gnuplot histogram : negative values go down instead go up - gnuplot

I try to generate a histogram plot with gnuplot. I have positive and negative values. Positive values go to the top of the chart, but negative values go to the bottom of the chart..
I would like to change the base for go up and go down
from 0 to -100 for example.
Maybe, it's not the good type of graphic to do that ?
I have tried this :
gnuplot -e "set terminal png size 20000, 1500; set yrange [-100:*]; set title 'VU meter 0'; set style data histogram; set style histogram clustered gap 1; set style fill solid 1 noborder; plot 'testVUmeter0.tsv' using 2:xticlabels(1)" > out.png
Thanks

As far as I know the plotting styles histogram and with boxes always start at y=0.
Assuming I understood your question correctly, you want to shift this zero level e.g. to -100.
As long as you do not need an advanced histogram style but just simple boxes, one possible solution could be to use the plotting style with boxxyerror. Compared to #meuh's solution, here, gnuplot automatically takes care about the y-tics.
Code:
### shift zero for boxes
reset session
$Data <<EOD
A -20
B -140
C 100
D -340
E +250
F 0
EOD
myOffset = -100
myWidth = 0.8
set style fill solid 1.0
set arrow 1 from graph 0, first myOffset to graph 1, first myOffset nohead ls -1
set style textbox opaque
plot $Data u 0:2:($0-myWidth/2.):($0+myWidth/2.):(myOffset):2:xtic(1) w boxxyerror notitle, \
'' u 0:2:2 w labels boxed notitle
### end of code
Result:

You can calculate a new y value at each point, taking into account some wanted offset. For example, setting bot=-20 to give a bottom y value of -20 you can refer to ($2-bot) to convert, say, -5 to -5-(-20)=15` above 0.
set terminal png size 400,300
set output "out.png"
set style data histogram
set style histogram clustered gap 1
set style fill solid 1 noborder
bot=-20
set yrange [0:*]
set ytics ("-10" -10-bot, "0" 0-bot, "10" 10-bot, "20" 20-bot, "30" 30-bot)
plot "data" using (($2)-bot):xticlabels(1) notitle, \
"" using 0:($2+3-bot):(sprintf("%d",$2)) with labels notitle
with data of
1 33
2 44
3 22
4 -12
gives the plot:

Related

gnuplot histogram chart with overlap

I would like to plot a bar chart or histogram like this in gnuplot.
I tried set style histogram rowstacked which is a start but it adds the columns on top of each other while I need them overlapped. Next is the issue of transparent color shading.
Thanks for your feedback.
UPDATE: user8153 asked for additional data.
The set style histogram clustered gap 0.0 is doing the cluster mode of the histogram bars. If you blur the eye it sort-of shows what I want but with overlap and transparent shading.
The only other histogram modes given in the docs are rowstacked and columnstacked. I never got a plot out of columnstacked so I discarded it. Now rowstacked stacks the histogram bars.
The overlay appearance is there but it is wrong. I don't want the stacked appearance. The histograms have to overlay.
Code :
set boxwidth 1.0 absolute
set style fill solid 0.5 noborder
set style data histogram
set style histogram clustered gap 0.0
#set style histogram rowstacked gap 0.0
set xtics in rotate by 90 offset first +0.5,0 right
set yrange [0:8000]
set xrange [90:180]
plot 'dat1.raw' using 3 lc rgb 'orange', \
'dat2.raw' using 3 lc rgb 'blue', \
'dat3.raw' using 3 lc rgb 'magenta'
Thanks for your feedback.
Given a sample datafile test.dat
-10 4.5399929762484854e-05
-9 0.0003035391380788668
-8 0.001661557273173934
-7 0.007446583070924338
-6 0.02732372244729256
-5 0.0820849986238988
-4 0.20189651799465538
-3 0.4065696597405991
-2 0.6703200460356393
-1 0.9048374180359595
0 1.0
1 0.9048374180359595
2 0.6703200460356393
3 0.4065696597405991
4 0.20189651799465538
5 0.0820849986238988
6 0.02732372244729256
7 0.007446583070924338
8 0.001661557273173934
9 0.0003035391380788668
10 4.5399929762484854e-05
you can use the following commands
set style fill transparent solid 0.7
plot "test.dat" with boxes, \
"test.dat" u ($1+4):2 with boxes
to get the following result (using the pngcairo terminal):
Using transparency as in user8153's solution is certainly the easiest way to visualize an overlap of two histograms.
This works even if the two histogram do not have identical bins or x-data-ranges.
However, the color of the overlap is pretty much bound to the colors of the two histogram and the level of transparency. Furthermore, if you want to show the overlap in the key you have to do it "manually".
Here is a solution where you can choose an independent color for the overlap area.
The overlap is basically the minimum y-value from both histograms for each x-value.
For this you need to compare the y-values for each x-value. This can be done in gnuplot with some "trick" by merging the two files line by line. This requires the data in a datablock (how to get it there from a file). Since this merging procedure is using indexing of datablock lines, it requires gnuplot>=5.2.0.
This assumes that you have the same x-range and bins for each histogram. If this is not the case, you have to implement some further steps.
Script: (works with gnuplot>=5.2.0, Sept. 2017)
### plot overlap of two histograms
reset session
# create some random test data
set samples 21
f(x,a,b) = 1./(a*(x-b)**4+1)
set table $Data1
plot '+' u 1:(f(x,0.01,-2)) w table
set table $Data2
plot '+' u 1:(f(x,0.02,4)) w table
unset table
set boxwidth 1.0
set grid y
set ytics 0.2
set multiplot layout 2,1
set style fill transparent solid 0.3
plot $Data1 u 1:2 w boxes lc 1 ti "Data1", \
$Data2 u 1:2 w boxes lc 2 ti "Data2"
set print $Overlap
do for [i=1:|$Data1|] { print $Data1[i].$Data2[i] }
set print
set style fill solid 0.3
plot $Data1 u 1:2 w boxes lc 1 ti "Data1", \
$Data2 u 1:2 w boxes lc 2 ti "Data2", \
$Overlap u 1:($2>$4?$4:$2) w boxes lc "red" ti "Overlap"
unset multiplot
### end of script
Result:

