I have a gnuplot script which plots a histogram. I used the following syntax:
set style data histogram
set style histogram cluster gap 2
set style fill solid
set logscale y
rgb(r,g,b) = int(r)*65536 + int(g)*256 + int(b)
plot 'histogram_data' using (column(0)):2:(0.5):(rgb($3,$4,$5)):xticlabels(1) w boxes notitle lc rgb variable
What the last line does is: using column 1 as x labels, column 2 as the height of the histogram bars, 0.5 as box width, and columns 3, 4 and 5 as the rgb values to colour the bars.
Now, the problem is that modifying the gap parameter in line 2 does not change in any way the spacing between bars, even though as far as I understand that is the correct way to adjust such spacing. I am using gnuplot 4.6 patchlevel 4.
I found a way to do this with boxes, though I do not consider it very clean:
plot 'histogram_data' u (column(0)*2+1):2 w boxes notitle lc rgb 'white',\
'histogram_data' u (column(0)*2):2:(rgb($3,$4,$5)):xticlabels(1) w boxes notitle lc rgb variable;
This command is plotting all the data of the main plot on even slots and a white box on odd slots. So the first line in the plot command is plotting the gaps between every box of the plot (the width of these gaps can be specified using the boxwidth property I think but I haven't tested this), while the second line is drawing the actual plot.
I could not find a way to do this with the histogram plotting style, keeping the variable colours specified in the data file.
Related
I want to create a simple histogram in gnuplot and want to adapt the color of the bars according to the data. Currently, I am struggling with the mapping between color and data.
Let's say I have the following data file:
X, 500.00, 100.00, 1
Y, 600.00, 200.00, 2
I generate the histogram with the following code:
reset
fontsize = 12
set terminal png
set output "file.png"
set style fill solid 1.00 border 0
set style histogram errorbars gap 2 lw 1
set style data histogram
set xtics rotate by -45
set grid ytics
set xlabel "label"
set ylabel "label"
set yrange [0:*]
set datafile separator ","
plot 'data.dat' using 2:3:4:xtic(1) ti "" lc variable
Now I want to create a mapping between the fourth column in the data and the color, e.g. 1 -> yellow, 2 -> blue.
I assumed that I can define something like the following
set style line 1 linecolor rgb "yellow"
set style line 2 linecolor rgb "blue"
but this code is not working since it defines styles and not colors. On the other hand I have read in the documentation that "rgb variable" is only available in 3D plotting mode (splot), so I think in this terms my whole approach might go in a wrong direction.
Does anyone know how to realise the mapping between data and line colors?
Have you tried with the command palette? I had the same problems some times ago. I wanted to make this plot (that is in some ways what you need)
So I used the number of elements in a column of the histogram to set the color of that column. My datafile looked like
#MY_FILE
...
26 0.02302 2302
28 0.02233 2233
30 0.02261 2261
32 0.02383 2383
34 0.02279 2279
36 0.02366 2366
38 0.02226 2226
40 0.02148 2148
...
#EOF
where the first row $1 was the n parameter, the second one $2 was my pdf (simply the histogram normalized) and the third $3 column was the number of occurrence int the bin. Then I used the last column as the parameter to color my graph with the command
set palette model RGB defined (1 "blue", 2 "red")
that create a gradient between the starting point 1 and the end 2. Then to use the palette i plotted with the line
p 'MY_FILE' u 1:2:3 w boxes palette
where the w boxes was the command to generate my histogram, and the palette (also pal) command was the command o set the color, which use the third column as specified in u 1:2:3, where the 1:2 is my histogram and 3 is the color gradient.
if you don't want the lateral strip of color (heatmap) just type in gnuplot
unset colorbox
Here's some documentation about palette command in gnuplot:
http://gnuplot.sourceforge.net/demo_5.0/pm3dcolors.html
type help palette on gnuplot
THIS could be particularly HELPFUL: http://www.gnuplotting.org/defining-a-palette-with-discrete-colors/
I have the below script, which works fine when I have a third column in the second data set. Now I want to get the first histogram being drawn w/ error bars, and the second w/o. I can remove the :3 from the second plot command but gnuplot will complain about not enough data specified for the second histogram. If I remove set style histogram errorbars ... but that would disable the error bars on the first histogram, too. Is there a way to plot two histograms in the same figure, where one doesn't have error bars.
set xlabel ""
set ylabel ""
set boxwidth 0.9 absolute
set style fill solid 1.00 border -1
set style histogram errorbars gap 1
set style data histograms
set yrange [-1.746917959031165368e-01:3.668527713965446857e+00]
unset key
set datafile commentschar "#"
plot '-' using 2:3:xtic(1) title "onehist",\
'-' using 2:3:xtic(1) title "otherhist"
-3.583733737468719482e-01 1.073847990483045578e-02 1.073847990483045578e-02
-3.382162153720855713e-01 2.274234220385551453e-02 1.329828426241874695e-02
2.261839509010314941e-01 2.859487235546112061e-01 8.173441886901855469e-02
e
-1.164875924587249756e-01 4.266476333141326904e-01
-9.633044153451919556e-02 5.953223109245300293e-01
-7.617329061031341553e-02 6.151663661003112793e-01
-5.601614341139793396e-02 9.624376893043518066e-01
e
I'm not sure if it is possible to do this generally, but you can draw your histograms without the errorbars and then add them afterwards with an additional plot command.
plot '-' using 2:xtic(1) title 'onehist',\
'-' using ($0-0.2):2:3 with yerrorbars lc 'black' pt 0, \
'-' using 2:xtic(1) title 'otherhist',\
I'm not entirely sure how to determine the range of the actual bars, so the error bars are not perfectly centered, but this will place them on your graph as requested.
