gnuplot setting line titles by variables - gnuplot

Iam trying to plot multiple data lines with their titles in the key based on the variable which I am using as the index:
plot for [i=0:10] 'filename' index i u 2:7 w lines lw 2 t ' = '/(0.5*i)
However, it cannot seem to do this for a fractional multiple of i. Is there a way around this other than to set the title for each line separately?

sprintf should provide all the functionality needed, e.g.,
plot for [i=0:10] .... t sprintf(" = %.1f", 0.5*i)
in order to use the value of 0.5*i with 1 decimal digit...

Related

Putting a value from an input data file into 'Set Label'

I'm plotting an animated surface in gnuplot and want to read in an average or sum of the mapped z values and include this in a label to be printed in the plot, so that I get a running total updated as the GIF progresses. It's probably straightforward, but I'm a "gnu"bie, so to speak, and find this system pretty confusing!
I've tried putting the running sum and average numbers in additional columns ...
splot 'output3.dat' index i:i using 1:2:(column(3), TD1 = strcol(4), TD2 = strcol(5)) with pm3d
but this doesn't plot, and the string variables TD1, TD2 don't seem to exist outside the splot command.
The command you show would indeed set variables TD1 and TD2 globally if you change the order of clauses in the serial evaluation expression (the comma-separated sub-expressions):
splot 'output3.dat' index i:i using 1:2:(TD1 = strcol(4), TD2 = strcol(5), column(3)) with pm3d
However, if the idea is to create a label using set label that will appear as part of the resulting graph, this won't work. The set label command would have to be executed before the splot command, so TD1 and TD2 will not have the correct values yet.
There is an alternative that might serve you better. Instead of trying to put this dynamically evaluate information in a label, put it in the plot title. Unlike a label, the plot title is evaluated after the corresponding plot is generated, so any variables set or updated by that plot will be current. [caveat: this is true for current gnuplot (version 5.4) but was not always true. If you have an older gnuplot version the title is evaluated before the plot rather than after].
Since current gnuplot also allows you to place the individual plot titles somewhere other than in the key proper, you have the same freedom that you would with a label to position the text anywhere on the output page. For example, if you want to sum the values in column 3 of the data file and print the total as part of a title above the resulting plot:
SUM = 0
splot 'foo.dat' using 1:2:(SUM = SUM+column(3), column(3)) with linespoints title 'foo.dat', \
keyentry title = sprintf("Points sum to %g", SUM) at screen 0.5 0.9
I used a separate keyentry clause because this allows to omit the sample line segment that would otherwise be generated, but it would also be possible to make this the title of the plot itself if you want that sample line.

gnuplot: simple beeswarm example

I have been struggling with a basic beeswarm plot from page 62 in this doc. I imagine they are skipping some details, and I'm not sure what actual data they used. I think in particular the problem is mapping a categorical/string variable to an X-axis value.
I used this data:
A 1
A 2
A 3
B 4
B 5
B 6
With this script:
set terminal png
set output "graph.png"
set jitter
plot "data.csv" using 1:2:1 with points lc variable
I get this error:
"graph_script" line 4: warning: Skipping data file with no valid points
plot "data.csv" using 1:2:1 with points lc variable
^
"graph_script" line 4: x range is invalid
In their demos gallery, I see something like set xtics ("A" -1, "B" 0) which could maybe help me to label already-numeric data better, but what if my data doesn't start off numeric to begin with?
Do I need something like (hash_string_to_large_int($1) % 2)? There must be an easier way!
As mentioned in the comments you have to "convert" your keys into numbers in order to plot them.
You can do this by creating a list with your unique keywords and defining a function to get the indices.
First, the following example creates some random data
The code after knows nothing about the keywords, so it creates the unique list from scratch from the random data.
Maybe there is (and I am not aware) a simpler solution with gnuplot only.
Code:
### bee-swarm plot with string keys
reset session
# create some random test data
myExts = '.py .sh .html'
set print $Data
do for [i=1:100] {
print sprintf("%s %d",word(myExts,int(rand(0)*3)+1),int(rand(0)*10+1)*5)
}
set print
# create a unique list of strings from a data stringcolumn
Uniques = ''
addToList(list,col) = list.( strstrt(list,'"'.strcol(col).'"') > 0 ? '' : ' "'.strcol(col).'"')
stats $Data u (Uniques = addToList(Uniques,1),0) nooutput
getIdx(key) = (_idx=NaN, sum [_i=1:words(Uniques)] (word(Uniques,_i) eq key ? _idx=_i : 0), _idx)
set offsets 0.5,0.5,1,1
set key noautotitle
set multiplot layout 1,2
set title "No jitter"
plot $Data u (idx=getIdx(strcol(1))):2:(idx):xtic(word(Uniques,idx)) w points pt 7 lc var
set title "With jitter"
set jitter
replot
unset multiplot
### end of code
Result:

