Method and data

Sources

• Stadium shape: USGS 3D Elevation Program lidar, Michigan 31-county collection, 2016. First-return points gridded to 1 m. Field level, bowl edge, rim and both suite towers are measured, not drawn.
• Sun: NOAA solar position equations, checked against the suncalc library to within 0.01°.
• Section numbering: University of Michigan stadium seating notes (sections 1 to 44, clockwise from the east 50-yard line).
• Weather: ERA5 reanalysis via Open-Meteo, the same week in 2016 to 2025; forecast from Open-Meteo inside 16 days.

How shade is computed

Each section is sampled on 3 lines (left, centre, right) at every row, 13632 seat points in total. For each point the surrounding stadium surface is scanned in every direction the sun can come from to give a horizon profile. A seat is in direct sun when the sun is higher than that horizon. Games are sampled every 10 minutes for 3.5 hours.

Limits

• Row positions are spaced evenly up the measured slope (0.559 m per row, calibrated to the published 94 rows on the west sideline). Real row counts vary by a few rows section to section.
• The lidar is from 2016. Structures added later (for example new video boards) are not in the shadow model.
• Club, suite and press levels are not modelled as seats.

Downloads (CC BY 4.0)

• sun-by-section.csv: game, kickoff, section, minutes of sun, shade arrival
• sections.json: section geometry and row-by-row sightlines