How to skip vectors and plot the n-vector with quiver ( 2D-vecor-vector field)

I want to know how to skip some rows by plotting a two-dimensional vector-field.

For example, let U and V be the coordinates and x and y the vector components as writen below:

U=[1 2 3 4 5 6 7 8 9 10];

V=[0 0 0 0 0 0 0 0 0 0];

x=[0 0 0 0 -1 1 0 2 1 2];

y=[1 2 -1 -2 0 0 0 0 1 2];

then I use quiver to plot the vector-field as follows:

Vector=[U' V' x' y'];

quiver(Vector(:,1),Vector(:,2),Vector(:,3),Vector(:,4),0,'LineWidth',2,'MaxHeadSize',.1); axis([0 12 -3 3])

Now it would be great if someone could tell me what I need to write to plot only every second, third or n-vector (row)

I thank you in advancoe for your help

Emerson

Answer 1

[the cyclist]

Put these two lines in before the quiver() command:

plotEveryThisMany = 2;
Vector = Vector(1:plotEveryThisMany:end,:)

This will index into "Vector" at every other element. This can be generalized to choose whatever elements you want to plot.

[Emerson De Souza]

Thank you,

it has been a great suggestion. It fixed my problem!!!

Do you also know how to skip data by plotting 2d-curves?

I frequent have to do with this issue and don't know how.

For example, let:

x = 0:pi/100:2*pi;

y = sin(x);

plot(x,y);

What should I write if I want to display only every n-ten data point?

Thank you in advance

Emerson

[the cyclist]

You could do it like this:

xToPlot = x(1:10:end);

yToPlot = y(1:10:end);

plot(xToPlot,yToPlot)

Answer 2

[Sachini Pathirana]

How can I use the same thing to select points in a 2D matrix? I have a mtrix of 695*1028 and i want to plot selected points using quiver.

Answer 3

[ali veli]

Hi. How do I get this vector graphic with quiver3