# CurveCalc

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**
Calculate the "Hidden Height"
**

- Hidden by the ground we stand on

- Disappeared behind the horizon

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Example:

On a sphere with a radius of 6371 km.

-Your viewing height is 345 m

-You are looking at an object 123 km away

-The object is hidden by 842 m of curvature

-The horizon is 66 km away

**Curvature of the Earth**

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From Wikipedia, the free encyclopedia

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The curvature of the earth is understood to be the fact that the shape of the earth corresponds approximately to a sphere and therefore deviates
from a tangential plane even over short distances. Because of the curvature of the earth, height measurements must be corrected accordingly.

**Calculation**

Calculated with an average Earth radius of 6371 km, the ideal Earth surface deviates from a tangential plane downwards (radially, towards the Earth's centre) as follows:

0.8 mm per 100 m

20 mm at 500 m

78 mm at 1000 m

1.96 m by 5000 m

7.85 m to 10,000 m