R help - Dec 2003 - contour() should handle the asp parameter

Hi all,

To my knowledge, the current version of contour.default() does not handle the
'asp' parameter. This can be embarassing when displaying eg geographical
maps, etc... Submitted to the opinion of more experienced R programmers,
contour.defaut() function should be changed according to the followings:

line 7: add = FALSE,asp=NA,...)
line 33: plot.window(xlim, ylim, asp=asp,"")

The new script would be:

contour.default<-
function (x = seq(0, 1, len = nrow(z)), y = seq(0, 1,
len = ncol(z)),z, nlevels = 10, levels = pretty(zlim, nlevels), labels = NULL,
xlim = range(x, finite = TRUE), ylim = range(y, finite = TRUE),
    zlim = range(z, finite = TRUE), labcex = 0.6, drawlabels = TRUE,
    method = "flattest", vfont = c("sans serif",
"plain"), axes = TRUE,
    frame.plot = axes, col = par("fg"), lty = par("lty"),
lwd = par("lwd"),
    add = FALSE,asp=NA,...)
{
    if (missing(z)) {
        if (!missing(x)) {
            if (is.list(x)) {
                z <- x$z
                y <- x$y
                x <- x$x
            }
            else {
                z <- x
                x <- seq(0, 1, len = nrow(z))
            }
        }
        else stop("no `z' matrix specified")
    }
    else if (is.list(x)) {
        y <- x$y
        x <- x$x
    }
    if (any(diff(x) <= 0) || any(diff(y) <= 0))
        stop("increasing x and y values expected")
    if (!is.matrix(z) || nrow(z) <= 1 || ncol(z) <= 1)
        stop("no proper `z' matrix specified")
    if (!add) {
        plot.new()
        plot.window(xlim, ylim, asp=asp,"")
        title(...)
    }
    if (!is.double(z))
        storage.mode(z) <- "double"
    method <- pmatch(method[1], c("simple", "edge",
"flattest"))
    if (!is.null(vfont))
        vfont <- c(typeface = pmatch(vfont[1], Hershey$typeface) -
            1, fontindex = pmatch(vfont[2], Hershey$fontindex))
    if (!is.null(labels))
        labels <- as.character(labels)
    .Internal(contour(as.double(x), as.double(y), z, as.double(levels),
        labels, labcex, drawlabels, method, vfont, col = col,
        lty = lty, lwd = lwd))
    if (!add) {
        if (axes) {
            axis(1)
            axis(2)
        }
        if (frame.plot)
            box()
    }
    invisible()
}
<environment: namespace:base>




Best regards,

Patrick
	[[alternative HTML version deleted]]

Given contour() has an add= argument whose use is demonstrated for this 
exact reason in `all good books on S', why complicate the contour 
function?

Contrary to popular belief, the `asp parameter' is not a parameter, but an 
argument of plot's default method.

On Sun, 14 Dec 2003, Patrick Giraudoux wrote:
> To my knowledge, the current version of contour.default() does not handle
the 'asp' parameter. This can be embarassing when displaying eg
geographical maps, etc... Submitted to the opinion of more experienced R
programmers, contour.defaut() function should be changed according to the
followings:
> 
> line 7: add = FALSE,asp=NA,...)
> line 33: plot.window(xlim, ylim, asp=asp,"")
And of course alter the documentation.

I suspect you could get away with passing ... to the plot.window call, 
which for clarity should be plot.window(xlim, ylim, "", asp = asp)

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595