There are choices to be made in creating a contour map. To get a heat map, something like this: set view map # 2D projection of 3D surface The figure you show is what I would call a heat map rather than a contour plot. Once plotted, what commands can I use to modify the GNUPLOT output? 推荐答案 However I need a 2d filled contour plot, this is the output from MATLAB: NU contains the matrix to plot, I already have the C code that gets the data and puts them in the same matrix format, from GNUPLOT documentation, splot uses the following format, so I also have the code to pass the data to a file 'data.txt' with the following format: # x, y, zĪnd it seems like its plotting the data correctly, but is plotting like so: Knowing the x and y positions of the minimum and maximum, we can easily set the arrows.I am porting some scripts from MATLAB to C and using GNUPLOT for plotting, in MATLAB I use the following command to plot: contourf(nU, 200,'linecolor','non') Obviously, these distinctions make sense only, if there are more than one minimum or maximum. That would have given the position of the last minimum of the data file. The minimum of this plot is nothing, but the x position of the first minimum. What this line does is substitute min_y, when the second column (whose minimum we extracted before) is equal to the minimum, and an undefined value, 1/0, otherwise. Having done that, we retrieve the positions of the minimum and maximum, by calling a dummy plot on the columns Set label 2 'Maximum' at max_pos_x, max_y 0.3 centreįirst, we retrieve the values of the minimum and the maximum by using a dummy plot. Set label 1 'Minimum' at min_pos_x, min_y-0.3 centre Set arrow 2 from max_pos_x, max_y 0.2 to max_pos_x, max_y 0.02 lw 0.5 Set arrow 1 from min_pos_x, min_y-0.2 to min_pos_x, min_y-0.02 lw 0.5 # Automatically adding an arrow at a position that depends on the min/max The rest of the plot is trivial, and this script results in the following graph: Therefore, if we take the square root of the sum of residuals divided by the number of degrees of freedom plus one, we get the standard deviation. However, we know that the number of degrees of freedoms is one less, than the number of data points, for we fit a function with a single parameter. One of them is the sum of the residuals, which is called FIT_WSSR, while another is the number of degrees of freedom, FIT_NDF. What we utilise here is the fact that the fit function also sets a couple of variables. Mean_y w l lt 3, 'stats2.dat' u 1:2 w p pt 7 lt 1 ps 1 Mean_y stddev_y with filledcurves y1=mean_y lt 1 lc rgb "#bbbbdd", \ Plot mean_y-stddev_y with filledcurves y1=mean_y lt 1 lc rgb "#bbbbdd", \ Set label 2 gprintf("Standard deviation = %g", stddev_y) at 2, min_y-0.35 Set label 1 gprintf("Mean = %g", mean_y) at 2, min_y-0.2 # Plotting the range of standard deviation with a shaded background Stddev_y = sqrt(FIT_WSSR / (FIT_NDF 1 )) Easy enough, and in just a couple of lines, we created this figure In the plotting section, we produce three labels, that tell us something about the data set, and plot the data range with shaded region. You can convince yourself that this returns the average of the data set. This plot does nothing but fills in the values of the minimum and maximum of the data set. Max_y with filledcurves y1=mean_y lt 1 lc rgb "#bbddbb", \Īt the beginning of our script, we just produce some dummy data, and call a dummy plot. Plot min_y with filledcurves y1=mean_y lt 1 lc rgb "#bbbbdd", \ Set label 3 gprintf("Mean = %g", mean_y) at 2, max_y 0.35 Set label 2 gprintf("Maximum = %g", max_y) at 2, max_y 0.2 Set label 1 gprintf("Minimum = %g", min_y) at 2, min_y-0.2 # Plotting the minimum and maximum ranges with a shaded background
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