With regard to Trigonometric Levelling, which one of the following statements is correct at its simplest applications?
1
Determination of the elevation of stations is based on the observed vertical angles and the horizontal distances
2
Determination of the horizontal distances is based on the observed vertical angles
3
Determination of the vertical angles is based on the observed horizontal distances
4
Determination of the horizontal distances is based on the observed vertical angles and the measured elevations