PARA_MN (class level)
Mean perimeter-area ratio (Shape metric)
lsm_c_para_mn(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). |
PARA_{MN} = mean(PARA[patch_{ij}]
where PARA[patch_{ij}] is the perimeter area ratio of each patch.
PARA_MN is a 'Shape metric'. It summarises each class as the mean of each patch belonging to class i. The perimeter-area ratio describes the patch complexity in a straightforward way. However, because it is not standarised to a certain shape (e.g. a square), it is not scale independent, meaning that increasing the patch size while not changing the patch form will change the ratio.
None
PARA_MN > 0
Approaches PARA_MN > 0 if PARA for each patch approaches PARA > 0, i.e. the form approaches a rather small square. Increases, without limit, as PARA increases, i.e. patches become more complex.
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
lsm_c_para_mn(landscape)
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