# lsm_c_iji: Interspersion and Juxtaposition index (class level) In landscapemetrics: Landscape Metrics for Categorical Map Patterns

## Description

Interspersion and Juxtaposition index (Aggregation metric)

## Usage

 1 lsm_c_iji(landscape, verbose = TRUE) 

## Arguments

 landscape Raster* Layer, Stack, Brick, SpatRaster (terra), stars, or a list of rasterLayers. verbose Print warning message if not sufficient patches are present

## Details

IJI = \frac{- ∑ \limits_{k = 1}^{m} \Bigg[ \Bigg( \frac{e_{ik}}{∑ \limits_{k = 1}^{m} e_{ik}} \Bigg) ln \Bigg( \frac{e_{ik}}{∑ \limits_{k = 1}^{m} e_{ik}} \Bigg) \Bigg]}{ln(m - 1)} * 100

where e_{ik} are the unique adjacencies of all classes (lower/upper triangle of the adjacency table - without the diagonal) 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.

Percent

0 < IJI <= 100

#### Behaviour

Approaches 0 if a class is only adjacent to a single other class and equals 100 when a class is equally adjacent to all other classes.

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

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.

lsm_l_iji
 1 lsm_c_iji(landscape)