I am using Gnuplot to successfully plot some time series data. However, the series are fairly dense (10,000's of samples in about 5 inches of space), and when I plot multiple series, it is hard to see underneath the series that was plotted on top. Is there any way to make the lines have a bit of opacity or transparency (i.e. make the line transparent so underneath lines are visible)?
Excel has this capability, but I would much prefer to use Gnuplot.
Below is a sample of what I'm talking about. You can't see the red lines under the green lines. I would actually like to add a third time series. I am plotting with the command:
plot [][-3:3] 'samples_all.csv' using 1:7 title 'horizontal' w l ls 1, '' using 1:8 title 'vertical' w l ls 2"
Good news! This has been implemented in gnuplot. Example syntax is
plot x lw 10, -x lw 10 lc rgb "#77000000"
This will plot x as a red line and -x as a transparent black line (it looks gray). The first pair of two characters in the rgb specification define the alpha (transparency) channel ("#AARRGGBB"). The normal syntax ("#RRGGBB") still works.
old (gnuplot < 5.0 or so) answer for reference:
If you want to make lines plotted for time series data, the answer is no (see discussion here). You can't set a line style to be transparent. Transparency only works for filling under curves, and it has to be printed to the right terminal type.
I ran into this problem myself recently, I hope this feature will be added in a future version of gnuplot.
This may be what you're looking for.
Related
I try to create a nice waterfall map with gnuplot showing the development of an optical spectrum with current. My goal is to achieve something close to this :
A waterfall plot
I have tried this command
splot [][1160:1200][-80:-30] "Waterfall.txt" u 1:2:3 w l lw 3 lc rgb 'black'
The "Waterfall.txt" file has the format suggested in the accepted answer here Gnuplot: fence plot from data.
I have ignored z-data values lower than -80, substituting them with NaN.
The outcome is shown in the next image link.
My attempt
As you can see, compared with the previous figure, this is confusing to the reader. How can I fix it in order for it to be close to the first image and thus more clear to the viewer ?
Edit:
Thanks to #Ethan's answer it worked. The outcome is shown in the figure below. The only problem is the transparency of each fence, that reveals partially the subsequent fences.
The new attempt
Assume twenty 2D files each containing Y and Z:
Gnuplot version 5.2
filename(i) = 'silver.dat'
set pm3d scansauto
set style fill solid noborder
set xyplane at 0
set log z
unset key
splot for [k=20:1:-1] filename(k) using 1:(k):2:(1.0):2 with zerrorfill \
fc "white" lc "black" lw 2
I don't have your data files so I use the same file 20 times for the purpose of illustration. It is based on the zerror demo in the gnuplot distribution and online demo set.
Note that the base of each 'fence' is set to (z=1.0) rather than zero because of the log scale on z.
The figure shown was made using a newer gnuplot. It uses partial transparency and a fancier bounding box that isn't in 5.2
I have noticed that Gnuplot produces ugly artefacts when dealing to filled elements.
One instance is in the palette of the next figure:
Another example is when using filledcurves between two curves defined from points in ASCII files. In this case, you can see that rather than a real solid fill between the lines, the area is filled with number of strips, that only become apparent after zooming quite a bit, but that has very strong impact when rastering the image to png or similar:
This seems to be independent on the terminal. I have tried postscrip, pdfcairo and even tikz. Is there anything that can be done to improve this, or is this a hard limitation of Gnuplot?
Unfortunately, this is an artifact due to antialiasing in the document viewer when you have two filled polygons touching each other. This happens with the filledcurves plotting style, which composes the filled area of many quadrangles, as well as with the pm3d style (as you can see in the colorbox, which shows the same artifacts). See also
problematic Moire pattern in image produced with gnuplot pm3d and pdf output. for a concrete demo case.