Getting plot title and caption data from the data file

Consider the following file that I want to plot using gnuplot: Servos20211222_105253.csv
# Date/Time 2021/12/22, 10:52:53
# PonE=0,LsKp=200,LsKi=0,LsKd=250,HsKp=40,HsKi=0,HsKd=130,Sp=800,TDEC=1175137
#
# Rel. Time, currentPos, PosPID, currentSpeed, speedPID, Lag, ServoPos
0.00000,4693184,0,0,0,0,4693184
0.00000,4693184,2300,0,368,0,4693184
0.00391,4693185,2300,12,367,0,4693184
:
:
I would like to:
set the plot title to the date/time from the first comment record.
display the record that starts "# PonE" as a caption.
extract the value for TDEC and plot a horizontal line with the name "Target"
I have some influence over the format of the header records, so if (for example) it would be better that they were not comments but provided in some other way, then that can be done.
It is a common problem to get text values from files using only gnuplot. If you can use OS and shell dependent solutions, I'd suggest to use remove the comments from the file and try something like
set title "`head -1 Servos20211222_105253.csv`"
You can place text anywhere using set label <"label text">, where the label text can be the 2nd line from the file.
You can plot a straight line using plot:
p sin(x), 0.5 title "TDEC"
But instead of 0.5, you need to get the value using shell scripts again, e.g. the cut unix command.
There are ways with gnuplot only, although sometimes a bit cumbersome compared with using tools which you have available on Linux (or comparable tools which you need to install on Windows).
Update: shorter and "simplified" script
One possible gnuplot-only way:
set commentschar to nothing, i.e. ''
assign the columns to variables and/or arrays, e.g. myDate, myTime, P[1..9].
Merge P[1..8] into a multi-line string Params by "mis"-using sum (check help sum)
Convert P[9] into a floating point number TDEC for plotting
Script: (modified the data a bit just for illustration)
### extract values from headers with gnuplot only
reset session
$Data <<EOD
# Date/Time 2021/12/22, 10:52:53
# PonE=0,LsKp=200,LsKi=0,LsKd=250,HsKp=40,HsKi=0,HsKd=130,Sp=800,TDEC=1175137
#
# Rel. Time, currentPos, PosPID, currentSpeed, speedPID, Lag, ServoPos
0.00000,1300000,0,0,0,0,4693184
0.00200,1200000,2300,0,368,0,4693184
0.00391,1100000,2300,12,367,0,4693184
EOD
set datafile separator comma commentschar ''
array P[9] # array to store parameters
stats $Data u ($0==0 ? (myDate=strcol(1)[3:], myTime=strcol(2)) : \
sum [_i=1:9] (P[_i] = _i==1 ? strcol(_i)[3:] : strcol(_i) ,0 )) \
every ::0::1 nooutput
set datafile commentschar # set back to default
Params = P[1]
Params = (sum [_i=2:8] (Params=Params.sprintf("\n%s",P[_i]),0),Params)
set title sprintf("%s %s", myDate, myTime)
TDEC = real(P[9][6:]) # convert to real number
set label 1 at graph 0.02, first TDEC P[9] offset 0,-0.7
set label 2 at graph 0.02, graph 0.85 Params
plot $Data u 1:2 w lp pt 7 title "Data", \
TDEC w l lc "red" title "Target"
### end of script
Result:

