contour plots in MATLAB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a contour plot in MATLAB?

A contour plot in MATLAB is a graphical representation that shows curves connecting points of equal value in a 3D surface, displayed in 2D. It helps visualize how a function changes over two variables.

beginner

Which MATLAB function is used to create a basic contour plot?

The contour function is used to create a basic contour plot in MATLAB. For example, contour(X, Y, Z) plots contour lines for matrix Z over grid defined by X and Y.

intermediate

How do you add labels to contour lines in MATLAB?

Use the clabel function after creating a contour plot. It adds numeric labels to contour lines to show their values, making the plot easier to understand.

intermediate

What is the difference between contour and contourf in MATLAB?

contour draws contour lines only, while contourf creates filled contour plots where the areas between lines are colored, giving a clearer visual of value ranges.

intermediate

How can you specify the number of contour levels in a MATLAB contour plot?

You can specify the number of contour levels by passing a number as the fourth argument to contour, like contour(X, Y, Z, 10) to draw 10 contour levels.

Which MATLAB function creates a filled contour plot?

A mesh

B contour

C plot

D contourf

The contourf function creates filled contour plots, coloring the areas between contour lines.

What does the clabel function do in contour plots?

A Adds labels to contour lines

B Changes contour colors

C Creates contour lines

D Removes contour lines

clabel adds numeric labels to contour lines to show their values.

How do you specify the grid points for contour plots in MATLAB?

A No need to specify grid points

B Using a single vector

C Using X and Y matrices

D Using a scalar value

You specify grid points with X and Y matrices that define the coordinates for Z values.

What does a contour line represent in a contour plot?

A Points with the same function value

B Random points

C Maximum values only

D Minimum values only

Contour lines connect points where the function has the same value.

Which command creates 20 contour levels in a plot?

A contour(X, Y, Z)

B contour(X, Y, Z, 20)

C contourf(X, Y, Z, 5)

D contourf(X, Y, Z)

Passing 20 as the fourth argument to contour sets 20 contour levels.

Explain how to create a basic contour plot in MATLAB and how to add labels to it.

Think about the functions used and what each input represents.

Describe the difference between contour and filled contour plots and when you might use each.

Consider how the plot looks and what information it shows.