There is a workaround, which however is very cumbersome. You must generate a filled polygon object with some script, fill that, use stats to determine the ranges, plot an empty plot (see e.g. Gnuplot - how can I get a figure with no point on it ? (I want to have only the axes, the title and the x- and y- labels)).
I assume, that you have a data file with three columns, and you would plot them with
plot 'test.dat' using 1:2:3 with filledcurves
Using the following very crude python script
from __future__ import print_function
from numpy import loadtxt
import sys
M = loadtxt(sys.argv[1])
print('set object 1 polygon ', end='')
for i in range(0,len(M)):
if (i == 0):
print('from {0},{1} '.format(M[i][0], M[i][1]), end='')
else:
print('to {0},{1} '.format(M[i][0], M[i][1]), end='')
for i in range(len(M)-1,-1,-1):
print('to {0},{1} '.format(M[i][0], M[i][2]), end='')
You can plot the filled curve with
# determine the autoscaling ranges
set terminal push
set terminal unknown
plot 'test.dat' using 1:2, '' using 1:3
set terminal pop
set xrange [GPVAL_X_MIN:GPVAL_X_MAX]
set yrange [GPVAL_Y_MIN:GPVAL_Y_MAX]
eval(system('python script.py test.dat'))
set object 1 polygon fillstyle solid noborder fillcolor rgb 'red'
plot NaN notitle
That, doesn't yet cover the problem with the jagged colorbox :(
I'm trying to graph an approximate solution (finite element method) to the Navier-Stokes equation. I've got a file called plotNSu1 that looks like this:
6 1 4.21022e-34
5.95 1 8.15227e-34
5.9693 0.970854 0.055197
6 1 4.21022e-34
5.9693 0.970854 0.055197
6 0.95 0.0941333
6 1 4.21022e-34
5.9693 0.970854 0.055197
5.92625 0.951192 0.0915468
5.9693 0.970854 0.055197
5.95 1 8.15227e-34
5.92625 0.951192 0.0915468
...
(The entries are x y z, grouped so that there's a blank line between each set of 4 points).
I use the following command to plot:
splot "plotNSu1" with lines
Butt I would like to make it look nicer, easier to read. (There's a small dip at one spot that's difficult to see, but is an important part of the solution).
I've found lots of examples using pm3d interpolate, but none seem to work for me. I've tried set style pm3d, and other set style commands, I've tried set pm3d map interpolate 10,10, and splot "plotNSu1" with pm3d, as well as so many other similar things stolen from the examples I've found that I can't keep track. Most of the time I just get an empty window with the color key and no plot, and often it sends me an empty 2d window.
I would like to have the color change with the contour of the plot, to make the little dip easier to see. Does anyone know how to do this? Here's one of the websites I've been trying to use, to see what I'm aiming for: http://gnuplot.sourceforge.net/demo/pm3d.html
I tried to post the image, but as I do not have enough reputation, I can't. But it's difficult to see what's going on because the graph is just all red.
I found a way to make this work, more or less, thanks to #Christoph's help and this other question suggested by stackoverflow: gnuplot pm3d plot triangle data
With my data in the file described above, in gnuplot I type:
set dgrid3d
set pm3d corners2color c2
splot "plotNSu1" using 1:2:3 with pm3d
The result isn't perfect, it looks a little choppy, but it basically does what I wanted, I can see the "dip" in my graph much better now.
Using gnuplot 4.6 patchlevel 1, with the following commands,
set grid linewidth 1 linecolor rgb"#888888"
set datafile separator ","
plot for [n=2:100] "data.csv" using 1:(column(n)) with lines linewidth 2
and the following example data in the file "data.csv",
time,S1,S2
0,0.00015,0
0.1,0.0001357256127053939,1.427438729460607e-005
0.2,0.0001228096129616973,2.719038703830272e-005
0.3,0.0001111227331022577,3.887726689774233e-005
0.4,0.0001005480069053459,4.945199309465411e-005
0.5,9.097959895689501e-005,5.902040104310499e-005
0.6,8.232174541410396e-005,6.767825458589604e-005
0.7,7.448779556871142e-005,7.551220443128858e-005
0.8,6.739934461758323e-005,8.260065538241677e-005
0.9,6.098544896108986e-005,8.901455103891014e-005
1,5.518191617571635e-005,9.481808382428365e-005
the resulting plot looks this:
Question: why does the grid only extend partway from the bottom, and not cover the whole plot? I tried a considerable amount of experimentation with the set xtics and ytics commands, arguments to grid, and more, and have not been able to get the grid to cover the whole plot. What am I missing?
