How to tick the parameter in the plot of a parametric function?
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I have a plot of a parametric function, as in the following simple example:
t = linspace(0, 1, 1000);
x = t.^2;
y = t.^3;
figure
plot(x, y, '-')
axis([0 1 0 1])
axis square
xticks(0:.1:1)
yticks(0:.1:1)
xlabel('x')
ylabel('y')
title('Parametric Plot: x = t^2; y = t^3')
How can I add ticks for the parameter value along the curve, similar to the x- and y-ticks?
Thank you!
Bernhard
4 Comments
Adam Danz
on 29 Jul 2022
Edited: Adam Danz
on 29 Jul 2022
Moving my answer to here in support of the other answers added later.
What about using Grid lines?
t = linspace(0, 1, 1000);
x = t.^2;
y = t.^3;
figure
plot(x, y, '-')
axis([0 1 0 1])
axis square
xticks(0:.1:1)
yticks(0:.1:1)
xlabel('x')
ylabel('y')
title('Parametric Plot: x = t^2; y = t^3')
grid on
Or text objects
figure
plot(x, y, '-')
axis([0 1 0 1])
axis square
xticks(0:.1:1)
yticks(0:.1:1)
xlabel('x')
ylabel('y')
title('Parametric Plot: x = t^2; y = t^3')
idx = 800; %for the 500th point
hold on
plot(x(idx),y(idx), 'bo')
text(x(idx), y(idx), sprintf('[%.2f, %.2f]',x(idx),y(idx)), ...
'VerticalAlignment', 'Bottom', 'HorizontalAlignment', 'right')
Accepted Answer
Voss
on 29 Jul 2022
Edited: Voss
on 29 Jul 2022
t = linspace(0, 1, 1000);
x = t.^2;
y = t.^3;
tick_length = 0.04;
t_tick = linspace(0,1,21);
x_tick = t_tick.^2;
y_tick = t_tick.^3;
dxdt_tick = 2.*t_tick;
dydt_tick = 3.*t_tick.^2;
theta_tick = atan2(dydt_tick,dxdt_tick)+pi/2;
xx = x_tick+cos(theta_tick)*tick_length/2.*[-1; 1];
yy = y_tick+sin(theta_tick)*tick_length/2.*[-1; 1];
xx(end+1,:) = NaN;
yy(end+1,:) = NaN;
figure
hold on
line(xx(:),yy(:), ...
'Color','k', ...
'LineWidth',1, ...
'Clipping','off')
plot(x, y, '-')
axis([0 1 0 1])
axis square
xticks(0:.1:1)
yticks(0:.1:1)
xlabel('x')
ylabel('y')
title('Parametric Plot: x = t^2; y = t^3')
3 Comments
More Answers (2)
Les Beckham
on 29 Jul 2022
Try this (or something similar):
% Your original code
t = linspace(0, 1, 1000);
x = t.^2;
y = t.^3;
figure
plot(x, y, '-')
axis([0 1 0 1])
axis square
xticks(0:.1:1)
yticks(0:.1:1)
xlabel('x')
ylabel('y')
title('Parametric Plot: x = t^2; y = t^3')
% New code
tdisp = [0 .3:.1:1]; % times to mark
hold on
plot(tdisp.^2, tdisp.^3, '+') % mark the points
text(tdisp.^2 + .02, tdisp.^3, split(num2str(tdisp))) % add labels
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