CORE (patch level)

Core area (Core area metric)

vm_p_core(landscape, class_col = NULL, patch_col = NULL, edge_depth)

Arguments

landscape

*sf* MULTIPOLYGON or POLYGON feature

class_col

Name of the class column of the input landscape

patch_col

the name of the id column of the input landscape

edge_depth

Distance (in map units) a location has the be away from the patch edge to be considered as core location

Value

the function returns tibble with the calculated values in column "value", this function returns also some important information such as level, class, patch id and metric name.

Details

$$CORE = a_{ij}^{core}$$ where \(a_{ij}^{core}\) is the core area in square meters

CORE is a 'Core area metric' and equals the area within a patch that is not on the edge of it. A location is defined as core area if the location has no neighbour with a different value than itself. It describes patch area and shape simultaneously (more core area when the patch is large and the shape is rather compact, i.e. a square).

Units

Hectares

Range

CORE >= 0

Behaviour

Increases, without limit, as the patch area increases and the patch shape simplifies (more core area). CORE = 0 when every location in the patch is an edge.

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

Examples

vm_p_core(vector_patches, "class", "patch", edge_depth = 0.8)
#> # A tibble: 40 × 5
#>    level class id    metric     value
#>    <chr> <chr> <chr> <chr>      <dbl>
#>  1 patch 1     11    core   0.000784 
#>  2 patch 1     12    core   0.00178  
#>  3 patch 1     13    core   0.000503 
#>  4 patch 1     14    core   0        
#>  5 patch 1     15    core   0        
#>  6 patch 1     16    core   0        
#>  7 patch 1     17    core   0        
#>  8 patch 1     18    core   0.0000560
#>  9 patch 1     19    core   0        
#> 10 patch 1     20    core   0        
#> # ℹ 30 more rows