Duncan Murdoch wrote:
> On 12/3/2007 12:21 PM, Biscarini, Filippo wrote:
>> Good evening,
>>
>> I am trying to add labels to the point of a simple plot, using the
>> text() function; the problem is that sometimes, if two points are too
>> close to each other, labels overlap and are no longer readable.
>> I was wondering whether there are options that I can use to prevent this
>> overlapping (by, for example, placing labels alternatively above and
>> below the plotted curve), or whether I should use another set of
>> graphical functions (grid or lattice packages).
>> Does anybody have suggestions?
>
> I don't think there are any functions to automatically avoid overlaps,
> but it is not hard to manually move some of the labels.
The OP might like to take a look at the orditorp function in package
vegan, which is designed to add information from complex ecological
data sets with many species to ordinations. It works out if a label
can be placed and if not draws a point. The OP would have to modify it
to try another place to plot, but that might be a basis from which to
work.
Of course, if this is a one-off project Duncan's solution is more than
adequate.
G
For example,
> you could alternate labels above and below with code like this:
>
> > x <- 1:10
> > y <- rep(0, 10)
> > plot(x,y)
> > text(x, y, rep("label", 10), pos=rep(c(1,3), 5))
>
> because the pos parameter can be specified separately for each observation.
>
> Duncan Murdoch
>
>>
>> Thank you,
>>
>> Filippo Biscarini
>>
>> PS: These are the lines of codes that I have been using to generate the
>> plot.
>>
>> plot(
>> prova$x,
>> prova$y,
>> type="b",
>> mar=c(0.5,0.5,0.5,0.5),
>> xlab="basepairs",
>> ylab=""
>> );
>>
>> text(
>> prova$x,
>> prova$y,
>> prova$lab,
>> pos=3,
>> offset=2,
>> cex=0.5
>> );
>
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Dr. Gavin Simpson [t] +44 (0)20 7679 0522
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