On Sat, 2005-10-08 at 16:37 +0100, Prof Brian Ripley wrote: > On Sat, 8 Oct 2005, Marc Schwartz wrote: > > > On Sat, 2005-10-08 at 09:28 -0400, Denis Chabot wrote: > >> Hi, > >> > >> A few times I tried to control the number and position of tick marks > >> in plots with the yasp or xasp parameters. For example, a y axis was > >> drawn by default with tick marks at 0, 20, 40, 80 and 100. I tried to > >> get tick marks every 10 by adding > >> > >> yasp=(0, 100, 10) > >> > >> but this had no effect at all. I know I can draw the axis and tick > >> marks manually, but often this simple option would suffice if I could > >> understand how to make it work. > >> > >> Thanks in advance, > >> > >> Denis Chabot > > > > > > I suspect that one problem you are having is that there is no > > par("xasp") or par("yasp")....unless these are typos and you are trying > > to use par("xaxp") and par("yaxp")? > > In any case, (0, 100, 10) is invalid syntax, and c(0, 100, 10) is needed.
Indeed. > > There is an 'asp' argument to some of the plot functions (ie. > > plot.default), but this has a different intention. > > > > par("xaxp") and par("yaxp") are not listed as read only pars in ?par, > > however, I cannot recall an instance where R does not overwrite the user > > settings during the calculation of the axes, whether passed as arguments > > to a plot function or set a priori via a par() call. > > Really? Try > > > plot(1:100, xaxt="n") > > par(xaxp=c(0, 50, 5)) # the value is reset at each plot > > axis(1) > > for how it works (but not inline, which is probably a bug). Ah....I had not thought about that 'par'ticular combination... ;-) Hence, not R.O. So it must be used _after_ a plot call, which makes sense. I had reached for my copy of Paul's book and on page 96 (last paragraph in section 3.4.5 on Axes), he suggests using the approach I elucidate below with axTicks(). I thought he might have some other ideas and that I was missing something. This is also referenced on page 70, third paragraph in section 3.2.5 on Axes. > > If you want explicit control over the tick marks, you will need to use > > axis(), perhaps in combination with axTicks(), after using 'xaxt = "n"' > > and/or 'yaxt = "n"' in the plot call, depending upon the circumstances. > > That is usually as easy. Agreed. Thanks, Marc ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html