Gnuplot, skipping timedat tics, histogram

So, i need to make histogram of data by dates, but i have problem with xticlabel overlapping, so, i'm trying to find a solution how to skip xtics to avoid overlapping. Considering that dates are not integer tics, i was trying to solve it that way:
the .dat file
Time Dat 1 Dat 2
1 27-12-2016 12 2
2 28-12-2016 13 7
3 29-12-2016 17 2
4 30-12-2016 9 10
....
Is it possible to count xtic by first column, but show values in second column instead of values in first?
my code:
reset
dx=5.
n=2
total_box_width_relative=0.75
gap_width_relative=0.1
d_width=(gap_width_relative+total_box_width_relative)*dx/2.
d_box = total_box_width_relative/n
reset
set term png truecolor font "arial,10" fontscale 1.0 size 800,400
set output "test.png"
set datafile separator "\\t"
set title "Errors"
set print "-"
set xlabel 'x' offset "0", "-1"
set ylabel 'y' offset "1", "-0"
set key invert reverse Left outside
set key autotitle columnheader
set key samplen 4 spacing 1 width 0 height 0
set autoscale yfixmax
set yrange [0: ]
set xtics strftime('%d-%m-%Y', "27-12-2016"), 5, strftime('%m-%d-%Y', "15-01-2017")
set xtics font ", 7"
set ytics auto font ", 9"
set y2tics auto font ", 9"
set grid
set style data histogram
set style histogram cluster gap 1
set style fill transparent solid 0.75 noborder
set boxwidth 0.9 relative
set xtic rotate by -45 scale 0
plot 'datfile' u 3:xtic(strftime('%d-%m-%Y', strptime('%m.%d.%Y', stringcolumn(2)))), '' u 4
Before asking such a vague question, always reduce the script to a bare minimum which is required to reproduce the problem.
After removing all unnecessary stuff and fixing the plot command, here is what I end up with:
reset
set datafile separator "\t"
set yrange [0:*]
set style fill transparent solid 0.75 noborder
set boxwidth 0.9 relative
set xtic rotate by -45 scale 0
set key autotitle columnheader
set style data histogram
set style histogram cluster gap 1
plot 'file.dat' using 3:xtic(2) t col(2), '' using 4
Here, you already see one option to avoid overlapping of longer tic labels by rotating them.
Another possibility is to skip every n-th xticlabel. At this point you must understand how gnuplot creates histograms. Histograms don't use a conventional numerical axis, so you cannot simply use the dates as you normally would do when plotting lines. But gnuplot puts each bar cluster at an integer x-position and with e.g. xtic(2) you label every cluster with the string as given in the second column.
The expression xtic(2) is a short cut for xticlabel(2), which means xticlabel(stringcolumn(2)). Instead of using exactly the string in the second column, you can use here any expression which yields a string, including conditions. To only plot every second label check if the row number is even or odd with int($0) % 2 == 0 and use and empty string or the string from the second column:
plot 'file.dat' using 3:xtic(int($0)%2 == 0 ? stringcolumn(2) : '') t col(2), '' u 4

