Terrain visibility analysis

Can you see Vesuvius from Rotonda Diaz in Naples?

Short answer: From Rotonda Diaz in Naples, the mapped eastern-rim summit of Vesuvius is topographically visible over 16.8 km, with high model confidence and a summit margin of about +418 m. This does not guarantee a clear view past nearby structures or in haze, and does not apply to every street in Naples.

Vesuvius from Rotonda Diaz in Naples: Sightelo checks the 16.8 km line to the mapped eastern-rim summit, with a terrain profile and urban viewing limits.

View the calculation in Sightelo

Key figures

Observation point: Rotonda Diaz, ground-level waterfront promenade, Naples, Italy; Latitude, longitude: 40.83175, 14.23045; Modelled ground elevation: 2.1 m; Eye height: 1.7 m
Point of interest: Vesuvius, mapped eastern-rim summit, Italy
Target elevation: 1,281 m
Straight-line distance: 16.8 km
Direction to the summit: 93.4° (east)
Modelled summit clearance: +418 m

Terrain profile and line of sight

Detailed profile

Scroll horizontally to explore the full profile on a small screen.

Calculated terrain
Observer–summit sight line
Minimum visibility line
Elevation reference: 0 m

Terrain already includes modelled curvature and refraction (k = 0.13). The grey curve projects a constant elevation of 0 m using that model; it is not an observed sea level. Subtract it from the terrain curve to read elevation. Sight lines remain straight; no second curvature correction is applied. Vertical and horizontal scales differ.

At the summit, the target clears the modelled horizon by 418.0 m. No blocking terrain is calculated. The relief forming the horizon is 15.199 km from A.

The calculation models terrain, Earth curvature and standard atmospheric refraction. It does not model buildings, trees, clouds, haze or local atmospheric variations.

Calculated profile values

Distance (km)	16.8 km
Observer eye altitude	3.8 m
Summit altitude	1281.0 m
Minimum visible target altitude	863.0 m
Target margin above the modelled horizon	+418.0 m
Minimum local sight-line clearance	+24.1 m
Displayed / calculated samples	169 / 169
Excluded around A / B	200 m / 1500 m
Horizon-forming relief	15.1993 km

Audited calculation: 2026-10-22. The interactive calculator can recalculate with currently available elevation data.

What this example helps you study

The observation point is on the public Rotonda Diaz waterfront promenade. The target is the mapped highest eastern rim (OSM node 12995577013), using the INGV reference height of 1,281 m; it is neither the crater centre nor Monte Somma. The summit margin is about +418 m and minimum local clearance about 24 m. Nearby buildings, temporary installations and vegetation are not individually resolved; the first 200 m are excluded. Copernicus is a surface model, not a survey of bare ground. The grey 0 m curve is a model reference, not an observed sea surface.

Limits of interpretation

The calculation models terrain, Earth curvature and standard atmospheric refraction. It does not model buildings, trees, clouds, haze or local atmospheric variations.

Technical details

Observation point coordinates: 40.83175, 14.23045
Summit coordinates: 40.822608, 14.4292366
Terrain model: Copernicus DEM 90
Eye height: 1.7 m
Refraction used: Standard (k = 0.13)
Sample step: 100 m
Uncertainty threshold: 30 m
Observer exclusion radius: 200 m
Requested summit exclusion radius: 600 m

A positive value means the summit clears the modelled terrain horizon. A negative value means the summit lies below the minimum elevation required to clear that horizon. This value is not the local height of blocking terrain above the sight line.