Hi:
On Tue, Aug 16, 2011 at 5:48 AM, Johannes Radinger <JRadinger at gmx.at>
wrote:> Hello,
>
> I am a beginner with ggplot and after doing simple graphs (histogram,
segments etc.)
> some questions came up:
>
> 1) I tried to do a histogram, but nothing is displayed although it works
with another vector.
> I think it is because of the very small values (n=1000, min=1.222e-24 max,
1.890e-20).
> I used qplot(variable,geom="histogram")... If do it with the
standard plot function it works perfectly.
Similar problems have been reported before, but I thought it had been
fixed in recent versions. [I could be wrong, though...) Which versions
of R and ggplot2 are you using? (Report sessionInfo(),
please.)>
> 2) I want to use scale_colour_gradient(). Is there any reference where I
can
> find the predefined colour-palletes like rainbow etc. and how they look
like?
There is some discussion of this in Hadley's ggplot2 book (pp.
104-106). See also
http://had.co.nz/ggplot2/scale_gradientn.html
http://had.co.nz/ggplot2/scale_brewer.html
>
> 3) How can I change the white grid in the background? In some cases I'd
like to
> remove the white grid
A group of enterprising ggplot2 users recently put together a page of
user-defined themes for the community:
https://github.com/hadley/ggplot2/wiki/themes/
Another one, called 'theme_nothing' and authored by David Kahle of
Rice U., blanks out most of the options in a ggplot:
# david kahle
# sept 27, 2010
theme_nothing <- function (base_size = 12){
structure(list(
axis.line = theme_blank(),
axis.text.x = theme_blank(),
axis.text.y = theme_blank(),
axis.ticks = theme_blank(),
axis.title.x = theme_blank(),
axis.title.y = theme_blank(),
axis.ticks.length = unit(0, "lines"),
axis.ticks.margin = unit(0, "lines"),
legend.position = "none",
panel.background = theme_blank(),
panel.border = theme_blank(),
panel.grid.major = theme_blank(),
panel.grid.minor = theme_blank(),
panel.margin = unit(0, "lines"),
plot.background = theme_blank(),
plot.title = theme_text(size = base_size * 1.2),
plot.margin = unit(c(-1, -1, -1.5, -1.5), "lines")),
class = "options")
}
You could study these themes to get an idea how to create one of your
own that retains the features you desire.>
> 4) How are the ticks on the X-axis calculated? Can they be changed in a way
that
> always 5 ticks with the corresponding numbers (labels) are displayed on the
X-axis.
Yes; see http://had.co.nz/ggplot2/scale_continuous.html and note the examples.
There is also a list for ggplot2 apart from R-help; you can subscribe to it from
http://had.co.nz/ggplot2/
Look for the heading 'Mailing list'; the on-line help pages are
further down the page.
Follow-ups should probably be sent to this list rather than R-help.
HTH,
Dennis>
> Thank you very much
>
> Johannes
> --
>
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