R/ordicenter.R

In zdealveindy/ordijuice: Unconstrained ordinations of vegetation data in JUICE program

ordicenter <-
function (ord, groups, display = "sites", w = weights(ord, display), 
    show.groups, ...) 
{
    weights.default <- function(object, ...) NULL
    pts <- scores(ord, display = display, ...)
    w <- eval(w)
    if (length(w) == 1) 
        w <- rep(1, nrow(pts))
    if (is.null(w)) 
        w <- rep(1, nrow(pts))
    if (!missing(show.groups)) 
        {
        take <- groups %in% show.groups
        pts <- pts[take, , drop = FALSE]
        groups <- groups[take]
        w <- w[take]
        }
    out <- seq(along = groups)
    inds <- names(table(groups))
    for (is in inds) 
      {
        gr <- out[groups == is]
        if (length(gr) > 1)
         {
            X <- pts[gr, ]
            W <- w[gr]
            ave <- apply(X, 2, weighted.mean, w = W)
            ordiArgAbsorber(ave[1], ave[2], labels = is, FUN = text, cex = 1.2, ...)
        }
        if (length(gr) == 1)
         {
            X <- pts[gr, ]
            W <- w[gr]
            ordiArgAbsorber(X[1], X[2], labels = is, FUN = text, cex = 1.2, ...)
        }
    }
    invisible()
}