Vertical air photos record situations that exist at a specific time and are particularly useful in recording changes if a sequence of photos of the same area exists. Property boundaries are difficult to define if they fall along a naturally changing feature such as a river channel. Three examples illustrate the legal problems that can arise.
Rivers have traditionally been used as boundaries between various administrative units: municipalities, counties, provinces, states, and even countries. However, they are unsatisfactory administrative boundaries because they change position over time resulting in ownership disputes.
In Manitoba rivers were used to delimit several First Nations Reserves. Often the rivers used were meandering rivers. However, the development of meanders and cut offs is one of the faster geomorphological processes—fast enough to be recorded on sequential air photographs (photos taken of the same area over a period of years). Figures 19.1, 19.2, and 19.3 show roughly the same stretch of the Assiniboine River near its junction with Birdtail Creek—albeit at different scales—taken in 1945, 1956, and 1994 respectively.
Headingley Correctional Institute 1, opened in 1930, is the oldest of seven provincial correctional institutes in Manitoba. Its capacity is 485 minimum, medium, and maximum-security inmates, but that number is often exceeded. Following serious rioting in 1996, when the buildings were virtually destroyed, two new wings were constructed; possibly the two star-shaped buildings in the north 2. The jail is located near the western edge of the RM of Headingley on the north side of the eastward-flowing Assiniboine River 3. The approach road 4 leads to the Trans-Canada Highway just off the image to the north. The car park for employees and visitors is located in the northeast 5. Minimum-security inmates probably work dark-toned fields 6—fallow at the time the image was obtained.
Google Earth 2006 Digital Globe
Scale 1:5,000 (approx.)
Location: 49º 52'N: 97º 26' W
Map sheets: 1:250,000 62H Winnipeg
1:50,000 62H/14 Winnipeg