### 7.2.3 Polygonal paths: polygonplot
ligne_polygonale
linear_interpolate
listplot plotlist

You can draw a polygonal path with either polygonplot or
listplot.

Given a list of points (a two-column matrix) or two lists (the x
coordinates and the y-coordinates), the polygonplot (or
polygonscatterplot) command
will draw the polygonal path through the points, from left to right
(so the points are automatically ordered by increasing
x-coordinates). If you enter

polygonplot([0,1,2,3,4],[0,1,4,9,16])

or

polygonplot([[0,0],[1,1],[2,4],[3,9],[4,16]])

or even

polygonplot([[2,4],[0,0],[3,9],[1,1],[4,16]])

you will get

If you give polygonplot a single list of numbers, then they will
be taken to be the y-coordinates and the x-coordinates will be
assumed to be integers starting at 0. If you enter

polygonplot([0,1,4,9,16])

If you want to get coordinates on the polygonal path, you can use the
linear_interpolate command. This command takes four
arguments; 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, and
x_{step}, the step size you want. (The values of x_{min}
and x_{max} must be between the smallest and largest
x-coordinates of the points.) You will get 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. For example, if you enter

linear_interpolate([[1,2,6,9],[3,4,6,12]],2,7,1)

you will get

[[2.0,3.0,4.0,5.0,6.0,7.0],[4.0,4.5,5.0,5.5,6.0,8.0]]

If you want to draw a polygonal path through points in an order
determined by you, you can use the listplot (or
plotlist) command. If you give listplot a list of
points, then you will get a polygonal path through the points in the
order given by the list. If you enter

listplot([[2,4],[0,0],[3,9],[1,1],[4,16]])

you will get

As with polygonplot, if you give listplot a single
list of numbers, then they will be taken to be the y-coordinates and
the x-coordinates will be assumed to be integers starting at 0.
If you enter

listplot([0,1,4,9,16])

you will get the same graph that you got with polygonplot.
However, unlike polygonplot, the listplot command
can’t be given two lists of numbers as arguments.