About Air Photos

What is an aerial photograph?

An aerial photograph is a photographic image of a portion of the earth's surface taken with a camera mounted in a fixed-wing aircraft.

How much area does an aerial photograph cover?

The amount of area covered by a photograph depends on its scale, as the size of the photograph is constant. Individual photographs cover relatively small areas, ranging from 1.6 km x 1.6 km (1 mi. x 1 mi.) for very large scale photography (1:5 000), to 15 km x 15 km (9 mi. x 9 mi.) for small scale photography (1:60 000).

What is photograph scale?

The scale of a photograph, like that of a map, is the ratio of distance on the phot ograph to the corresponding distance on the ground.

So, for example, if the scale of a photograph is 1:30 000, this simply means that one unit of any measure (inches, cm, etc.) represents 30,000 units of the same measure on the ground.

All areas of the province are available at either medium or small scales, while large-scale photographs are available for limited areas.

Scale Metric (1cm =) Imperial (1 inch = approx.)
1:15 000 0.15 km approximately 1/4 mi.
1:20 000 0.20 km approximately 1/3 mi.
1:30 000 0.30 km approximately 1/2 mi.
1:40 000 0.40 km approximately 2/3 mi.
1:50 000 0.50 km approximately 3/4 mi.
1:60 000 0.60 km approximately 1 mi.

Do you need stereo coverage?

Stereo coverage aerial photography

Aerial photography is flown so each frame overlaps the previous frame by at least 60 percent. This overlapping area, although of the same portion of ground, has been photographed from two different angles, providing two different perspectives of that portion of ground. When adjacent photos are viewed through a stereoscope, the difference in perspective allows the viewer to see the image in three dimensions, or stereo. Generally, stereo pairs are purchased by engineering and resource professionals for mapping and interpretive purposes.

Do You Need Pictorial Coverage?

Pictoral coverage aerial photography

Pictorial coverage provides a complete overview of an area with minimal overlap between photographs by using alternate frames. The area cannot be viewed in stereo because of the lack of overlap between photographs. The majority of customers are interested in pictorial coverage.

Contacts

Comments regarding the Air Photo webpages may be directed to:

  • Syd Wood, Air Photo Distribution Technologist, Air Photo Services

 

Page Information

Updated: May 14, 2010