If we want to plot that data in gnuplot we have to keep track of the current position manually by storing its (x,y) value as variables by Now suppose we have the same data points stored as relative coordinates in our data file, resulting in: This can be plotted in a straightforward manner and will result in Fig. Here, we define the starting point to be (0,0) and add to it the values from the first and second column for every line of the data file. Note, that the addition is always performed first, before the resulting point is plotted which means we get no point at (0,0). Now assume that we also want to add steps going from point to point as shown in Fig. Gnuplot has the steps plotting style to achieve this, but we have to be carefully regarding our (x,y) variables.įig. ( code to produce this figure, hist.fct, data) 1 Two different distributions of measured angles. 1 you see two different distributions of measured angles. That is, if column 2 is 0 and column 3 is 0.9 then point symbol will be say circle.They were both given as one dimensional data and plotted with a defined macro that is doing the histogram calculation. I wish to plot column 4 as x and column 5 as y such that symbols will be chosen from column 2 and 3. The title keyword within the plot command specifies the text to be displayed in the legend. You can also set it directly to one point as we have done it here in order to have enough space between the key and the tics. In addition to that, its position can be specified by set key top left etc. Generally the legend is enabled by the set key command. P(x) title 'Theory' with lines linestyle 1 Title 'Power' with yerrorbars linestyle 2, \ In the last plot we will add theoretical data and a legend to the graph: Plot 'battery.dat' using 1:($2*1000):($4*1000) with yerrorbars linestyle 1įor achieving this we have to set brackets around the expression and reference the column data with $column_number. We can avoid the set format command in the last plot by directly manipulating the input data: 4 Plot of the data from battery.dat with y errors ( code to produce this figure) Therefore we add a second line to the plot command to combine the points with a line. Using the yerrorbars plotting style it is not possible to combine the points by a line. Since we want to plot the y errors and the data we need three columns in the first line of the plot command. Then in the plot command using tells gnuplot which columns from the data file it should use. Therefore we set the format option to tell gnuplot to use “mantissa to base of current logscale”, see gnuplot’s documentation. The power values are stored in Watt in the data file, but only has values lower than 1. Plot 'battery.dat' using 1:2:4 with yerrorbars linestyle 1, \ Here we want not only to plot the data, but also show the error for the y value (the data is stored in the format: x, y, xerror, yerror). Therefore we use the battery.dat file from gnuplots demo files that contains data about the dependence of the power of the battery on the resistance. 3 Plot of the data from plotting_data3.dat in two different styles ( code to produce this figure)Īnother common task is to plot data with errorbars.
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