print cvs with decription column and multiple rows

i've got a csv file with this content (Row = Title + 10 Values, Row = Line in chart)
column-count is known (but would be great if only the Title is needed and value count is open (but same for all rows)), row count is open
Test1;0,051;0,040;0,051;0,052;0,051;0,049;0,051;0,052;0,059;0,044
Test2;0,016;0,016;0,016;0,019;0,021;0,021;0,021;0,021;0,022;0,022
Test3;0,216;0,200;0,210;0,205;0,205;0,205;0,203;0,206;0,205;0,204
result in LibreOffice
now i want to print it with gnuplot
i tried it with
set xrange [1:10]
set yrange [0:2]
plot for [row=0:*] 'test.csv' matrix every :::row::row with lines
but that only gives me several error messages
"gnuplot.txt" line 7: warning: matrix contains missing or undefined values
"gnuplot.txt" line 7: warning: matrix contains missing or undefined values
"gnuplot.txt" line 7: warning: matrix contains missing or undefined values
"gnuplot.txt" line 7: warning: matrix contains missing or undefined values
would be nice if someone can give me a hint
Unfortunately, gnuplot doesn't like data in rows and doesn't have a transpose function. I guess there is a way to plot rows with matrix as you tried, but currently I don't see a direct way to include the rowheaders as key entry.
So, either you use an external tool and transpose your data or you use the cumbersome gnuplot-transpose-attempt below and then plot columns. At least, this should work for Linux as well as for Windows without the installation of extra tools.
Your decimal sign is ,. Since my standard decimalsign is ., I had to set:
set decimalsign locale 'french' # or 'german' might also work
Data: test.csv
Test1;0,051;0,040;0,051;0,052;0,051;0,049;0,051;0,052;0,059;0,044
Test2;0,016;0,016;0,016;0,019;0,021;0,021;0,021;0,021;0,022;0,022
Test3;0,216;0,200;0,210;0,205;0,205;0,205;0,203;0,206;0,205;0,204
Code:
### plot row data with rowheader as key entry
reset session
myFile = 'test.csv'
set datafile separator ';'
set decimalsign locale 'french' # or 'german' should also work
# transpose data
stats myFile u 0 nooutput
set table $Dummy
set print $DataTransposed
do for [i=1:STATS_columns] {
LINE = ''
do for [j=0:STATS_records-1] {
plot myFile u (a=stringcolumn(i)) every ::j::j with table
LINE = LINE.sprintf('%s', j < STATS_records-1 ? a.";" : a)
}
print LINE
}
set print
unset table
undefine $Dummy
plot for [i=1:STATS_records] $DataTransposed u ($0+1):i w l ti columnheader
### end of code
Result:

gnuplot single plot in different colors

I have a single column of data (say 100 samples):
plot 'file' using 1 with lines
But this data is segmented: 10 points, then 10 more, etc... and I'd like each block of 10 to appear in a different color. I did filter them to 10 separate files and used
plot 'file.1' with lines, 'file.2' with lines...
But then the X axis goes 0..10 instead of 0..100 and all 10 graphs are stacked. Is there a simple way to do that without having to generate fake X data ?
Depending on your detailed data format... the following is doing what I think you are asking for.
Your "fake x data" is called pseudocolumn 0, check help pseudocolumns. The color you can change with lc var, check help linecolor variable.
Code:
### variable line color
reset session
# create some test data
set print $Data
do for [i=1:100] {
print sprintf("%g", rand(0)*i)
}
set print
plot $Data u 0:1:(int($0/10)) w lp pt 7 lc var notitle
### end of code
Result:

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