The additional command uses the yerrorbars style (which is how the histogram bars are drawn) to draw the error bars.
However, this isn't the best way to draw histograms. Gnuplot will treat the x-axis as a category with values 0, 1, 2, 3, etc. Therefore, even though you have different x values in both of your lists above, they will become superimposed over each other (and the second plot will change the x-axis values set by the first).
For your example, I would recommend using the boxes and boxerrorbars style.
set style fill solid
set boxwidth 0.01
plot '-' using 1:2:3 with boxerrorbars, '-' u 1:2 with boxes
or if you need the error bars to be a different color, draw them separately
plot '-' using 1:2 with boxes,\
'-' using 1:2:3 with yerrorbars lc 'black' pt 0,\
'-' u 1:2 with boxes
I'm trying to plot a histogram in gnuplot, where the bars are characterized by their color (intensity) instead of their height (frequency). To do so, I want to fill each bar with a color corresponding to the third column (which stands for this intensity) of a data file, defined in a palette. All the bars have the same height y=1 and the same width dx=1. The important part of the script looks like
plot for [ii=0:N] 'data.dat' index ii u 1:2:3 w filledcu y1=0 lc palette
My problem is that the ii=0 takes the right color of the palette and fills the first bar, but from there on all the others are the same color ( same intensity ) than ii=0.
My data file looks like:
X Y Intensity
1 1 0.6
2 1 0.6
...
Any idea to fill with the right color ?
The filledcurves plotting style doesn't support color gradients, see Gnuplot filledcurves with palette.
Since you have the same height for every bar, you can use the boxes plotting style:
set style fill solid noborder
plot 'data.dat' using 1:2:3 with boxes lc palette
I'm using gnuplot in a bash script to draw several things.
For this special graphic, I need to print the amount of matrices (y axis) with the matrix size as the x-axis.
As the distribution can be pretty sparsed, I want to use a logscale for x and y. It works great with y, but gnuplot tells me I can't have a logscale for the x-axis when I'm using histogram style.
Any ideas to debug this? or on how to present the results using a similar way?
set style data histogram
set style histogram cluster gap 1
set style fill solid border -1
set logscale xy
plot '$res/histo-$ld-$lr-$e-$r' using 2:xtic(1) title 'Run'
The error is :
line 0: Log scale on X is incompatible with histogram plots
Thanks in advance.
Edit : btw, I was using gnuplot 4.4 patchlevel 4 and just updated to the newest version (i.e. 4.6 patchlevel 5)
Gnuplot histograms work a bit differently from what you might think. The x-axis isn't numeric. In your case the value in the first row, second column is placed at an x-value of 0 with the y-value taken from the second column and a manual label taken from the first column, first row. The values of the second row are placed at x=1 etc.
You can try using the boxes plotting style, which is used with a 'conventional' x-axis and supports a logscale in x:
set logscale xy
set offset 0,0,1,1
set boxwidth 0.9 relative
set style fill solid noborder
plot 'data.dat' with boxes
With the data file data.dat
1 1000
2 300
5 150
20 10
135 3
this gives the result (with 4.6.5):
In order to have a fixed boxwidth and a varying box distance, you can use a third column to specify a box width as percentage of the x-value:
set logscale xy
set offset 0,0,1,1
set style fill solid noborder
plot 'data.dat' using 1:2:($1*0.5) with boxes
Putting the actual values on the x-axis works as follows:
set logscale xy
set offset 0,0,1,1
set style fill solid noborder
plot 'data.dat' using 1:2:($1*0.5):xtic(1) with boxes
I have a file with 3 columns, the first 2 are the position x y and the 3rd one I use it for define the color so I have something like this:
set palette model RGB defined ( 1 'black', 2 'blue', 3 'green', 4 'red')
unset colorbox
plot "file" u 2:1:3 w points pt 14 ps 2 palette, "file2" u 2:1:3 w points pt 14 ps 2 palette
Now the question: Is it possible to have a proper legend with this kind of point and COLOR?.
Since the points will have different colors (according to the pallete) I want to specify what means each color in the legend.
The only solution I was thinking was to write somewhere in the plot some text with the character of the point (in this case pt 14) and specify the color... but is not really a solution right?
So please help!
There is no option for this, you need to fiddle a bit. Here is YAGH (Yet another gnuplot hack) ;)
Assuming that your values are equidistantly spaced, you can use the '+' special filename with the labels plotting style.
To show only the custom key, consider the following example:
labels="first second third fourth"
set xrange[0:1] # must be set for '+'
set yrange[0:1]
set samples words(labels) # number of colors to use
key_x = 0.8 # x-value of the points, must be given in units of the x-axis
key_y = 0.8
key_dy = 0.05
set palette model RGB defined ( 1 'black', 2 'blue', 3 'green', 4 'red')
unset colorbox
plot '+' using (key_x):(key_y + $0*key_dy):(word(labels, int($0+1))):0 \
with labels left offset 1,-0.1 point pt 7 palette t ''
This gives (with 4.6.4):
As the set samples doesn't affect the data plots, you can integrate this directly in your plot command:
...
unset key
plot "file" u 2:1:3 w points pt 14 ps 2 palette, \
"file2" u 2:1:3 w points pt 14 ps 2 palette, \
'+' using (key_x):(key_y - $0*key_dy):(word(labels, int($0+1))):0 \
with labels left offset 1,-0.1 point pt 14 ps 2 palette
But you need to set a proper xrange, yrange and the values of key_x, key_y and key_dy.
This is not the most intuitive way, but it works :)
I have an alternative solution posted here:
Using Gnuplot to plot point colors conditionally
Essentially you plot once without a legend entry, then make dummy plots (with no data) for each point color/label.