Custom colormaps in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a colormap in matplotlib?

A colormap is a set of colors used to map data values to colors in a plot, helping to visualize data intensity or categories.

beginner

How do you create a simple custom colormap using matplotlib?

You can create a custom colormap by using matplotlib.colors.LinearSegmentedColormap.from_list() with a list of colors you want to blend.

intermediate

What is the purpose of the from_list() method in colormaps?

It creates a colormap by blending a list of colors smoothly from start to end, allowing custom color gradients.

beginner

How can you apply a custom colormap to a heatmap in matplotlib?

Pass the custom colormap object to the cmap parameter in plotting functions like imshow() or pcolormesh().

intermediate

Why might you want to create a custom colormap instead of using built-in ones?

Custom colormaps let you choose colors that better match your data story, improve accessibility, or highlight specific data ranges.

Which matplotlib function is used to create a custom colormap from a list of colors?

A LinearSegmentedColormap.from_list()

B plt.custom_cmap()

C colors.create_map()

D colormap.new()

The correct function is LinearSegmentedColormap.from_list() to create a colormap from a list of colors.

What parameter do you use to apply a colormap to a matplotlib heatmap?

A color_map

B colormap

C color_scheme

D cmap

The parameter to apply a colormap is 'cmap' in matplotlib plotting functions.

What does a colormap do in data visualization?

A Maps data values to colors

B Changes plot size

C Adjusts font style

D Sorts data points

Colormaps map data values to colors to help visualize data intensity or categories.

Which of these is NOT a reason to create a custom colormap?

A To improve accessibility

B To change plot title font

C To highlight specific data ranges

D To better match data story colors

Changing plot title font is unrelated to colormaps.

What type of object does from_list() return?

A A plot figure

B A list of colors

C A colormap object

D A color palette

from_list() returns a colormap object that can be used in plotting.

Explain how to create and use a custom colormap in matplotlib.

Think about making a color gradient and applying it to a heatmap.

Why might custom colormaps be important in data visualization?

Consider how colors affect understanding and clarity.