Drawing perpendicular lines in between two paths

Question

I am an architect working in ancient sites for architectural documentation. I am now trying to make an oldschool landscape drawing, which includes the height curves. (contour lines)

So for that, I am trying to drawing perpendicular lines arrayed along one line, starting from it and ending at the next one. which, i need to do it atleast 750 lines.

so to sum up, I want to fill the gap in between two lines with lines which are perpendicular to the path they are starting from and ending at the next one.

Answer 1

If I got your question right, you want to draw something like a stairs. I will assume that one of the lines has an equation

a x + b y + c = 0

with nonzero a and b (special cases a=0 or b=0 are trivial). I will also assume that a^2+b^2=1 (if not, just divide the equation by 1/sqrt(a^2+b^2)).

Then if have the lengths of your lines L, and the coordinate of starting point is (x0,y0), then coordinates of other points, where perpendicular lines start are

(x_i, y_i) = ( x0 + (b L i)/(N-1), y0 - (a L i)/(N-1) )

where i runs fro 0 to N-1, and N is the number of points, that you need for your staircase.

Note: if points will go in the wrong direction, use the opposite sign

(x_i, y_i) = ( x0 - (b L i)/(N-1), y0 + (a L i)/(N-1) )

After you have points, where the perpendicular lines start, the parametric equations for each perpendicular line is

x_i(t) = x_i + a t D, y_i(t) = y_i + b t D

where t changes from 0 to 1 and D is the distance between your parallel lines.

Note: if perpendicular lines go to the wrong direction, change sign

x_i(t) = x_i - a t D, y_i(t) = y_i - b t D

That is more or less it)