I have 2 datasets which I want to plot on top of each other. The first data set has a yrange of [-10:10], while the second has a range of [-2:2]. If I just plot them on top of each other in the usual linear scale, it is very difficult to see any features of the second data set:
Ideally I would like a nonlinear scale on the y axis to really emphasise what is going on between -2 and 2. I would like to design a y axis which looks like this:
So that most of the middle part of the plot is between -2 and 2. (I just manually added ytics in this figure) Does anyone know how to accomplish this via the "set link" command or something similar?
Related
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
I am trying to change my scale on gnuplot. I had a file from which I am plotting the fifth and sixth columns, and I am trying to change the x axis to a log scale. I am using
set logscale <2>
but it is saing that 'x' is an invalid axis. Is there a way to find out what the "name" of my 'x' axis is so that I can use this command?
From your question it's rather hard to see what you exactly want. Comment if this isn't what you're looking for. It sounds like you want to set the x axis to logscale base 2. It's done this way
set logscale x 2
In general, this is the command
set logscale <axes> <base>
I have a plot with exponential y axis range. I'm using multiplot command by inserting two images in one row. So due to this wide y axis range I'm loosing some space which I could use it to show my plots in a better way. I want basically something like this
How could i do this? I think for doing this I have do some math operations in the y axis range. Also what is the most convenient command to insert ( xE-10) at top left of the plot.
reset
set terminal epslatex size 16cm,18cm color colortext
set output new.tex
set key off
set format $%g$
set title "sinx"
set ylabel "[kNm]"
plot 1000000*sin(x)
This is not my exact code but it looks similar to this. The plot I have presented is a part of the multiplot code and I use 7 input files with time series data of 300 seconds at a time step of 0.02. The point I want to edit the y axis range (use some mathtematical expressions) and also include the term ( xE-10 ) on the top of the plot something like this
You can manually add the exponent with a set label .... For instance, the following function takes large values within the given interval:
plot[0:50] exp(x)
We can place the "x 10^21" manually in the desired place after dividing the plotted quantity by it:
set label 1 "{/Symbol \264} 10^{21}" at graph 0,1.025 left
plot[0:50] exp(x)/1e21
You have to be careful with the exact placement of the exponent since it might lie outside the plotting area, in which case you should lower the top margin with set tmargin .... Also, to use the "times" symbol, you need to pass the enhanced option to your terminal. With the epslatex terminal, you can use latex syntax: $\times 10^{21}$.
When plotting data which are very dense in small ranges of y, the logarithmic scale of gnuplot is the right scale to use.
But what scale to use when the opposite is the case? let's say most y values of different curves are between 90 and 100. In this case I want to use something like a inversed logarithmic scale. I tried a log scale between 0 and 1 but gnuplot wants me to choose a scale greater than 1
How can I achieve this?
You are right, you can use the inverse of the logarithmic function, which is the exponential. But gnuplot only supports logarithmic scales, so you have to do the conversion on your own:
plot "myData" using 1:(exp($2))
You will also have to handle the axis tics on your own. Either you just set them via a list like
set ytics ("0" 1.00, "1" 2.72, "2" 7.39, "3" 20.09, "4" 54.60, "5" 148.41)
or you use the link feature for axes of gnuplot 5. The following code uses the y2axis (right y-axis) to plot the data and calculates the tics on the left y-axis from the right one.
set link y via log(x) inverse exp(x)
plot "myData" using 1:(exp($2)) axes x1y2
Side note: Always remember that a non-linear axis is hard to understand. Logarithmic scales are common, but everything else not. So, be careful when presenting the data
I want to plot some data on x axis range [0:1] and y axis range [0:100], but on the x axis I have most of my data in range [0:0.1] and less data in the rest of the range. I thus wanted to expand the [0:0.1] range. I cannot use a logarithmic scale for the x axis as I have some data which is 0 and I cannot plot it if I use a logarithmic scale. Is there a way for plotting this in Gnuplot?
Ideally I would want to apply a logarithmic scale to the x axis, but start my plot from 0. That would help me to cover all the data and highlight the [0:0.1] range as well. Can it be done?
As you noted, it is impossible to have a logarithmic scale with a 0. I would use two graphs side by side, with separate x axes. You can do this through set multiplot layout 1,2.
I agree with Svante. An other option would be to introduce a second x-axis in the same plot. Then one x-axis would scale from 0:0.1 and the other would scale from 0:1. Depending on your data however this approach could be very confusing but I think especially if your data is primarily located between 0:0.1 this could work.