Anup,

You should have provided some additional information, such as that the
function 'hypsometric' is found in the hydroTSM contributed package.
Nevertheless, here's what I did (maybe not elegant, but it works) :

(1) at the R command prompt simply type hypsometric -- the source code for
the function 'hypsometric' will be written out
(2) copy this source code into a text file and save it as hypsometric2.R
(3) edit it as this or just copy this:

hypsometric2 <- function (x, band = 1, main = "Hypsometric Curve", xlab =
"Relative Area above Elevation, (a/A)",
    ylab = "Relative Elevation, (h/H)", col = "blue", ...)
{
    if (class(x) != "SpatialGridDataFrame")
        stop("Invalid argument: 'class(x)' must be 'SpatialGridDataFrame'")
    band.error <- FALSE
    if (is.numeric(band) | is.integer(band)) {
        if ((band < 1) | (band > length(colnames(x@data))))
            band.error <- TRUE
    }
    else if (is.character(band))
        if (!(band %in% colnames(x@data)))
            band.error <- TRUE
    if (band.error)
        stop("Invalid argument: 'band' does not exist in 'x' !")
    mydem <- x@data[band]
    z.min <- min(mydem, na.rm = TRUE)
    z.max <- max(mydem, na.rm = TRUE)
    x.dim <- x@grid@cellsize[1]
    y.dim <- x@grid@cellsize[2]
    max.area <- length(which(!is.na(mydem))) * x.dim * y.dim
    res <- plot.stepfun(ecdf(as.matrix(mydem)), lwd = 0, cex.points = 0)
    z.mean.index <- which(round(res$y, 3) == 0.5)[1]
    z.mean <- res$t[z.mean.index]
    relative.area <- (1 - res$y[-1])
    relative.elev <- (res$t[-c(1, length(res$t))] - z.min)/(z.max -
        z.min)
    plot(relative.area, relative.elev, xaxt = "n", yaxt = "n",
        main = main, xlim = c(0, 1), ylim = c(0, 1), type = "l",
        ylab = ylab, xlab = xlab, col = col, ...)
    Axis(side = 1, at = seq(0, 1, by = 0.05), labels = TRUE)
    Axis(side = 2, at = seq(0, 1, by = 0.05), labels = TRUE)
    f <- splinefun(relative.area, relative.elev, method = "monoH.FC")
    hi <- integrate(f = f, lower = 0, upper = 1)
    legend("topright", c(paste("Min Elev. :", round(z.min, 2),
        "[m.a.s.l.]", sep = " "), paste("Mean Elev.:", round(z.mean,
        1), "[m.a.s.l.]", sep = " "), paste("Max Elev. :", round(z.max,
        1), "[m.a.s.l.]", sep = " "), paste("Max Area  :",
round(max.area/1e+06,
        1), "[km2]", sep = " "), "", paste("Integral value :",
        round(hi$value, 3), sep = " "), paste("Integral error :",
        round(hi$abs.error, 3), sep = " ")), bty = "n", cex = 0.9,
        col = c("black", "black", "black"), lty = c(NULL, NULL,
            NULL, NULL))

    curve_data<-data.frame(relative.area,relative.elev)
    return(curve_data)
}

(4) rather than calling hypsometric(dem), for example, first do this:

source(hypsometric2.R)

(5) then call:

data<-hypsometric2(dem)

(6) you can see the x.y pairs by typing:

data

 at the R prompt.

(7) verify that the data are what you expect, by typing this at the R
prompt:

plot(data)

which should give the same plot as hypsometric2(dem) and hypsometric(dem)
without the embellishments and labeling...

Tom

On Fri, Apr 26, 2013 at 8:52 AM, Anup khanal <zanup@hotmail.com> wrote:

> Dear exports,I have created a hypsometric curve (area-elevation curve) for
> my watershed by using simple command hypsometric(X,main="Hypsometric
> Curve",         xlab="Relative Area above Elevation, (a/A)",
>  ylab="Relative Elevation, (h/H)", col="blue")It plots the hypsometric
> curve in "RGraphics window", My question is how can I export values which
> is used to create this plot? I mean I want to know the value in y axis for
> certain x value.
> Thanks in advance !
>
> ..................Anup KhanalNorwegian Institute of science and Technology
> (NTNU)Trondheim, NorwayMob:(+47) 45174313
>
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>
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> PLEASE do read the posting guide
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>

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