gnuplot 4.6 errorbars on the fly - gnuplot

Since stats on datafile containing two columns in gnuplot 4.6 provides mean and sd, I was wondering if I can plot errorbars on the fly instead of creating a third column? Thanks!

Assuming a file data.dat with two columns, you could get those error bars with a command like:
stats 'data.dat' nooutput
plot 'data.dat' using 1:2:(STATS_stddev_y) with errorbars
What would this mean, however? All the points have the same standard deviation, which is the value for the whole data set.
I could provide a more complete answer if you describe your data format/data sets in more detail.

Related

Plotting heatmaps in gnuplot

So, here I am trying to plot heatmaps in gnuplot. I have a matrix-formatted text file (with row and column headers), and the command I am using to plot it is
plot "file.txt" matrix rowheaders columnheaders using 1:2:3 w image notitle
The output is this graph:
Obviously, the X and Y labels are useless like this. I believe the problem here is that gnuplot is extracting all labels from the file and plotting them. How would I go about reducing the amount of clutter in here, e.g. plotting every 10th label or so?
Thanks in advance.
Or just make the picture resolution bigger... for instance like 1920,1080 or bigger... like this:
set term pngcairo size 1920,1080
or make the tics numbers like 1000000 smaller and make a label to show that the numbers written on the tics are 1000000 bigger... or both:)
Sorry for my english...

Gnuplot - how can I get a figure with no point on it ? (I want to have only the axes, the title and the x- and y- labels)

I have to create a video presenting the evolution of some quantities as functions of time. I am creating images with gnuplot and I assemble them to make a movie. I am getting trouble generating the two first images: the first image is supposed to have no point on it (it is supposed to show only the title of the graph, the x and y axes and the labels of the axes) and the second one is supposed to have one single point on it.
Is it possible to create a graph containing no data on it with gnuplot?
Is it possible to create a graph containing one single point with gnuplot using an input file? The input file contains:
0 15
Thank you in advance for your answers,
Julien
To plot an empty graph, just plot a completely undefined function like
plot NaN
The main issue here is, that the autoscaling fails since there are no valid points. You must give a fixed xrange and yrange to get a plot:
set xrange [0:1]
set yrange [0:1]
plot NaN notitle
Plotting a single point works fine using
plot 'file.dat' using 1:2 with points
You'll get warnings saying Warning: empty x range [0:0], adjusting to [-1:1] and Warning: empty y range [15:15], adjusting to [14.85:15.15], but you get a plot. To remove the warnings, you must again provide a fixed xrange and yrange.

How to plot (isosurface!) a datafile with four columns (x,y,z,f(x,y,z))? Is is possible using gnuplot?

What are the possible ways to plot (isosurface!) a datafile with four columns (x,y,z,f(x,y,z))? Is it possible using gnuplot?
No, this is not possible with gnuplot, but you might want to use octave, which uses gnuplot as backend (still). There, see the isosurface function.

gnuplot gives me strange plot look

I could not describe how the plot looks like so I just use "strange" as I have no idea why gnuplot gives me such a plot. Here is the thing I am trying to do.
I have a data file with two columns, the first column is the file name and the second is the size of each file. Each column is more than 2 million rows. I just want to plot the distribution of file sizes. Here is my code
set terminal postscript landscape enhanced mono dashed lw 2 "Times" 18
outputfile = "sizedist.ps"
set output outputfile
binwidth = 0.05
bin(x,width)=width*floor(x/width)
plot [0:3.5][]'sizedist.out' using (bin(log10($2/1024),binwidth)):(1.0) smooth freq with boxes t "Binsize=0.05 dex"
set terminal x11
Ideally, it should be a single Gaussian-like bar plot, but it has many other plots over-layed (see my attachment). Any expert on gnuplot knows why this happened?
This happens if some of your data in the frequency plot does not have well defined values (such as NaN, inf etc.).
Since you are using a logarithmic function in the plot, you have to be careful with data that has values <=0. I guess you have files with size=0. In this cases log10 just gives you NaN and this messes up the counting procedure of the frequency plot.
Include a condition to your plot to fix this. For example:
plot [0:3.5][]'sizedist.out' using ($2>0?bin(log10($2/1024),binwidth):0):(1.0) smooth freq with boxes t "Binsize=0.05 dex"

custom y scale in plot for

I have a data file, looking like
550 1.436e+00 7.857e-01 5.906e-01 4.994e-01 4.574e-01 4.368e-01 4.260e-01 4.273e-01 4.296e-01 4.406e-01 4.507e-01 4.639e-01 4.821e-01 5.008e-01 5.156e-01 5.378e-01 5.589e-01 5.768e-01 5.970e-01 6.196e-01 6.422e-01 6.642e-01
The first column is for x-axis, the rest ones are for the y-axis, 22 curves totally.
I want to plot the data so that y tics represent cube roots of the values. Actually, I want my cubic curves to become linear, to show, that they're cubic in the normal coordinates (and it is fixed by my task to use these coordinates).
I tried to use the following command:
plot for [i=2:23] datafile using 1:(i ** .333) smooth cspline
It expects column number in place of i.
I know, the following is correct:
plot datafile using 1:($2 ** .333) smooth cspline
giving me the desired plot for my first line. But how do I modify this for plot for?
If you want the column number in place of i, you should use column(i) in the using specification.
plot for [i=2:23] datafile using 1:(column(i) ** .333) smooth cspline

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