Great question! In fact, the answer is that the grid does cover the whole plot. The problem is that the key is taking over. Try it again, but with an unset key in there before your plot command.
What's happening is that gnuplot is reserving space in the key for all of the columns which have no data. Nothing gets put in the space that was reserved since no reasonable data was found. Ultimately, this pushes the 2 lines that were visible out of the viewable canvas area as well.
I've reproduced this using the x11, png, postscript and pngcairo terminals.
Note that this behavior seems to be version dependent:
With gnuplot 4.4.2 (OS-X, png terminal)
With gnuplot 4.6.0 (OS-X, png terminal)
For those using gnuplot 4.4.4, perhaps there was a bug fix which made it work for gnuplot 4.4.4 and then a regression. It seems to persist into gnuplot 4.7.0 as well. I might file a bug report.
I am trying to plot (with Gnuplot) some basic 3d data from one file which is pretty much like that:
N M t1 t2 t3 t4
1000 1000 0.05268 0.04711 0.003947 0.003348
1000 2000 0.05743 0.04214 0.007577 0.006486
1000 3000 0.08465 0.04193 0.011329 0.009654
2000 1000 0.10726 0.08845 0.013593 0.012397
2000 2000 0.21065 0.10817 0.026525 0.024390
2000 3000 0.31528 0.16960 0.039772 0.036405
3000 1000 0.25415 0.14845 0.031082 0.026364
3000 2000 0.47345 0.25227 0.060887 0.051840
3000 3000 0.70612 0.36866 0.091311 0.077432
The idea is to plot it in some way I could see t1,t2,t3 and t4 for each N and M. It may be a lot of data to plot in only one graph, I know that. First of all, I have started with t1 plotting this way:
splot 'aux' u 1:2:3 w lp
and I get something like that
I would like to smooth a bit those lines and give them a different color. Is there any way to do something for it? Also any ideas to improve it in any other way would be very nice.
You're right, that is a lot of data. Changing the color of a particular dataset is pretty easy:
splot "dataset" using 1:2:3 w lines linecolor rgb "green"
Note that you can easily overlay multiple plots as follows:
splot "dataset" using 1:2:3 w lines lc rgb "green",\
"" using 1:2:4 w lines lc rgb "red"
A backslash at the end of a line is the gnuplot line-continuation character. Note that it must be the last character on the line. I've also used the pseudo-file "" which is just shorthand for the last file that gnuplot read. Finally, in this second version I used lc instead of linecolor. The gnuplot parser provides a lot of shorthand, although I suspect you already know this since you plotted w lp. (Also, please don't actually choose red and green for your plots. I think one of the biggest flaws in gnuplot is the default first 2 colors are red and green -- 1 in 20 people is red-green colorblind)
Smoothing is another story (unfortunately). plot does support a smooth option
plot "dataset" using 1:2 smooth beizer with lines #see help smooth for a list of options
Unfortunately, it appears that this option doesn't work for splot. At this point, I would write a small utility script to smooth the data in your favorite language using your favorite smoothing algorithm (plot "<utility.script mydata" u 1:2:3 ...). There are other (gnuplot-only) options, but they'd be ugly. What version of gnuplot do you have by the way? The gnuplot version is important to decide the best way to do the smoothing all in gnuplot if you decide that's still necessary.