A pre-calculated nicheR_ellipsoid object representing a hypothetical
species niche based on Annual Mean Temperature (bio_1) and Annual
Precipitation (bio_12).
Format
An object of class nicheR_ellipsoid (which is a list)
with 13 elements:
- dimensions
Integer. Number of dimensions (2).
- var_names
Character vector. Names of variables (
"bio_1","bio_12").- centroid
Named numeric vector. The center of the niche (\(\mu\)).
- cov_matrix
Matrix. The \(2 \times 2\) covariance matrix (\(\Sigma\)).
- Sigma_inv
Matrix. The precision matrix (inverse covariance).
- chol_Sigma
Matrix. Cholesky decomposition of the covariance.
- eigen
List. Eigenvectors and eigenvalues of the covariance.
- cl
Numeric. Confidence level used (e.g., 0.99).
- chi2_cutoff
Numeric. The chi-square quantile for the given
cl.- semi_axes_lengths
Numeric vector. Radii of the ellipsoid axes.
- axes_coordinates
List. Vertices (endpoints) for each ellipsoid axis.
- volume
Numeric. The hyper-volume of the ellipsoid.
- cov_limits
List. Axis-aligned minimum and maximum limits.
Details
This object serves as a template for testing community simulation functions
like conserved_ellipses. It was generated using
build_ellipsoid with a centroid at (23.75, 1750) and
specific covariance structures to reflect a typical temperature-precipitation
relationship.
Examples
data(ref_ellipse)
print(ref_ellipse)
#> nicheR Ellipsoid Object
#> -----------------------
#> Dimensions: 2D
#> Chi-square cutoff: 9.21
#> Centroid (mu): 23.5, 1750
#>
#> Covariance matrix:
#> bio_1 bio_12
#> bio_1 1.361 -100
#> bio_12 -100.000 62500
#>
#> Ellipsoid semi-axis lengths:
#> 758.715, 3.326
#>
#> Ellipsoid axis endpoints:
#> Axis 1:
#> bio_1 bio_12
#> vertex_a 24.714 991.286
#> vertex_b 22.286 2508.714
#>
#> Axis 2:
#> bio_1 bio_12
#> vertex_a 26.826 1750.005
#> vertex_b 20.174 1749.995
#>
#> Ellipsoid volume: 7927.882
#>
# Access the volume
ref_ellipse$volume
#> [1] 7927.882