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
Related
I have a 2D plot and want to draw horizontal straight lines from a given data file, so that each data point of the file is represented as a horizontal straight line in the existing 2D plot.
My approach so far:
I've tried using the for command, but I don't know how to write the current data point into a formular like x = C where C is the value of the data point:
for [i=1:10] "data.dat" u 2 every ::i::i
... is not what I meant.
for [i=1:10] x = "data.dat" u 2 every ::i::i
... is not a valid gnuplot command.
And furthermore, the range of i is variable, so that is another problem I have to solve with this approach.
Using arrows:
Like this posts suggests: Adding Horizontal lines on 2D plot with gnuplot. But in that example the author didn't need to draw the lines from a data file.
Is there a good way to do this?
My question is more about math then the actual code.
When use the command
set logscale
on gnuplot 5.0 what is happening ?
It should represents the logarithmic values values of the x and y points.
But it doesn not seems to work properly. For example on my data I have x and y values smaller then 1 so I am expecting to see negative values for these values on the plot, but I see only postivie values.
What I am doing wrong ?
The logarithmic scale still shows the real values around the axes, just their distances are logarithmic. To really see the negative values, you need to really apply the log function:
plot "file.dat" using (log($1)):(log($2)) with lines
without setting the logscale.
A specific example might help to illustrate the effect of logarithmic scaling:
set xrange [0.1:10]
plot x**2
Let's plot this again, but this time on a logarithmic scale. Watch how the scaling of the x and y axes changes:
set logscale
replot
Good evening,
I have a problem with Gnuplot. I tried to sum up my problem to make the comprehension easier.
What I have : 2 sets of data, the first one is my experimental data, about 20 points, the second one is my numerical data, about 300 points. But the two sets don't have the same abscissa.
What I want to have : I want my numerical data be interpolate on the x-experimental abscissa.
I know it is possible to do that with Xmgrace (paragraph Interpolation at http://plasma-gate.weizmann.ac.il/Xmgr/doc/trans.html#interp) but with Gnuplot ?
What I want to have in addition : is it possible, then, to subtract the y-experimental data of my y-numerical data at the x-experimental abscissa points ?
Thank you in advance for your answer,
zackalucard
You cannot interpolate the ordinate values of one set to the abscissa values of the other. gnuplot has no mechanism for that.
You can however plot both datasets using one of the smoothing algorithms (check "help smooth") with common abscissa values (which might (be made to) coincide with the original values of one set.)
set table "data1.tmp"
plot dataf1 smooth cspline
set xrange [GPVAL_x_min:GPVAL_X_max] # fix xrange settings
set table "data2.tmp"
plot dataf2 smooth cspline
unset table
Now you have the interpolated data in two temporary files, and only need to combine them into one:
system("paste data1.tmp data2.tmp > correlation.dat") # unixoid "paste" command
plot "correlation.dat" using 2:4
(If you have a sensible fit function for both datasets, the whole thing becomes much easier : plot dataf1 using (fit1($1)):(fit2($1)))
You can use smoothing, this should do the trick
plot "DATA" smooth csplines
(csplines is just one options, there others, e.g. bezier)
But I don't think you can automatically determine the intersection of the smoothed curved. You use the mouse to determine the intersection visually, or alternatively fit some functions f(x) and g(x) to your curves and solve f(x)=g(x) analytically
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...
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.