R help - Jun 2008 - in axis() suppressing axis line but keeping tick marks

I've been trying to figure out a parameter that will let you separately
adjust the parameters for the axis line from the tick mark.

In the following example, I would like to suppress the axis line, but keep
the tick marks.

Thanks,
Andrew


foo <- data.frame(x=1:3, y=4:6)
plot(foo$x, foo$y, type="n", axes=F)
points(foo$x, foo$y)
axis(side=1, at=foo$x, lty=0) #would like to figure out way to keep tick
marks, but suppress axis line

	[[alternative HTML version deleted]]

Andrew Yee wrote:
> I've been trying to figure out a parameter that will let you separately
> adjust the parameters for the axis line from the tick mark.
>
> In the following example, I would like to suppress the axis line, but keep
> the tick marks.
>   
The source code is the ultimate reference. We have in do_axis in 
src/main/plot.c:

    if (doticks) {
        gpptr(dd)->col = col;/*was fg */
        GLine(axis_low, axis_base, axis_high, axis_base, NFC, dd);
        for (i = 0; i < n; i++) {
            x = REAL(at)[i];
            if (low <= x && x <= high) {
                x = GConvertX(x, USER, NFC, dd);
                GLine(x, axis_base, x, axis_tick, NFC, dd);
            }
        }
    }

and, as you see, there is no way the line parameters can change between 
the GLine calls, no hope of finding a magical par() setting. So I'm 
afraid you have to bite the bullet, do the relevant coordinate 
calculations, and use segments() do draw the ticks. (Or try convincing 
Paul Murrell to change the design, but that takes longer...).

-- 
   O__  ---- Peter Dalgaard             ?ster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907

You could try overwriting the axis with a white axis line
so it blends into the background.

plot(1:10, axes = FALSE)
axis(1)
axis(1, col = "white", tcl = 0)


On Mon, Jun 16, 2008 at 2:52 PM, Andrew Yee <yee at post.harvard.edu>
wrote:
> I've been trying to figure out a parameter that will let you separately
> adjust the parameters for the axis line from the tick mark.
>
> In the following example, I would like to suppress the axis line, but keep
> the tick marks.
>
> Thanks,
> Andrew
>
>
> foo <- data.frame(x=1:3, y=4:6)
> plot(foo$x, foo$y, type="n", axes=F)
> points(foo$x, foo$y)
> axis(side=1, at=foo$x, lty=0) #would like to figure out way to keep tick
> marks, but suppress axis line
>
>        [[alternative HTML version deleted]]
>
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