I am looking for a palette in gnuplot for red color from very-light-red to deep-red. I found a script for black here http://gnuplot.sourceforge.net/demo_5.3/pm3dcolors.16.gnu
I tried by changing set palette functions red, red, red in the above script, but it is not working.
By "legend" do you really mean "palette"? The legend is the list of plot titles and samples; entries there will normally appear in whatever color the corresponding plot used. The palette is the color gradient used for pm3d plots. To define a gradient from white to deep red:
set palette defined (0 "white", 1 "dark-red")
test palette
If you want more precise control over how light/dark the two extremes are you can provide instead hexadecimal descriptions of the RGB components. E.g. the above command is equivalent to
set palette defined (0 "0xffffff", 1 "0x8b0000")
Related
I am trying to put labels in a plot using gnuplot. For example, I need to label "Object 1" as blue:
set label 6 at 313,200 'Object 1' center rotate by 70 front tc ls 3
But 3 is not the kind of blue which I need. There are many different websites that show corresponding colors and numbers in gnuplot but for labeling the numbers of colors are not relevant to gnuplot color numbers. Where can I find the relevant different color numbers for labels?
Just, for the sake of not letting this question appear unanswered:
gnuplot has 111 predefined colors, type show colornames or see them here: predefined gnuplot colors visualized, or as Michael O. says "mix" your color red, e.g. 0xff0000 according to the scheme 0xRRGGBB. Set your textcolor with ...tc rgb 0xff0000. You even can add transparency according to the scheme 0xAARRGGBB where AA is the alpha channel, 00 is opaque, ff is fully transparent.
I want to plot contour maps using Gnuplot.
I tried using the following command,
set palette rgbformulae 33,13,10
splot filename u 1:2:3
This is the image file I got using those commands.
But I want to give a white color scheme when the third column has a maximum value. How to do this?
There many, many options for palette choice. Without going into all of them, I suggest you try set palette cubehelix
That provides a color range from dark to white. Here is the output from
set palette cubehelix
test palette
I'm a novice in Gnuplot. Today I was plotting a simple txt file with two data columns, being the x and y coordinates of a cloud of points in the xy plane; I wanted to color them according to the position they occupied in the list, so I should have gone for something like:
plot "data.txt" u 1:2:0 lc palette
that produces what I want:
(desired plot)
By mistake, I omitted the "using" part of the command, so that I prompted:
plot "data.txt" lc palette
Now, the points still are plotted in the correct positions, so that gnuplot is automatically interpreting them as (x,y) coordinates... but the colors look like this:
(strangely colored plot)
I find this baffling since there's the possibility that I'm involuntarily highlighting some interesting feature of my data (which, by the way, consists of few iterations of a discrete recurrence for a set - the x=1.57 line you can see - of different initial conditions.
The question is: what criterion does 'lc palette' use to assign the parity I see to my points? What is its default behavior supposed to be in this case?
Thanks in advance!
EDIT: I don't know if it can be useful, but prompting 'show palette' I get:
palette is COLOR
rgb color mapping by rgbformulae are 7,5,15
figure is POSITIVE
all color formulae ARE NOT written into output postscript file
allocating ALL remaining color positions for discrete palette terminals
Color-Model: RGB
gamma is 1.5
I am making an intensity plot with gnuplot using the following commands.
set palette defined
plot 'specttest.csv' u 1:2:3 with points linetype palette
Is it possible to make the same plot with a grayscale palette, ranging from white to black or black to white with varying gray levels?
Gnuplot offers many ways to specify a palette. For a gray palette, the simplest command is
set palette gray
To have the palette from white to black, use
set palette gray negative
I would recommend to use these commands, since then you can also use gamma to add gamma correction to the palette. With test palette you can see how the actual palette looks like:
set palette gray positive gamma 1.5
test palette
Other possibilities would be
set palette defined (0 'black', 1 'white')
or with 3 being the function x (see show palette rgbformulae):
set palette rgbformulae 3,3,3
or
set palette function gray, gray, gray
Here is the example in http://gnuplot.sourceforge.net/demo/pm3dcolors.html
set palette rgb 21,22,23; set title "hot (black-red-yellow-white)";
The above code set the hot palette. However I want a reversed hot palette, say:
white-yellow-red-black.
Small least value map to white and largest value map to black.
Miguel's answer is correct. Rather than making the individual numbers negative, the command set palette negative also does the trick:
set pm3d map
set palette negative rgb 21,22,23
splot x
would produce what you wanted. You can split the command up too:
set palette rgb 21,22,23
set palette negative
is equivalent. You can use set palette positive to undo this modification, or set palette to restore all the defaults (including the colours). Try help set palette for the full list of things you can do.
Use negative numbers to invert the palette:
set pm3d map
set palette rgb 21,22,23
splot x
gives you
whereas
set pm3d map
set palette rgb -21,-22,-23
splot x
gives you