15.1 Types of Aerial Photograph There are three main types of aerial photograph:
• A vertical photograph is taken when the camera is pointing directly downwards on the area that is being photographed. Only the roofs of buildings are visible, along with roads and fields. All buildings are of the same scale, which is known as a true scale.
• A high oblique photograph is taken when the camera is pointing at an angle of 60° from the ground. As a result, the sides of buildings are also visible. High oblique photographs cover a much larger area than vertical photographs. Objects at the front of a high oblique photograph look larger than objects at the back of the photograph. This means that the scale is not true on high oblique photographs. Some of the horizon is visible in the background of a high oblique photograph.
• A low oblique photograph is taken when the camera is pointing at an angle of 30° from the ground. Low oblique photographs cover a much smaller area than high oblique photographs. As with all oblique photographs, low oblique photographs do not have a true scale.
: Fig. 15.1 A vertical aerial photograph
: Fig. 15.2 A high oblique aerial photograph Vertical
Lens of camera
Low oblique
High oblique
: Fig. 15.3 A low oblique aerial photograph
: Fig. 15.4 The position of the camera for each type of aerial photograph
GEOGRAPHICAL SKILLS 285
In 2007,Note!
the Chief
Examiner’s report stated that students struggled with aerial photograph
sketches. The 2012 Chief Examiner’s report found that, while the quality of sketches had improved, mistakes such as the following still existed:
• Sketches were out of proportion
• Items were not labelled
• Students sketched the OS map instead of the aerial photograph