GNUPLOT - Two columns histogram with values on top of bars

yesteraday I made a similar question (this one). I could not display the value on top of bar in a gnuplot histogram. I lost many time because I couldn't find really good documentation about it, and I only can find similar issues on differents websites.
I lost many time with that but fortunately someone give me the solution. Now I am having a similar issue with an histogram with two bars, in which I have to put on top of both bars its value. I am quite near, or that is what I think, but I can't make it work properly. I am changing the script and regenerating the graph many times but I am not sure of what I am doing.
script.sh
#!/usr/bin/gnuplot
set term postscript
set terminal pngcairo nocrop enhanced size 600,400 font "Siemens Sans,8"
set termoption dash
set output salida
set boxwidth 0.8 absolute
set border 1
set style fill solid 1.00 border lt -1
set key off
set style histogram clustered gap 1 title textcolor lt -1
set datafile missing '-'
set style data histograms
set xtics border in scale 0,0 nomirror autojustify
set xtics norangelimit
set xtics ()
unset ytics
set title titulo font 'Siemens Sans-Bold,20'
set yrange [0.0000 : limite1] noreverse nowriteback
set y2range [0.0000 : limite2] noreverse nowriteback
show style line
set style line 1 lt 1 lc rgb color1 lw 1
set style line 2 lt 1 lc rgb color2 lw 1
## Last datafile plotted: "immigration.dat"
plot fuente using 2:xtic(1) ls 1 ti col axis x1y1, '' u 3 ls 2 ti col axis x1y2, '' u 0:2:2 with labels offset -3,1 , '' u 0:2:3 with labels offset 3,1
I am modifying the last code line, because is here where I set the labels. I have been able to show both labels, but in bad positions, I have also been able to show one of the labels in the right position but no the other. I have been able to show almost everything but the thing that I want. This is the graph that generates the script.
output.png
This is the source file that I use for generating the graph
source.dat
"Momento" "Torre 1" "Torre 2"
"May-16" 1500.8 787.8
"Jun-16" 1462.3 764.1
"Jul-16" 1311.2 615.4
"Ago-16" 1199.0 562.0
"Sep-16" 1480.0 713.8
"Oct-16" 1435.1 707.8
And that's the command that I execute with the parameters set
gnuplot -e "titulo='Energía consumida por torre (MWh)'; salida='output.png'; fuente='source.dat'; color1='#FF420E'; color2='#3465A4'; limite1='1800.96'; limite2='945.36'" script.sh
I think that is quite obvious what I am pretending, can someone help me?
Lots of thanks in advance.
Your script has several problems, the missing ti col is only one of them. (You can also use set key auto columnheader, then you must not give that option every time).
Don't use both y1 and y2 axis if you want to compare the values! Otherwise the correct bar heights are only a matter of luck...
Understand, how gnuplot positions the histogram bars, then you can exactly locate the top center of each bar. If you only use offset with char values (which is the case when you give only numbers), then your script will break as soon as you add or remove a data row.
The histogram clusters start at x-position 0, and are positioned centered at integer x values. Since you have two bars in each cluster and a gap of 1, the center of the first bar is at ($0 - 1/6.0) (= 1/(2 * (numberOfTorres + gapCount))), the second one at ($0 + 1/6.0):
set terminal pngcairo nocrop enhanced size 600,400 font ",8"
set output 'output.png'
set title 'Energía consumida por torre (MWh)' font ",20"
set boxwidth 0.8 absolute
set border 1
set style fill solid 1.00 border lt -1
set style histogram clustered gap 1 title textcolor lt -1
set style data histograms
set xtics border scale 1,0 nomirror autojustify norangelimit
unset ytics
set key off auto columnheader
set yrange [0:*]
set offset 0,0,graph 0.05,0
set linetype 1 lc rgb '#FF420E'
set linetype 2 lc rgb '#3465A4'
# dx = 1/(2 * (numberOfTorres + gap))
dx = 1/6.0
plot 'source.dat' using 2:xtic(1),\
'' u 3,\
'' u ($0 - dx):2:2 with labels,\
'' u ($0 + dx):3:3 with labels
Now, starting at the bars center you can safely use offset to specify only the offset relative to the bars top center:
plot 'source.dat' using 2:xtic(1),\
'' u 3,\
'' u ($0 - dx):2:2 with labels offset -1,1 ,\
'' u ($0 + dx):3:3 with labels offset 1,1
A second option would be to use the label's alignment: The labels of the red bars are right aligned at the bars right border, the labels of the blue bars are left aligned at the bars left border:
absoluteBoxwidth = 0.8
dx = 1/6.0 * (1 - absoluteBoxwidth)/2.0
plot 'source.dat' using 2:xtic(1),\
'' u 3,\
'' u ($0 - dx):2:2 with labels right offset 0,1 ,\
'' u ($0 + dx):3:3 with labels left offset 0,1
In any case, both options make your script more robust against changes of the input data.
This looks better :
plot fuente using 3:xtic(1) ls 1 ti col axis x1y1, '' u 3 ls 2 ti col axis x1y2, '' u ($0-1):3:3 with labels offset -3,1 , '' u ($0-1):2:2 with labels offset 3,1
You had 2 plots commands: only the first one was displayed.
Also, script.sh should be a bash script. This is a gnuplot script, so it should have another extension.
The problem is the ti col tab. You need to put it in every option, including labels and not only in bars. The right code is:
plot fuente using 2:xtic(1) ls 1 ti col, '' u 3 ls 2 ti col, '' u 0:2:2 ti col with labels offset -3,1 , '' u 0:3:3 ti col with labels offset 3,1
And that's how the picture is displayed now:
You can also avoid ti col and that is how it would look:

