Nine days. Each ridgeline is one day's elevation, zero-baselined from its start.
The x-axis is the actual trip — 3,753 miles from
Philadelphia to California.
Days 1–4 are flat. The South, the Gulf plain, the Texas plateau.
Day 5 climbs. Austin to Terlingua: through the Hill Country, over Paisano Pass at 5,406 ft.
Days 6 and 7 stay high — the Chisos Basin, Big Bend, 5,764 ft above sea level.
Day 8 descends across the Sonoran. Day 9 drops below sea level at the Salton Sea, −61 ft, then ends at the Pacific.