Standard deviation of Contiguity index (Shape metric)
lsm_l_contig_sd(landscape, directions = 8)tibble
A categorical raster object: SpatRaster; Raster* Layer, Stack, Brick; stars or a list of SpatRasters.
The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).
$$CONTIG_{SD} = sd(CONTIG[patch_{ij}])$$
where \(CONTIG[patch_{ij}]\) is the contiguity of each patch.
CONTIG_SD is a 'Shape metric'. It summarises the landscape as the standard deviation of all patches in the landscape. CONTIG_SD asses the spatial connectedness (contiguity) of cells in patches. The metric coerces patch values to a value of 1 and the background to NA. A nine cell focal filter matrix:
filter_matrix <- matrix(c(1, 2, 1,
2, 1, 2,
1, 2, 1), 3, 3, byrow = TRUE)
... is then used to weight orthogonally contiguous pixels more heavily than diagonally contiguous pixels. Therefore, larger and more connections between patch cells in the rookie case result in larger contiguity index values.
None
CONTIG_SD >= 0
CONTIG_SD = 0 if the contiguity index is identical for all patches. Increases, without limit, as the variation of CONTIG increases.
McGarigal K., SA Cushman, and E Ene. 2023. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical Maps. Computer software program produced by the authors; available at the following web site: https://www.fragstats.org
LaGro, J. 1991. Assessing patch shape in landscape mosaics. Photogrammetric Engineering and Remote Sensing, 57(3), 285-293
lsm_p_contig,
lsm_c_contig_sd,
lsm_c_contig_cv,
lsm_c_contig_mn,
lsm_l_contig_cv,
lsm_l_contig_mn
landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_contig_sd(landscape)
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