-1225.
lsm_c_cohesion(landscape)
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