I am using gnuplot 4.6. Also, I know that a similar question was asked more than a year ago here. The answer to that requires to write a small bash script. I want to know if it is possible to achieve this from within gnuplot script, especially when gnuplot-4.6 has so many cool features added. I am trying to achieve something like this :
set xrange[xL:xU]
set yrange[yL:yU]
plot "file1.dat" using 1:2 w l lt 1 lw 1 lc 3,\
"file2.dat" using 1:2 w l lt 1 lw 1 lc 3
I am repeating the above process in a loop and the xrange & yrange parameters are being updated in each iteration. Also, I am saving the output of each iteration as some image file. Now, file2.dat is guaranteed to have some points in all iterations. BUT this is NOT true for file1.dat. Hence, I want gnuplot to skip plotting the file1.dat in case it is empty. Please note, that it is PERFECTLY OK in my case if no points are plotted from file1.dat.
This can be achieved easily using an if statement, provided there is some command in gnuplot to detect if a file has no points, without trying to plot it. In that case, the above code will look something like this :
set xrange[xL:xU]
set yrange[yL:yU]
if ("file.dat" not empty){
plot "file1.dat" using 1:2 w l lt 1 lw 1 lc 3,\
"file2.dat" using 1:2 w l lt 1 lw 1 lc 3
}else {
plot "file2.dat" using 1:2 w l lt 1 lw 1 lc 3
}
Please help me formulate the 'condition' of the aforementioned if statement.
Thanks & Cheers
Abhinav
I could not find any hack that used only gnuplot commands. As a result, I am posting a work around which takes the help of shell to find if file1.dat has any any lines of data or not.
The condition in the gnuplot script file will look like :
if(system("awk '{x++}END{ print x}' file1.dat")>0){
plot "file1.dat" using 1:2 w l lt 1 lw 1 lc 3,\
"file2.dat" using 1:2 w l lt 1 lw 1 lc 3
}else{
plot "file2.dat" using 1:2 w l lt 1 lw 1 lc 3
}
I still would be grateful if anyone can give me a gnuplot command only method.
Related
I have a datafile that has three columns :
1 1.0 1
2 1.5 2
3 0.0 3
4 1.2 2.5
5 1.0 1
6 1.1 5
where the first column is my X value, the second column is my Y value, and the third column is the line width. I'd like for each line segment to be plotted according to the third column line width.
I tried:
plot 'file1.dat' using 1:2:3 with lines lw var
But I get undefined variable: var error.
Is this possible in gnuplot?
Thanks.
If you define column 3 as the linewidth between points n and n+1 (so the value of col. 3 of the row will be ignored) you can cheat:
stat 'file1.dat'
n=STATS_records
plot for [i=0:0] 'file1.dat' using 1:2:(alma=$3) every ::i::i w l lc 1 lw 1
plot for [i=0:n-1] 'file1.dat' using 1:2:(alma=$3) every ::i::i+1 w l lc 1 lw alma notitle
OR
plot 'file1.dat' u 0:1
n=GPVAL_DATA_X_MAX
plot for [i=0:0] 'file1.dat' using 1:2:(alma=$3) every ::i::i w l lc 1 lw 1
plot for [i=0:n] 'file1.dat' using 1:2:(alma=$3) every ::i::i+1 w l lc 1 lw alma notitle
You need the first plot for[i=0:0] to 'initialize' variable 'alma'.
stat 'varwidth.dat' nooutput
n=STATS_records; prex=0; prey=0; SC=2 # How y-axis is expanded relative to the x-axis
plot for [i=0:n-1] for [try=0:1] '' using 1:((try==0?dx=$1-prex:1),(try==0?sl=($2-prey)/(dx==0?1:dx):1),(try==0?prex=$1:1),(try==0?prey=$2:1),$2+(w=$3/80*sqrt(1+(SC*sl)**2))/2):($2-w/2) every ::i::i+1 w filledcurves lc 1 notitle
This produces the correct line width (as opposed to the “line height”, as in the answer to a related question). I have no clue how to make the “lines” match where they join (seems to be impossible without support from inside gnuplot).
(This assumes that the data in the question is in a file varwidth.dat.)
As mentioned by #Christoph in the comments, you have N points (rows) and N linewidth values, but only N-1 connecting lines.
So, you have to decide which linewidth value should be applied to which line. Which one to skip? The first one or the last one? Here, the last one is skipped.
It's basically, a shortened version of #Tom Solid's solution. Actually, you can get the initial value already during the stats command.
As #Joce mentioned and #Ilya Zakharevich is suggesting in his answer, if you do not fear some extra effort you can also draw tapered lines.
