Aerial Survey - Terms Used in Aerial Survey

Terms Used in Aerial Survey

• exposure station or air station

  the position of the optical centre of the camera at the moment of exposure.

• flying height

  the eleveation of the exposure station above the datum (usually mean sea level).

• altitude

  the vertical distance of the aircraft above the earth surface.

• tilt

  the angle between the aerial camera and the line of flight.

• tip

  the angle between the aerial camera and the horizontal axis perpendicular to the line of flight.

• principal point

  the point of intersection of the optical axis of the areal camera with the photographical plane

• isocentre

  the point on the areal photograph in which the bisector of the angle of tilt meets the photograph.

• nadir point

  the image of the nadir, i.e. the point on the areal photograph where a plumbline dropped from the front nodal point pierces the photograph.

• scale

  ratio of the focal length of the camera objective and the distance of the exposure station from the ground

Aerial surveys are used for:

• Archaeology
• Fishery surveys
• Hydrocarbon exploration
• Land survey
• Mining
• Monitoring wildlife and insect populations, called aerial census or sampling.
• Monitoring vegetation and ground cover
• Reconnaissance
• Used in Transportation Projects in conjunction with Ground Surveys(Roadway, Bridge, Interstate)

Aerial survey uses a measuring camera where the elements of the interior orientation are known, but a camera that has much larger focal length and film and more lenses are used.