Gnuplot Plot Data With Error Bars
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by the various errorbar styles. In the default situation, gnuplot expects to see three, four, or six numbers on each line
Gnuplot Error Bars Style
of the data file -- either (x, y, ydelta), (x, y, gnuplot error bars histogram ylow, yhigh), (x, y, xdelta), (x, y, xlow, xhigh), (x, y, xdelta, ydelta), or (x, y, xlow, gnuplot error bars standard deviation xhigh, ylow, yhigh). The x coordinate must be specified. The order of the numbers must be exactly as given above, though the using qualifier can manipulate the order and
Gnuplot Set Bars
provide values for missing columns. For example, plot 'file' with errorbars plot 'file' using 1:2:(sqrt($1)) with xerrorbars plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars The last example is for a file containing an unsupported combination of relative x and absolute y errors. The using entry generates absolute x min and max from the relative error. The y error bar
Gnuplot Xyerrorbars
is a vertical line plotted from (x, ylow) to (x, yhigh). If ydelta is specified instead of ylow and yhigh, ylow = y - ydelta and yhigh = y + ydelta are derived. If there are only two numbers on the record, yhigh and ylow are both set to y. The x error bar is a horizontal line computed in the same fashion. To get lines plotted between the data points, plot the data file twice, once with errorbars and once with lines (but remember to use the notitle option on one to avoid two entries in the key). Alternately, use the errorlines command (see errorlines (p.)). The error bars have crossbars at each end unless set bars is used (see set bars (p.) for details). If autoscaling is on, the ranges will be adjusted to include the error bars. See also http://gnuplot.sourceforge.net/demo/mgr.htmlerrorbar demos. See plot using (p.), plot with (p.), and set style (p.) for more information. Next: Errorlines Up: Plot Previous: Zticlabels Contents Index Ethan Merritt 2007-03-03
ylow and yhigh, default format)" plot "err.dat" with errorbars will result in (gif mode) # this gnuplot error bars color should look the same set title "Demonstration of error bars (both
Gnuplot Boxerrorbars
ylow and yhigh)" plot "err.dat" using 1:2:3:4 with errorbars will result in (gif mode) set title "Demonstration gnuplot boxerrorbars example of boxes" plot "err.dat" with boxes will result in (gif mode) set title "Demonstration of boxerrorbars" plot "err.dat" with boxerror will result in (gif mode) set title http://gnuplot.sourceforge.net/docs_4.2/node140.html "Demonstration of xybars" plot "err.dat" using 1:2:3:4:5 with xybars will result in (gif mode) set autoscale set title "Demonstration of error bars (both ylow and yhigh)" set xlabel "Date\nTime" set timefmt "%y%m%d" set xdata time set key right set format x "%m/%d\n%y" plot "futures.dat" using 2:3:4:5 with errorbars will result in (gif mode) set title http://www.csse.uwa.edu.au/programming/gnuplot_demos/errorbar/errorbar.html "Demonstration of financebars" plot "futures.dat" using 2:3:4:5:6 with financebars will result in (gif mode) set title "Demonstration of candlesticks" plot "futures.dat" using 2:3:4:5:6 with candlesticks will result in (gif mode) set xrange [-3:65] set yrange [ 4:14] set timefmt "" set xdata "" set xlabel "" set format x "" set tics set title "Demonstration of error bars (only ydelta)" plot "err.dat" using 1:2:5 with errorbars will result in (gif mode) set title "Plot data file twice to get lines and errorbars" plot "err.dat" with lines, "err.dat" using 1:2:3:4 with errorbars will result in (gif mode) set logscale y set title "Demonstration of error bars (only ydelta) with y logscale" plot [-3:65] [1:100] "err.dat" using 1:2:5 with errorbars set nologscale y will result in (gif mode) set logscale x set title "Demonstration of error bars (only ydelta) with x logscale" plot [1:100] [4:14] "err.dat" using 1:2:5 with errorbars set nologscale x will result in (gif mode) set autoscale set nologscale set title "" woo@playfair.stanford.edu