Data:
# x y linewidth
1 1.0 1
2 1.5 2
3 0.0 3
4 1.2 2.5
5 1.0 1
6 1.1 5
Script: (works with gnuplot 4.6.0, March 2012)
### workaround for variable linewidth
reset
FILE = "SO/SO37925489.dat"
stats FILE u ((N=$0)==0?Lw0=$3:0) nooutput
set grid
plot for [i=0:N] FILE u 1:2:(Lw0=$3) every ::i::i+1 w l lw Lw0 lc rgb "red" notitle
### end of script
Result:
I want to plot a file with linespoints in Gnuplot but the line using all the data samples and the points using fewer data samples. For example the following file plots the data but the line is not visible at all.
set terminal png
set out "plot_sample.png"
plot [t=-1000:1000] t w linespoints pt 64 lt 10 ps 1.5
How to do it if I want to define a custom sampling interval for the points but use all the data samples for the line? I could do two separate plots in the same figure but then the key will show both of them separately.
Use pointinterval to reduce the number of plotted points, but keep all points for drawing the line:
set samples 100
plot x**2 w linespoints pointinterval 10
Use every to reduce the samples taken from file!
Plot the line and
the points in two part, and use notitle at one of them!
Don't forget to 'synchronize' the color of the 2 plots!
Something like:
plot [t=-1000:1000] 'data.dat' w l lt 10 lc 10 t 'something', '' every 10 w p pt 64 ps 1.5 lc 10 notitle
NOTES
Usage of every: plot 'alma.dat' every A:B:C:D:E:F
where
A is the data increment (every Ath)
B is the datablock increment (datablocks are separated by empty lines)
C/D is the first data/datablock (start from C/D)
E/F is the last data/datablock (end at E/F)
You can use all the features described above, but if you don't need, just leave it empty, eg. ...every 2 or every 2::1 or every 2::1:0 ect...
I have a file that I need to plot in a graph that looks similar to this:
gnuplot sample graph
Here is my file that I am trying to plot:
441.81 823.36 192765 3044.68 4242.61
X 2609.3 4901.96 8306.6 12058.18
1632.27 4098.15 9299.14 16295.19 24665.59
I can do a simple plot, but changing the line types and using a file is what I am having trouble with. I'm not sure how to get the data from the file into the plot and make it formatted like the sample image.
You probably should dig a little deeper into gnuplot. A good start is this article on plotting data.
Anyway, let's define three distinct line styles:
set style line 1 lc 'blue' lt 1 lw 2 pt 6 ps 1.5
set style line 2 lc 'red' lt 1 lw 2 pt 6 ps 1.5
set style line 3 lc 'green' lt 1 lw 2 pt 6 ps 1.5
Then, we can call the plot function on our inputFile:
plot 'inptFile' u 1:2 w lp ls 1, '' u 1:3 w lp ls 2, '' u 1:4 w lp ls 3
(u 1:2 stands for using 1:2 and means that we use the value in the first column as x-coordinate and the value in the second column as the y-coordinate. )
Note that our inputFile looks like this (i.e., each line contains a point's x and y-coordinate):
-1 2 3 4
0 1 2 4
1 2 4 16
2 3 16 8
Output:
I have used gnuplot succesfully to plot boxplots. But now I would like to stick to gnuplot for all my plotting needs and looking to do something that eg. Prism can do:
http://www.graphpad.com/support/faqid/132/
I only have two columns of data (before and after) and want all pairs to be joined up with a line. If anyone has any idea, it would be great.
That is not possible out of the box, so it requires some fiddling.
The xtics are set manually, 0 is the x-value of 'Before', 1 for 'After'. These numerical values must be used explicitely later in the plots.
The lines are plotted as arrows without heads. Using lc variable (i.e. linecolor variable), we can use the last column of the using statement to select the color from the respective line type.
The 'Before' points are plotted first. Unfortunately, there is no option pointtype variable, so I use the plot for iteration to assign each point a different pointtype (pt).
I use the stats command to determine the number of points to plot. To get the total count, I must sum up the records, which are the inside points, and the outofrange points, because the classification is done based on the first column's value, which conflict with the 'manual' xtics settings for the 'Before' and 'After' labels.
These are the main points. Of course, there are many other possibilities (using line styles etc.), but should be a good starting point.
The script is:
reset
file='beforeafter.txt'
set xtics ('Before' 0, 'After' 1)
set xrange [-0.2:1.2]
set offset 0,0,0.2,0.2
stats file nooutput
cnt = int(STATS_records+STATS_outofrange)
plot for [i=0:cnt-1] file using (0):1 every ::i::i with points lc i+1 pt (6+i) ps 2 t '',\
for [i=0:cnt-1] file using (1):2 every ::i::i with points lc i+1 pt (6+i) ps 2 t '',\
file using (0):1:(1):($2-$1):($0+1) with vectors nohead lc variable t ''
With the test data beforeafter.txt:
1 5.5
2 0.3
3 3
And you get the result:
Using line styles
Another variant uses line styles to set the color, line type, and point type. For the iterations you must use explicitely ls (i+1), whereas for the vectors the as variable (arrowstyle variable) is used. With the lc variable it is not possible to set different dash patterns for the arrows.
