curves

I have a little issue with calculating coordinates. Given are airfoil profiles in two lists with the following exemplary coordinates: Example: x_Coordinates = [1, 0.9, 0.7, 0.5, 0.3, 0.1, 0.0, ...] y_Coordinates = [0, -0.02, -0.06, -0.08, -0.10, -0.05, 0.0, ...] diagram 1: The only known things about the profile are the lists above and the following facts: the first coordinate is always the trailing edge, in the example above at (x=1, y=0) the coordinates always run on the bottom/underside to the leading edge, in the example above at (0,0) and from there back to the trailing edge the profile

I have a set of points which I want to smooth using B-spline curves. My question is how can I implement B-spline curves to smooth these set of points? I want to implement this using c++. Here is a function for any given number of points: void Spline(double x[N+1],double y[N+1], // input double A[N],double B[N], // output double C[N],double D[N]) // output { double w[N]; double h[N]; double ftt[N+1]; for (int i=0; i<N; i++) { w[i] = (x[i+1]-x[i]); h[i] = (y[i+1]-y[i])/w[i]; } ftt[0] = 0; for (int i=0; i<N-1; i++) ftt[i+1] = 3*(h[i+1]-h[i])/(w[i+1]+w[i]); ftt[N] = 0; for (int i=0; i<N; i++) { A

I have a set of points "data" defining a curve that I want to plot with bezier smooth. So I want to fill the area below that curve between some pairs of x values. If I only had one pair of x values it's not that difficult because I define a new set of data and plot it with filledcu. Example: The problem is that I want to do that several times in the same plot. Edit: Minimal working example: #!/usr/bin/gnuplot set terminal wxt enhanced font 'Verdana,12' set style fill transparent solid 0.35 noborder plot 'data' using 1:2 smooth sbezier with lines ls 1 pause -1 Where the structure of 'data' is:

I have a file that contains 4 numbers (min, max, mean, standard derivation) and I would like to plot it with gnuplot. Sample: 24 31 29.0909 2.57451 12 31 27.2727 5.24129 14 31 26.1818 5.04197 22 31 27.7273 3.13603 22 31 28.1818 2.88627 If I have 4 files with one column, then I can do: gnuplot "file1.txt" with lines, "file2.txt" with lines, "file3.txt" with lines, "file4.txt" with lines And it will plot 4 curves. I do not care about the x-axis, it should just be a constant increment. How could I please plot? I can't seem to find a way to have 4 curves with 1 file with 4 columns, just having a

Here's the screenshot of what I am doing. Currently, I'm stuck from drawing a curved borders into this rectangle. My first solution was: draw a quartered circle behind the rectangle, but if I adjust the opacity of the shape, as you can see, the quartered circle gets shown. I know this is pretty basic for you guys but I'm not really good at math. I did try to reuse the computed edges of the arc and add the size of border but I got this as a result. I also think of bezier curves as a replacement but I think it is more efficient to just reuse the computed vertices and add all the missing ones.