in those tutorials using gnuplot, a command-line-driven plotting program commonly available on Unix machines (though available for other platforms as well). You may find it helpful to look at the other tutorials as well; this one is intended to follow https://www.cs.hmc.edu/~vrable/gnuplot/using-gnuplot.html them quite closely. The instructions and samples given correspond to version 3.7 running under Linux, http://www.gnuplotting.org/tag/errorbars/ but the results should be similar everywhere. If you are using an older version, however, you might find a few of the more advanced features missing. Introduction gnuplot seems almost the antithesis of Kaleidagraph: the the Kaleidagraph tutorial calls Kaleidagraph "an easy-to-use if somewhat limited graphics program". gnuplot is a not-quite-as-easy-to use, though extremely powerful, command-line plotting program. Running gnuplot is easy: error bars from a command prompt on any system, type gnuplot. It is even possible to do this over a telnet or ssh connection, and preview the graphs in text mode! For best results, however, you should run gnuplot from within X Window, so that you can see better previews of your plots. Entering Data All the data sets you use in gnuplot should be typed into a text file first. There should be one data point per line. gnuplot error bars Each data point will consist of several numbers: the independent variable, the dependent variable, and optionally error bars. Each of these fields should be separated by a tab. Actually, any number of fields may be specified on each line; this is useful if you have multiple measurements for each data point, for instance. For information about how to access this additional information in your plots, see (fixme: add section) below. You may include any extra information you want in the file, such as a description of the data, headings for each of the data columns, and so on, as long as each such line begins with the comment character, #. The dataset used in this example is available in the file cavendish.data. Plotting Functions Basic Plotting Plotting functions in gnuplot is really quite easy. Suppose you want to plot the function f(x) = exp(-x^2 / 2). In gnuplot, exponentiation uses **, not ^. So, after starting up gnuplot, at the gnuplot> prompt you would type: plot exp(-x**2 / 2) Usually, you'll want a little more control over your plot, at least specifying the ranges for the x- and y-axes. You can specify these in a [minimum:maximum] form before the function. Specify the x range first, then the y range. You may leave off the y range, or both. We can revise our previous plot command to: plot [-4:4] exp(-x*
the last entry we had mean and standard variation data for five different conditions. Now let us assume that we have only two different conditions, but have measured with three different instruments A, B and C. We have used a ANOVA to verify that the data for the two conditions are significant different. As a result the plot in Fig. 1 should be created. Fig. 1 Plot the mean and variance of the given data (code to produce this figure) Therefore we store our data in a format, that can be used by the index command in Gnuplot. Note that the data have two empty lines between the blocks in the real data file: # mean std # A 0.77671 0.20751 0.33354 0.30969 # B 0.64258 0.22984 0.19621 0.22597 # C 0.49500 0.31147 0.14567 0.21857 Now every instrument is stored in a different data block containing both conditions as columns. The color definitions and axes settings are done in a similar way as in the previous blog entry. Note that we have to define two more colors for the boxes, because we use three different colors. Also we define a black line to plot the significance indicator (arrow). set style line 1 lc rgb 'gray30' lt 1 lw 2 set style line 2 lc rgb 'gray40' lt 1 lw 2 set style line 3 lc rgb 'gray70' lt 1 lw 2 set style line 4 lc rgb 'gray90' lt 1 lw 2 set style line 5 lc rgb 'black' lt 1 lw 1.5 set style fill solid 1.0 border rgb 'grey30' The significance indicator is created by three black arrows and a text label: # Draw line for significance test set arrow 1 from 0,1 to 1,1 nohead ls 5 set arrow 2 from 0,1 to 0,0.95 nohead ls 5 set arrow 3 from 1,1 to 1,0.95 nohead ls 5 set label '**' at 0.5,1.05 center For the plot the index command is used to plot first condition A, then B and then C by using block 0,1, and 2 respectively. The x-position of the boxes for instrument A are slightly shifted to the left, the ones for C to the right by subtracting or adding the value of bs. The value of bs has the width of one box in order to plot the boxes side by side. # Size of one box bs = 0.2 # Plot mean with variance (std^2) as boxes with yerrorbar plot 'statistics.dat' i 0 u ($0-bs):1:($2**2) notitle w yerrorb ls 1, \ '' i 0 u ($0-bs):1:(bs) t 'A' w boxes ls 2, \ '' i 1 u 0:1:($2**2) notitle w yerrorb ls 1, \ '' i 1 u 0:1:(bs) t 'B' w boxes ls 3, \ '' i 2 u ($0+bs):1:($2**2) notitle w yerrorb ls 1, \ '' i 2 u ($0+bs):1:(bs) t 'C' w boxes ls 4 Tags: ANOVA, border, bo