In a Histogram chart(clustered), How to put vertical text in place of some of the bars, depending on condition?

In Gnuplot, I am using a Histogram chart(clustered), but not all data points have valid values. In those places, I want to replace the bar with a vertical text saying "Cannot Serve". How do I do it?
My current code:
set style data histogram
set style histogram cluster gap 2
set boxwidth 0.9
set xtic rotate by -45 scale 0
set output "test.pdf"
plot 'data.txt' using 2:xtic(1) fs pattern 1 ti col, '' u 3 fs pattern 2 ti col
data file contains:
type "magnetic" "electric"
"high load" 12000 12721.033920
"med load" 15620.011886 15783.706215
"low load" 15636.000000 16254.000000
This is a super hacky way to do this. I modified your file to add a "NaN":
"high load" NaN 12721.033920
"med load" 15620.011886 NaN
"low load" 15636.000000 16254.000000
Now I plot everything with boxes where the position of each box is calculated with respect to the order in which the records appear in the data file (column 0). It is "manually" defined here, but you should be able to write a function that gets the xrange and the box separation based on the number of records and the number of columns per record as obtained from stats for example. Also the boxwidth would depend on those values.
set xtic rotate by -45 scale 0
ymax = 20000
set yrange [0:ymax]
nrecords = 3
ncolumns = 2
set xrange [0:nrecords+1]
# Calculate boxwidth from available space per column
gap = 1./ncolumns/5.
width = 1./ncolumns/2.-gap/2.
set boxwidth width
plot "data.txt" u ($0+1.-width/2.-gap/2.):($2) w boxes t "data1", \
"" u ($0+1.+width/2.+gap/2.):($3) w boxes t "data2", \
"" u ($0+1.):(ymax/6.):(stringcolumn(2) eq "NaN" ? \
"Cannot serve" : ""):xtic(1) w labels rotate by 90 offset \
first -width/2.-gap/2.,0 not, \
"" u ($0+1.):(ymax/6.):(stringcolumn(3) eq "NaN" ? "Cannot serve" \
: ""):xtic(1) w labels rotate by 90 offset first width/2.+gap/2.,0 not

