R/gx.ecdf.R

In rgr: Applied Geochemistry EDA

gx.ecdf <-
function (xx, xlab = deparse(substitute(xx)), ylab = "Empirical Cumulative Distribution Function", 
    log = FALSE, xlim = NULL, main = "", pch = 3, ifqs = FALSE, 
    cex = 0.8, ...) 
{
    temp.x <- remove.na(xx)
    x <- sort(temp.x$x[1:temp.x$n])
    nx <- temp.x$n
    y <- ((1:nx) - 0.5)/nx
    if (log) {
        logx <- "x"
        if ((!is.null(xlim)) && (xlim[1] <= 0)) 
            xlim[1] <- min(x)
    }
    else logx <- ""
    if (is.null(xlim)) {
        plot(x, y, log = logx, xlab = xlab, ylab = ylab, main = main, 
            pch = pch, las = 1, ...)
        limits <- par("usr")
        nxx <- nx
    }
    else {
        xt <- x[(x >= xlim[1]) & (x <= xlim[2])]
        yt <- y[(x >= xlim[1]) & (x <= xlim[2])]
        plot(xt, yt, log = logx, xlim = xlim, xlab = xlab, ylab = ylab, 
            main = main, pch = pch, las = 1, ...)
        limits <- par("usr")
        nxx <- length(xt)
    }
    if (ifqs) {
        abline(h = 1:3/4, lty = 3)
        abline(v = quantile(x, probs = c(0.25, 0.5, 0.75)), lty = 3)
    }
    xpos <- limits[2] - (limits[2] - limits[1]) * 0.05
    ypos <- limits[3] + (limits[4] - limits[3]) * 0.11
    if (log) 
        xpos <- 10^xpos
    text(xpos, ypos, labels = paste("N =", nx), adj = 1, cex = cex)
    if (nxx != nx) {
        ypos <- limits[3] + (limits[4] - limits[3]) * 0.05
        text(xpos, ypos, labels = paste(nx - nxx, "points omitted"), 
            adj = 1, cex = cex * 0.8)
    }
    invisible()
}