National Mall Sightline & Monument Elevation Visualizer

DRAG OBSERVER ICON (⊙) ALONG PLAZA AXIS TO RECACULATE SIGHTLINE

Calibrated Vantage Presets

Observer Parameters

Observer Distance 1,200 ft

Eye Elevation 15 ft

Raycast & Occlusion Metrics

Subtended Angle (Arch)

11.77°

Visual arc from horizon

Vista Obscured

38.4%

Mall monumental cone

Ratio vs Lincoln (99')

2.53×

250 ft / 99 ft height

1910 Act Variance

+120.0 ft

Above 130 ft statutory cap

Statutory & Planning Context

The Height of Buildings Act of 1910 (Public Law 61-198) restricts commercial and public structures to 130 feet (or street width plus 20 feet). The proposed 250-foot arch exceeds this ceiling by 120.0 feet and stands 2.53× the height of Henry Bacon’s 1922 Lincoln Memorial.

Live Technical Telemetry Verification

Observer Dist (ft)	Eye Level (ft)	Arch Angle (deg)	Vista Obscured (%)	Ratio vs Lincoln	Height Act Delta (ft)
1200	15	11.77	38.4	2.53	+120.0