Intersection point of two lines from the data set.

Hi, How points on a line can be calculated if you are given the lower(x1,y1) and the upper(x2,y2) points and a given speed from (x1,y1)to(x2,y2).

if you can guide. ?

Answer 1

[Star Strider]

For a linear plot like that, the easiest way would be to use the polyfit and polyval functions:

p = polyfit([x1; x2], [y1; y2], 1);                 % Fit Line To Known Points With Linear Approximation
x3 = ... SOME POINT OR VECTOR OF POINTS ...;        % Desired ‘x’ Values
y3 = polyval(p, x3);                                % Calculate ‘y’ Values

If ‘x’ is time and ‘y’ is position, the speed will be given by ‘p(1)’.

[Arsal15]

Sorry to ask again. I am confused in your variables?

Can you take these variables and guide me? As I have taken below. Now if I have another time instant like 5.5 which is in between [4.8133 and 5.9180] then what will be x and y coordinates of that point at instant 5.5? For sure that point will be on that line ?

if true
  x_position = [x(1) x(2)] = [0.0988   0.0442];
  y_position = [y(1) y(2)] = [8.2928   8.2941];
  time_at_positions  = [t(1) t(2)] = [4.8133  5.9180];
  speed_x_direction = [vx(1) vx(2)] = [-0.0132  -0.1592];
  speed_y_direction = [vy(1) vy(2)] = [-0.0003  0.0389];
  end

I will be thankful if you can guide me . As I am stuck on this point.

[Star Strider]

I would use the interp1 function:

x = [0.0988   0.0442];
y = [8.2928   8.2941];
t = [4.8133   5.9180];

tq = 5.5;

xy = interp1(t', [x; y]', tq)

xy =
    64.8597e-003     8.2936e+000

I’m still not certain I’m understanding the problem, but this seems at least to be working toward a solution.

Answer 2

[Image Analyst]

See attached polyfit demo.

[Arsal15]

Can you please also look into my comment above and give your suggestion.

I will be grateful for your kind reply.