So here is a, in my opinion, much more readable and flexible variant:
reset
set termoption dashed
file='beforeafter.txt'
set xtics ('Before' 0, 'After' 1)
set xrange [-0.2:1.2]
set offset 0,0,0.2,0.2
stats file nooutput
cnt = int(STATS_records+STATS_outofrange)
set style line 1 lt 1 pt 5 ps 2 lw 2 lc rgb '#AE1100'
set style line 2 lt 2 pt 7 ps 2 lw 2 lc rgb '#6EB043'
set style line 3 lt 3 pt 9 ps 2 lw 2 lc rgb '#7777ff'
set for [i=1:3] style arrow i ls i nohead
unset key
plot file using (0):1:(1):($2-$1):($0+1) with vectors as variable,\
for [i=0:cnt-1] file using (0):1 every ::i::i with points ls (i+1),\
for [i=0:cnt-1] file using (1):2 every ::i::i with points ls (i+1)
With the result:
I have a data in file which I would like to plot using gnuplot. In the file, there are 3 data sets separated by two blank lines so that gnuplot can differentiate between the data sets by 'index'. I can plot three data sets separately via 'index' option of 'plot' command.
However, I am not sure how can I plot the data which is sum of 2nd column of all three data sets?
Note: all three data sets have same x data, i.e. 1st column
To do this the simplest thing would be to change your file format. Gnuplot manipulates columns pretty well. Since you are sharing the x data, you can change the file format to have four columns (assuming you are just plotting (x,y) data):
<x data> <y1 data> <y2 data> <y3 data>
and use a command like
plot 'data.dat' using 1:2 title 'data 1', \
'' u 1:3 t 'data 2', \
'' u 1:4 t 'data 3', \
'' u 1:($2+$3+$4) t 'sum of datas'
The dollar signs inside the parens in the using column specification allow you to add/subtract/perform other functions on columnar data.
This way your data file will also be smaller since you won't repeat the x data.
#Youjun Hu, never say that there is "no way" to do something with gnuplot. Most of the cases there is a way with gnuplot only, sometimes maybe not obvious or sometimes a bit cumbersome.
Data: SO16861334.dat
1 11
2 12
3 13
4 14
1 21
2 22
3 23
4 24
1 31
2 32
3 33
4 34
Code 1: (works with gnuplot 4.6.0, needs some adaptions for >=4.6.5)
In gnuplot 4.6.0 (version at the time of OP's question) there were no datablocks and no plot ... with table. The example below only works for 3 subdatasets, but could be adapted for other numbers. However, arbitrary large number of subdatasets will be difficult with this approach.
### calculate sum from 3 different (sub)datasets, gnuplot 4.6.0
reset
FILE = "SO16861334.dat"
stats FILE u 0 nooutput
N = int(STATS_records/STATS_blocks) # get number of lines per subblock
set table FILE."2"
plot FILE u 1:2
set table FILE."3"
x1=x2=y1=y2=NaN
myValueX(col) = (x0=x1,x1=x2,x2=column(col), r=int($0-2)/N, r<1 ? x0 : r<2 ? x1 : x2)
myValueY(col) = (y0=y1,y1=y2,y2=column(col), r<1 ? y0 : r<2 ? y1 : y2)
plot FILE."2" u (myValueX(1)):(myValueY(2))
unset table
set key top left
set offset graph 0.1, graph 0.1, graph 0.2, graph 0.1
plot for [i=0:2] FILE u 1:2 index i w lp pt 7 lc i+1 ti sprintf("index %d",i), \
FILE."3" u 1:2 every ::2 smooth freq w lp pt 7 lc rgb "magenta" ti "sum"
### end of code
Code 2: (works with gnuplot>=5.0.0)
This code works with arbitrary number of subdatasets.
### calculate sum from 3 different (sub)datasets, gnuplot>=5.0.0
reset
FILE = "SO16861334.dat"
set table $Data2
plot FILE u 1:2 w table
unset table
set key top left
set offset graph 0.1, graph 0.1, graph 0.2, graph 0.1
set colorsequence classic
plot for [i=0:2] FILE u 1:2 index i w lp pt 7 lc i+1 ti sprintf("index %d",i), \
$Data2 u 1:2 smooth freq w lp pt 7 lc rgb "magenta" ti "sum"
### end of code
Result: (same result for Code1 with gnuplot 4.6.0 and Code2 for gnuplot 5.0.0)