Category:Variable-radius pie charts

Pie charts have wedges representing three quantities:

• a first quantity represented by circumferential extent (angle) of each wedge in the manner of conventional pie charts
• a second quantity represented by the radius of each wedge, and
• a third quantity represented by the area of each wedge.

The three entities are mutually interrelated, as described in the following instructions.

INSTRUCTIONS for creating graphic representing some "amount" (quantity, like dollars, tons, etc) for "groups" (of persons etc;):

For each wedge n:

1. Recognize A_n = π * r_n² * f_n

— Area A_n is total "amount" in group(wedge) n

— r_n (radius) is "amount" per person in that group(wedge) n

— f_n is the fraction of the circle's circumference occupied by that wedge n. Adding f_n values for all n wedges must total 1.0 to make a full circle.

2. Solving #1 for each r_n: each radius r_n is proportional to sqrt(A_n/(π*f_n))

3. Choose a convenient scaling factor for the r_n values to fit your desired graphic size—must apply same scaling to r_n for all wedges.

Compare: Category:Variable-width bar charts