Total (class) edge (Area and Edge metric)

## Arguments

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

- count_boundary
Include landscape boundary in edge length

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

## Details

$$TE = \sum \limits_{k = 1}^{m} e_{ik}$$
where \(e_{ik}\) is the edge lengths in meters.
TE is an 'Area and edge metric'. Total (class) edge includes all edges between class i and
all other classes k. It measures the configuration of the landscape because a highly
fragmented landscape will have many edges. However, total edge is an absolute measure,
making comparisons among landscapes with different total areas difficult. If
`count_boundary = TRUE`

also edges to the landscape boundary are included.

## References

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