Hi Christian,
Many thanks for your tips. I was finally able to get the expected
results following your indications. I started by plotting my reference
line at y=-100 using mathematical expression and the "samples at"
command. I make this transparent, so that I can stack the real value
(with a +100 offset) onto it. Adjusting the style make it look like a
ycomb with an offset.
Here is the code I used, hoping it might be useful to someone, and
that someone improve it:
\begin{tikzpicture}
\begin{axis}[stack plots = y, /tikz/ybar,
xmin=-101,xmax=101,
ymin=-90, ymax=5,
bar width=0pt,
mark size=1pt
]
\addplot[transparent, domain=-100:100, samples at={-100, -99,
..., 100}] {-100};
\addplot[blue,mark=*] table [x=eta, y expr=\thisrow{p} + 100] {data.txt};
\end{axis}
\end{tikzpicture}
There are 201 points in my data.txt:
eta p
-100 -1200
-99 -553
...
Thanks for your help!
Best regards,
Aurélien
2012/7/8 Christian Feuersaenger <cfeuersaen...@googlemail.com>:
> Hi Aurelien Coillet,
>
> thanks for your request!
>
> The feature that you ask for is unsupported: comb plots are supposed to
> start at 0 for every plot.
>
> The reason why I am writing so late is that I wanted to check how to use
> stack plots and/or the internal zerolevel functionality (which you mentioned
> in your private email) first...
>
> What you could do is to create a stacked plot - and stack your comb plot on
> top of some other plot and ensure that the other plot is actually invisible.
> Note that this internal zerolevel functionality is used by stacked plots -
> and all other plot handlers. If I am not mistaken, the values are explicitly
> reset to 0 by pgfplots (unless you have a stacked plot of course).
>
> A stacked plot would reconfigure your complete axis, that means it would
> probably affect all plots within the same axis. If you feel that what you
> want is a stacked plot, then this will help. If you are in doubt, the tool
> does not what you want - as already said, comb plots have been designed to
> start at 0.
>
> Best regards
>
> Christian
>
>
> Am 18.06.2012 10:27, schrieb aurelien coillet:
>
>> Hi,
>>
>> I'm trying to plot some data using the ycomb feature, but I have to
>> use a decibel unit, and therefore, my values are ranging from -90 to
>> 0. The problem is ycomb draws the line from 0 to the given value,
>> which is not relevant for this unit. So here is my question: Is there
>> a way to modify the starting point of the line in a ycomb plot (or its
>> cousins xcomb, bar, ...)?
>> I searched in the manual and in google, but couldn't find answers...
>>
>> Thanks for your reply. Best regards.
>>
>
--
Aurélien Coillet
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