lsm_c_cai_sd | R Documentation |

Standard deviation of core area index (Core area metric)

```
lsm_c_cai_sd(
landscape,
directions = 8,
consider_boundary = FALSE,
edge_depth = 1
)
```

`landscape` |
A categorical raster object: SpatRaster; Raster* Layer, Stack, Brick; stars or a list of SpatRasters. |

`directions` |
The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case). |

`consider_boundary` |
Logical if cells that only neighbour the landscape boundary should be considered as core |

`edge_depth` |
Distance (in cells) a cell has the be away from the patch edge to be considered as core cell |

`CAI_{SD} = sd(CAI[patch_{ij}]`

where `CAI[patch_{ij}]`

is the core area index of each patch.

CAI_SD is a 'Core area metric'. The metric summarises each class as the standard deviation of the core area index of all patches belonging to class i. The core area index is the percentage of core area in relation to patch area. A cell is defined as core area if the cell has no neighbour with a different value than itself (rook's case). The metric describes the differences among patches of the same class i in the landscape.

Because the metric is based on distances or areas please make sure your data
is valid using `check_landscape`

.

Percent

CAI_SD >= 0

Equals CAI_SD = 0 if the core area index is identical for all patches. Increases, without limit, as the variation of core area indices increases.

tibble

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

`lsm_p_cai`

,
`sd`

`lsm_c_cai_mn`

,
`lsm_c_cai_cv`

,

`lsm_l_cai_mn`

,
`lsm_l_cai_sd`

,
`lsm_l_cai_cv`

```
landscape <- terra::rast(landscapemetrics::landscape)
lsm_c_cai_sd(landscape)
```

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