Looking straight down on the house. The outer ring is the horizon and the center is directly overhead, so each band is one season's arc across the sky. Shading is the average power the array made while the sun sat in that patch.
The broad wedge is where the sun has actually been in two years: it never crosses into the north, and it climbs to —° at midsummer — a figure computed from latitude, not measured. A patch noticeably paler than its neighbors at the same height is one the array underperforms in, which is how a tree or a chimney would announce itself.
Built from — readings grouped into — patches. Patches with fewer than eight readings are left out, because one reading cannot tell a shadow from a passing cloud.
nonepeak distance from center is the sun's height