Draw a Circle Matlab Plot

# Drawing

# Circles

The easiest option to describe a circumvolve, is - obviously - the rectangle (opens new window) function.

but the curvature of the rectangle has to be set to 1!

The position vector defines the rectangle, the kickoff two values 10 and y are the lower left corner of the rectangle. The last two values ascertain width and height of the rectangle.

The lower left corner of the circle - yeah, this circle has corners, imaginary ones though - is the heart c = [3 iii] minus the radius r = 2 which is [x y] = [1 1]. Width and height are equal to the diameter of the circle, and so width = two*r; pinnacle = width;

In case the smoothness of the above solution is not sufficient, at that place is no style effectually using the obvious way of drawing an actual circle past use of trigonometric functions.

# Arrows

Firstly, 1 can employ quiver (opens new window) , where 1 doesn't have to deal with unhandy normalized figure units past use of annotation

Of import is the fifth argument of quiver: 0 which disables an otherwise default scaling, as this function is usually used to plot vector fields. (or use the belongings value pair 'AutoScale','off')

One can also add boosted features:

(opens new window)

If different arrowheads are desired, 1 needs to employ annotations (this answer is may helpful How practice I change the arrow head style in quiver plot? (opens new window) ).

The arrow caput size can be adjust with the 'MaxHeadSize' property. It's not consistent unfortunately. The axes limits need to exist set afterwards.

There is another tweak for adjustable arrow heads: (opens new window)

which yous tin telephone call from your script as follows:

# Ellipse

To plot an ellipse you tin can utilize its equation (opens new window) . An ellipse has a major and a minor axis. Besides we want to be able to plot the ellipse on unlike center points. Therefore nosotros write a function whose inputs and outputs are:

You can use the following function to get the points on an ellipse and then plot those points.

Exmaple:

(opens new window)

# Polygon(s)

Create vectors to hold the ten- and y-locations of vertices, feed these into patch.

# Unmarried Polygon

(opens new window)

# Multiple Polygons

Each polygon's vertices occupy one column of each of 10, Y.

(opens new window)

# Pseudo 4D plot

A (thou x n) matrix can be representes past a surface past using surf (opens new window) ;

The color of the surface is automatically set as function of the values in the (1000 x northward) matrix. If the colormap (opens new window) is not specified, the default one is applied.

A colorbar (opens new window) tin can be added to display the electric current colormap and point the mapping of information values into the colormap.

In the post-obit example, the z (1000 ten n) matrix is generated by the function:

over the interval [-pi,pi]. The x and y values can exist generated using the meshgrid (opens new window) part and the surface is rendered as follows:

(opens new window)

Effigy one

Now it could be the case that additional information are linked to the values of the z matrix and they are store in another (m x n) matrix

It is possible to add together these additional information on the plot by modifying the mode the surface is colored.

This volition allows having kinda of 4D plot: to the 3D representation of the surface generated by the outset (thousand 10 n) matrix, the fourth dimension will exist represented by the data contained in the 2nd (m x n) matrix.

It is possible to create such a plot past calling surf with 4 input:

where the C parameter is the second matrix (which has to be of the aforementioned size of z) and is used to define the colour of the surface.

In the following example, the C matrix is generated by the part:

over the interval [-pi,pi]

The surface generated by C is

(opens new window)

Effigy 2

Now nosotros can telephone call surf with four input:

(opens new window)

Figure iii

Comparing Figure 1 and Figure 3, we tin can notice that:

• the shape of the surface corresponds to the z values (the first (one thousand ten northward) matrix)
• the colour of the surface (and its range, given by the colorbar) corresponds to the C values (the first (m ten n) matrix)

(opens new window)

Effigy 4

Of form, it is possible to swap z and C in the plot to have the shape of the surface given by the C matrix and the color given by the z matrix:

and to compare Figure 2 with Figure four

(opens new window)

# Fast drawing

There are 3 main ways to do sequential plot or animations: plot(10,y), set up(h , 'XData' , y, 'YData' , y) and animatedline. If you want your animation to be smooth, yous need efficient drawing, and the three methods are non equivalent.

I go 5.278172 seconds. The plot function basically deletes and recreates the line object each time. A more efficient way to update a plot is to use the XData and YData properties of the Line object.

Now I get 2.741996 seconds, much better!

animatedline is a relatively new role, introduced in 2014b. Permit'southward see how it fares:

3.360569 seconds, not as skillful as updating an existing plot, simply all the same improve than plot(x,y).

Of course, if you lot have to plot a unmarried line, similar in this example, the 3 methods are most equivalent and requite shine animations. Just if you have more complex plots, updating existing Line objects will make a departure.

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Source: https://devtut.github.io/matlab/drawing.html

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