I have a bunch of data that I'm plotting as point plots. The data is simply a column for X and a column for Y. The catch here though is this is plotted using axes x2y2.
The x1y1 is used for a histogram. The X axis is the same range for both plots.
I know how to derive the X coordinate, but am wondering if there is an easy way to determine the Y value to use to draw an arrow. I want to draw an arrow callout for an arbitrary point on the point plot.
y1 and y2 are independent.
The coordinates for drawing the arrow can refer to different coordinate systems (first, second, character, screen, and graph, see help coordinates).
So, to draw an arrow e.g. from the top-middle of the plot (graph 0.5, graph 1) to x2 = 1, y2 = 2 (second 1, second 2) you would write
set arrow from graph 0.5, graph 1 to second 1, second 2 head
Related
Ok, so I have two data series graphed, like so.
These are two scatter plots, based on x and y values, that are produced using a combo chart. The orange scatter plot is an ellipse whose calculation is based upon aspects relating to the purple scatter plot. I have made the orange ellipse in order to... well... select the part of the purple scatter plot that I want to do other things with. Problem is, I don't know how to actually select the data points this area refers to.
The data for this chart is based upon four columns: A,B (forming the purple plot) and C,D (forming the orange plot). Reordering the columns makes little difference.
Implementing Anger's proposed solution below, all instances seem to return true. Also, there happen to be more scatter plot rows than there are ellipse rows, so I'm not sure how to solve that for the sake of comparison.
If you specify the equation of the ellipse (center point and semi-major/minor axes), you can use the equation of the ellipse to flag points that are inside or outside.
if( ((Ex-x)/Lx)^2+((Ey-y)/Ly)^2 < 1, "INSIDE", "OUTSIDE")
Where Ex, Ey are the coordinates of the ellipse's center; x, y are your data point's coordinates, and Lx, Ly are the semi-major and semi-minor axes.
Just by eye, I would say Ex = 1.8, Ey = 1.21, Lx = 0.6, and Ly = 0.5.
I am modelling a graph problem using gnuplot
I am plotting a circle with gnuplot using the following command
set xtics 1
set ytics 1
plot 'circles.txt' with circle
my circles.txt contains the follwoing data
0 0 3
the upmost point on this circle(center at origin and radius of 3 ) should be (0,3) but it is shown as (0,2) in this graph
how can i rectify this error?
Plotting with circles is intended for plotting the points as circles so they would be round regardless of axes scaling. As it is pointed in gnuplot documentation,
The radius is always interpreted in the units of the plot's horizontal axis (x or x2). The scale on y and the aspect ratio of the plot are both ignored.
You can plot with ellipses instead; from documentation on plot with ellipses:
2 columns: x y
3 columns: x y major_diam
4 columns: x y major_diam minor_diam
5 columns: x y major_diam minor_diam angle
so you plot this as
plot 'circles.txt' using 1:2:($3*2):($3*2) with ellipses
(ellipses use diameter, so the size should be the third column twice)
Or set object ellipse:
set object ellipse at 0, 0 size 6, 6
I have a data file with 3 columns: The first 2 are coordinates of a circle, the 3. are results . How can I convert this x-y-coordinates into a range of degree (range of the x-axis: 0 - 360). I want to show results in a XY-plot. I don't want to create a further column in my data file, I want to convert the values directly with gnuplot. Is this possible?
Just remember your high school geometry and how to convert Cartesian coordinates to polar coordinates. Suppose you have a Cartesian coordinate (x, y). Draw a line between this point and the origin. The angle θ between this line and the x-axis is related by tan θ = y/x and the distance r from the origin is sqrt(x2 + y2).
So your angle θ is just the arc tangent (inverse tangent) of y/x. In gnuplot, this is the atan() function. I'd write something like this:
set angles degrees
plot 'infile.dat' using (atan($2/$1)):3 with points
where column 3 is your "result" (the roughness) and columns 1 and 2 are your Cartesian coordinates. It uses the calculated θ value for the horizontal plotted axis and the roughness for the vertical plotted axis.
The set angles command lets you set the unit used by atan() to degrees or radians. Since you specified a range of 0-360, it is set angles degrees.
It will plot the points in the order as they appear in the file. Notice that depending on the order of points in your data file, the order of the points after this calculation may no longer be visually sequential, so this example uses with points.
1-How can I rotate my plot so y would be the new x axis and vice versa?
2- Change the maximum value of y axis from 60 to 100.
The plot is created by this script in the terminal :
set palette grey
plot 'color_map.dat' matrix with image
You can exchange the x and y axes with the using modifier. (Just like for ordinary plots, except that for matrix data, columns 1 and 2 are not in your data file, but are inferred.)
plot 'color_map.dat' matrix using 2:1:3 with image
If you actually just want to change the maximum value on the y (new x) axis, you would use set xrange[:100]. But it sounds like you might actually want to scale the data itself, in which case you could use
plot 'color_map.dat' matrix using ($2/60.*100):1:3 with image
Try help plot matrix for more details.
I am quite new to gnuplot. And I've got problem with secondary y axis. When I try to plot two curves into one graph with two different y axis, the second one is moved down a little bit. I mean that if you draw a straight line parallel to the x axis at y1 = 0, you get different y2 values. I want both y axes to start at the same point y1=0 ~ y2=0.
Here is the picture better describing my problem: