Interspersion and Juxtaposition index (Aggregation metric)
lsm_l_iji(landscape, verbose)# S3 method for RasterLayer
lsm_l_iji(landscape, verbose = TRUE)
# S3 method for RasterStack
lsm_l_iji(landscape, verbose = TRUE)
# S3 method for RasterBrick
lsm_l_iji(landscape, verbose = TRUE)
# S3 method for stars
lsm_l_iji(landscape, verbose = TRUE)
# S3 method for list
lsm_l_iji(landscape, verbose = TRUE)
Raster* Layer, Stack, Brick or a list of rasterLayers.
Print warning message if not sufficient patches are present
tibble
$$IJI = \frac{- \sum \limits_{i = 1}^{m} \sum \limits_{k = i + 1}^{m} \Bigg[ \Bigg( \frac{e_{ik}}{E} \Bigg) ln \Bigg( \frac{e_{ik}}{E} \Bigg) \Bigg]}{ln(0.5[m(m - 1)])} * 100$$
where \(e_{ik}\) are the unique adjacencies of all classes (lower/upper triangle of the adjacency table - without the diagonal), \(E\) is the total length of edges in the landscape and \(m\) is the number of classes.
IJI is an 'Aggregation metric'. It is a so called "salt and pepper" metric and describes the intermixing of classes (i.e. without considering like adjacencies - the diagonal of the adjacency table). The number of classes to calculate IJI must be >= than 3.
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
McGarigal, K., & Marks, B. J. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. Gen. Tech. Rep. PNW-GTR-351. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station. 122 p, 351.
# NOT RUN {
lsm_l_iji(landscape)
# }
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