Computes Hill's index of diversity (Hill numbers) on different classes of numeric matrices using a moving window algorithm.
Hill(
x,
window = 3,
alpha = 1,
base = exp(1),
rasterOut = TRUE,
np = 1,
na.tolerance = 1,
cluster.type = "SOCK",
debugging = FALSE
)A list of matrices of dimension dim(x) with length equal to the length of alpha.
Input data may be a matrix, a Spatial Grid Data Frame, a SpatRaster, or a list of these objects. In the latter case, only the first element of the list will be considered.
The side of the square moving window. It must be an odd numeric value greater than 1 to ensure that the target pixel is in the centre of the moving window. Default value is 3.
Order of the Hill number to compute the index. If alpha is a vector with length greater than 1, then the index will be calculated over x for each value in the sequence.
The logarithm base for the calculation, default is natural logarithm.
Boolean; if TRUE, the output will be in SpatRaster format with x as the template.
The number of processes (cores) which will be spawned. Default value is 1.
A numeric value between 0.0 and 1.0, which indicates the proportion of NA values that will be tolerated to calculate Hill's index in each moving window over x. If the relative proportion of NA's in a moving window is bigger than na.tolerance, then the value of the window will be set as NA; otherwise, Hill's index will be calculated considering the non-NA values. Default value is 1.0 (i.e., full tolerance for NA's).
The type of cluster which will be created. Options are "MPI" (calls "makeMPIcluster"), "FORK," and "SOCK" (call "makeCluster"). Default type is "SOCK".
A boolean variable set to FALSE by default. If TRUE, additional messages will be printed for debugging purposes.
Hill numbers (\({}^qD\)) are calculated on numerical matrices as \({}^qD = (\sum_{i=1}^{R} {p^q}_i)^{1/(1-q)}\), where q is the order of the Hill number, R is the total number of categories (i.e., unique numerical values in a numerical matrix), and p is the relative abundance of each category. When q=1, Shannon.R is called to calculate \(exp(H^1)\) instead of the indefinite \({}^1D\). If \(q > 2*10^9\), BergerParker.R is called to calculate \(1/{{}^\infty D}\). Hill numbers of low order weight more rare categories, whereas Hill numbers of higher order weight more dominant categories.
Hill, M.O. (1973). Diversity and evenness: a unifying notation and its consequences. Ecology 54, 427-432.
BergerParker, Shannon
# Minimal example; compute Hill's index with alpha 1:5
a <- matrix(c(10,10,10,20,20,20,20,30,30),ncol=3,nrow=3)
hill <- Hill(x=a,window=3,alpha=1:5)
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