**Known values:**

Baseline sloping distance ** AB **and

**height**

**of the observer.**

*h*_{1}Angles measured at A – Vertical angles ** α **and

*δ**(slope of ground between A and B).*

Angle measured at B** – **Vertical angle

**.**

*β***Solution:** Height of object above ground at position ** A**.

First, measure sloping distance ** AB. ** From observer point

**, measure vertical angles**

*A*_{1}**and**

*α***. From observer point**

*δ***, measure vertical angle**

*B*_{1}**.**

*β*In triangle A_{1}ΟB_{1},

Then calculate sloping distance ** A_{1}O**:

Finally, calculate height of object above ground at station ** A**: