How to make a line of fixed length?

Hi all,

I want to make a line that has a fixed length and it has a partciular direction. I would appreciate any suggestions for this. Thanks!

[Davide Masiello]

I am afraid you need to be clearer. By making, do you mean plotting?

Moreover, what do you mean with direction?

[Mariam Shahab]

Yes, by making, I meant plotting. As for direction, I mean the orientation of the line (i.e. the slope of the line).

Answer 1

[Star Strider]

It is relatively straightforward to write an anonymous function for this —

createLine = @(startpt, slope, len) [startpt(1) startpt(1)+len.*cos(atan(slope)); startpt(2) startpt(2)+len.*sin(atan(slope))];

slope = rand                                            % Scalar

slope = 0.9275

startpoint = rand(1,2)                                  % Two-Element Vector

startpoint = 1×2

0.2799 0.8866

long = 10*rand                                          % Scalar

long = 7.5515

linevec = createLine(startpoint, slope, long)

linevec = 2×2

0.2799 5.8167 0.8866 6.0217

Check = [tan(atan2(diff(linevec(2,:)), diff(linevec(1,:)))) hypot(diff(linevec(2,:)),diff(linevec(1,:)))]

Check = 1×2

0.9275 7.5515

figure
plot(linevec(1,:), linevec(2,:))
grid
axis('padded','equal')
title(sprintf('Line from (%.2f, %.2f) to (%.2f, %.2f), slope %.2f, length %.2f', [linevec(:,1); linevec(:,2); slope; long]))

Experiment with the ‘createLine’ function.

.

[Mariam Shahab]

Alright, thank you

[Star Strider]

As always, my pleasure!

Answer 2

[Vilém Frynta]

You can specify length with numbers of your choice.

You can specify direction numerically as well, you just need to use your imagination and get creative.

x = [1 11];
y = [2 22];
line(x,y);

[Mariam Shahab]

Thank you for your help