When should I use a 2d contour plot?

Very dense data ● Showing density peaks and valleys ● Statistical density estimation

When should I avoid a 2d contour plot?

Sparse data ● Categorical variables

What are common mistakes with 2d contour plots?

Too few contour levels ● Using rainbow colormap

Relationship

2D Contour Plot

Contour lines showing density of points in 2D space, like a topographic map.

Weather Density

Temperature vs humidity clusters

View data (30 rows)

Chart data table: Weather Density
Temperature	Humidity
22	65
24	70
23	68
25	72
21	60
23	67
24	69
22	66
25	71
23	64
22	68
24	67
23	70
25	68
22	63
28	80
30	84
29	82
28	78
30	86
29	81
28	83
30	80
29	84
27	79
31	85
28	81
29	79
30	82
27	81

Make a 2d contour plot with your data

Use a 2d contour plot when…

Very dense data
Showing density peaks and valleys
Statistical density estimation

Avoid when…

Sparse data
Categorical variables

Data it needs

Property	Value
Min Rows	20
Min Columns	2
Column Types	numbernumber

Visual anatomy

Marks

contour linefilled area

Channels

positioncolor-luminance

Axes

x-quantitativey-quantitative

Guiding principles

ColorPerceptually Uniform Colormaps
Use sequential colormap for density levels
IntegrityZero Baselines
Pick 5-10 contour levels — too few hides modal structure, too many turns the chart into noise

Consider instead

Hexbin Plot

For binned density with discrete cells

Common mistakes

Too few contour levels
Using rainbow colormap

History

Roots in 19th-century topographic mapping (and Galton's bivariate density work, 1886); adapted to statistical density estimation through the 20th century.

Accessibility notes

Describe density peaks location and magnitude. Provide summary statistics.

Got data? Let's see what works.

Drop your CSV. You'll get a 2D Contour Plot plus four alternatives - ranked by which one actually fits your data best.

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Temperature	Humidity
22	65
24	70
23	68
25	72
21	60
23	67
24	69
22	66
25	71
23	64
22	68
24	67
23	70
25	68
22	63
28	80
30	84
29	82
28	78
30	86
29	81
28	83
30	80
29	84
27	79
31	85
28	81
29	79
30	82
27	81

Temperature	Humidity
22	65
24	70
23	68
25	72
21	60
23	67
24	69
22	66
25	71
23	64
22	68
24	67
23	70
25	68
22	63
28	80
30	84
29	82
28	78
30	86
29	81
28	83
30	80
29	84
27	79
31	85
28	81
29	79
30	82
27	81