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Table of Contents
Foreword
Preface
Glossary

Chapter 1: Introduction

1.13: Air Photo Interpretation Criteria Applied to an Area at the Forks in Winnipeg

This very large-scale (1:5000) photo of the junction of the Red River 1 and the Assiniboine River 2 was taken at an early stage of redevelopment of “the Forks.” Some early construction can be seen at three locations north of the junction 3. The main Canadian National (CN) lines 4 with Union Station 5 can be seen in the north, and to the east 6 are the CN rail yards—now gone. Two railway bridges 7 cross the Assiniboine River, and west of them is the Bridge of the Old Forts—a road bridge 8.

The photograph illustrates the use of the criteria—tone, shape (shadow), size, and location—in identification of objects. The tone of the Red River is light 9 compared with the Assiniboine 10; the junction of the two is easily seen 11. The Red carries more suspended sediment than the Assiniboine. Individual branches in the shadows of trees on the southeast bank of the Red River 12 indicate that at the time they were leafless, and based on the umbrella shape of some of the shadows, the trees are probably elms. A few ornamental coniferous trees 13 can be seen in Bonnycastle Park 14 north of the Assiniboine, identification being on the basis of the triangular shadow shapes. Also, using the criterion of shape; the rounded roof form of a building in the southwest corner 15 is typical of indoor sports facilities, in this case a curling club. Shadow length gives an idea of the relative heights of objects; for example, at the Forks building 16 is higher than building 17, and, on the St. Boniface side of the river, building 18 is the tallest of all. If the actual height of one object is known, the heights of other objects can be determined from their shadows on a ratio basis. Finally, the criterion of location suggests that objects on the southern approaches to the Norwood Bridge 19 are buses, trucks, and cars, buses being the largest 20, trucks next 21 and cars the smallest 22.

Figure 1.13: Air Photo Interpretation Criteria Applied to an Area at the Forks in Winnipeg

Figure 1.13: Air Photo Interpretation Criteria Applied to an Area at the Forks in Winnipeg

Figure 1.13

Vertical air photo: AS88013-43

Flight height: 3,250 feet a.s.l; lens focal length: 152.03 mm.

Scale: 1:5,000 (approx.)

Date: April 24, 1988

Location: Latitude: 49º 53'N Longitude: 97º 07'W

Map sheets: 1:250,000 62H Winnipeg

1:50,000 62H/14 Winnipeg