How Does Pyplot\'s Scatter Plot `s` Parameter Actually Determine Marker Size?

How Marker Size is Represented in Pyplot's Scatter Plot

The pyplot document for scatter plots mentions that the marker size can be specified using the s parameter, which takes a value in points^2. This can be a confusing way of defining size, as it is actually specifying the area of the marker. To double the width (or height) of the marker, one must increase s by a factor of 4, as the area is given by A = W*H.

This approach becomes especially relevant when scaling markers. Doubling the width of a marker increases its size by more than a factor of 2, as it increases its area by a factor of 4. To demonstrate this, consider a scatter plot where the marker sizes are scaled using a factor of 2^n (exponential growth) or 4^n (exponential growth of the area). The resulting plots show a much more apparent increase in size in the case of area growth.

In practice, the exact meaning of a "point" is arbitrary for plotting purposes. To determine the appropriate size of markers, one can scale all sizes by a constant until they appear visually reasonable.

Answering the Question

The question raised concerns the interpretation of the s parameter, particularly what it means when specifying s=100. To clarify, this value represents an area of 100 points^2, which does not directly translate to pixel dimensions. To determine the actual pixel dimensions, additional factors, such as resolution and DPI, must be taken into consideration.

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