20.2.3  Polygonal paths

The polygonplot or ligne_polygonale command draws a polygonal path through given points.

• polygonplot takes one mandatory argument and one optional argument:
  • Optionally, xcoords, a list of x-coordinates. By default, the x-coordinates will be a list of integers starting at 0.
  • ycoords, a list of y-coordinates.
  You can combine two arguments into a matrix with two columns (each list becomes a column of the matrix).
• polygonplot(⟨xcoords,⟩ycoords) draws the polygonal path through the given points, from left to right (so the points are automatically ordered by increasing x-coordinate).

Examples

or:

or:

or:

The listplot or plotlist draws a polygonal path, but in an order determined by you.

• plotlist takes L, a list of points or a list of numbers (which will be taken as y-coordinates, with the x-coordinates being the integers starting at 0).
• plotlist(L) draws a polygonal path through the points in the order given by the list.

Unlike polygonplot, the listplot command cannot be given two lists of numbers as arguments.

Examples

If you want to get coordinates on the polygonal path, use the The linear_interpolate command will find coordinates on the polygonal path.

• linear_interpolate takes four arguments:
  • M, a two-row matrix consisting of the x-coordinates and the y-coordinates.
  • x_min, the minimum value of x that you are interested in.
  • x_max, the maximum value of x.
  • x_step, the step size that you want.
  The values of x_min and x_max must be between the smallest and largest x-coordinates of the points.
• linear_interpolate(M,x_min,x_max,x_step) returns a matrix with two rows, the first row will be [x_min,x_min+x_step,x_min+2x_step,…,x_max] and the second row will be the corresponding y-coordinates of the points on the polygonal path.

Example