Add a single point at an existing plot

I am using the following script to fit a function on a plot. In the output plot I would like to add a single value with etiquette on the fitting curve lets say the point f(3.25). I have read that for gnuplot is very tricky to add one single point on a plot particularly when this plot is a fitting function plot.
Has someone has an idea how to add this single point on the existing plot?
set xlabel "1000/T (K^-^1)" font "Helvetica,20"
#set ylabel "-log(tau_c)" font "Helvetica,20"
set ylabel "-log{/Symbol t}_c (ns)" font "Helvetica,20"
set title "$system $type $method" font "Helvetica,24"
set xtics font "Helvetica Bold, 18"
set ytics font "Helvetica Bold, 18"
#set xrange[0:4]
set border linewidth 3
set xtic auto # set xtics automatically
set ytic auto # set ytics automatically
#set key on bottom box lw 3 width 8 height .5 spacing 4 font "Helvetica, 24"
set key box lw 3 width 4 height .5 spacing 4 font "Helvetica, 24"
set yrange[-5:]
set xrange[1.5:8]
f(x)=A+B*x/(1000-C*x)
A=1 ;B=-227 ; C=245
fit f(x) "$plot1" u (1000/\$1):(-log10(\$2)) via A,B,C
plot [1.5:8] f(x) ti "VFT" lw 4, "$plot1" u (1000/\$1):(-log10(\$2)) ti "$system $type" lw 10
#set key on bottom box lw 3 width 8 height .5 spacing 4 font "Helvetica, 24"
set terminal postscript eps color dl 2 lw 1 enhanced # font "Helvetica,20"
set output "KWW.eps"
replot
There are several possiblities to set a point/dot:
1. set object
If you have simple points, like a circle, circle wedge or a square, you can use set object, which must be define before the respective plot command:
set object circle at first -5,5 radius char 0.5 \
fillstyle empty border lc rgb '#aa1100' lw 2
set object circle at graph 0.5,0.9 radius char 1 arc [0:-90] \
fillcolor rgb 'red' fillstyle solid noborder
set object rectangle at screen 0.6, 0.2 size char 1, char 0.6 \
fillcolor rgb 'blue' fillstyle solid border lt 2 lw 2
plot x
To add a label, you need to use set label.
This may be cumbersome, but has the advantage that you can use different line and fill colors, and you can use different coordinate systems (first, graph, screen etc).
The result with 4.6.4 is:
2. Set an empty label with point option
The set label command has a point option, which can be used to set a point using the existing point types at a certain coordinate:
set label at xPos, yPos, zPos "" point pointtype 7 pointsize 2
3. plot with '+'
The last possibility is to use the special filename +, which generates a set of coordinates, which are then filtered, and plotted using the labels plotting style (or points if no label is requested:
f(x) = x**2
x1 = 2
set xrange[-5:5]
set style line 1 pointtype 7 linecolor rgb '#22aa22' pointsize 2
plot f(x), \
'+' using ($0 == 0 ? x1 : NaN):(f(x1)):(sprintf('f(%.1f)', x1)) \
with labels offset char 1,-0.2 left textcolor rgb 'blue' \
point linestyle 1 notitle
$0, or equivalently column(0), is the coordinate index. In the using statement only the first one is taken as valid, all other ones are skipped (using NaN).
Note, that using + requires setting a fixed xrange.
This has the advantages (or disadvantages?):
You can use the usual pointtype.
You can only use the axis values as coordinates (like first or second for the objects above).
It may become more difficult to place different point types.
It is more involved using different border and fill colors.
The result is:
Adding to Christoph's excellent answers :
4. use stdin to pipe in the one point
replot "-" using 1:(f($1))
2.0
e
and use the method in 3rd answer to label it.
5. bake a named datablock
(version > 5.0) that contains the one point, then you can replot without resupplying it every time:
$point << EOD
2.0
EOD
replot $point using 1:(f($1)):(sprintf("%.2f",f($1))) with labels
6. A solution using a dummy array of length one:
array point[1]
pl [-5:5] x**2, point us (2):(3) pt 7 lc 3
7. Or through a shell command (see help piped-data):
pl [-5:5] x**2, "<echo e" us (2):(3) pt 7 lc 3
pl [-5:5] x**2, "<echo 2 3" pt 7 lc 3
8. Special filename '+'
pl [-5:5] x**2, "+" us (2):(3) pt 7 lc 3
It seems to be the shortest solution. But note that while it looks like a single point, these are like 500 points (see show samples) plotted on the same position.
To have only one point the sampling needs to be temporarily adjusted (see help plot sampling)
pl [-5:5] x**2, [0:0:1] "+" us (2):(3) pt 7 lc 3
9. Function with zero sampling range length
Shortest to type, but plotting as many points on top of each other as many specified with samples
pl [-5:5] x**2, [2:2] 3 w p pt 7 lc 3

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