Angle

In mensuration, three angles are important:

• Elevation angle
  Specifying the elevation of a distance
• Azimuth or direction angle
  Angle that is constructed by a distance and a defined direction (in geodesy mostly a north direction)
• Angle of refraction
  Angle constructed by two distances

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  Elevation angle (with Zenith-, Nadir- and angle of inclination)

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  Azimuth/direction angle

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  Angle of refraction