Skylab image using a long focal length “earth terrain” camera.
Scale: 1:435,000 (approx.)
Date: September 19, 1973
Location: The point X on the photo is 98ºW, 49ºN
Map sheets: (for
This Skylab[i] photo shows land on either side of the Canada/U.S.A. border 1. This is a true photograph as opposed to the image that appears in figure 14.1. The photograph shows real colours, although they are distorted by the fact that the earth’s surface is being viewed through the whole atmosphere. Within
At the date the photo was taken (September 19) the grain harvest was partly completed resulting in beige coloured fields 4—on which there was still some vegetation—to dark-toned fields 5 where the chernozemic soils were exposed. Most of the area is devoted to agriculture with individual rectangular fields being visible 6, but some areas of dark-toned natural vegetation remain: along the eastern edge of the Pembina Hills 7 with some Lake Agassiz strandlines clearly visible 8; along the sides of the Pembina Valley 9 and Lyles Creek 10 further north; in the area around Lizard Lake 11; and in the Roseau River Anishinabe First Nation 12.
Some variations are visible within the agricultural area; for example, the area south and west of the Pembina Escarpment 13 is lighter-toned than the land. further east 14, suggesting that there is more grain or stubble left in the fields in the west. Also, there is a darker area in the centre of the photo where fields are smaller 15.
Small tufts of clouds can be seen 16 that throw shadows to the northeast 17, indicating that the photo was taken in mid-afternoon when the sun was in the southwest.
[i] “In 1973, Skylab, the first American space workshop, was launched and its astronauts took over 35,000 images of the earth with the Earth Resources Experiment Package (EREP) on board. The EREP included a six-camera multi-spectral array, a long focal length “earth terrain” camera, a 13-channel multi-spectral scanner, a pointable spectroradiometer, and two microwave systems. The EREP experiments were the first to demonstrate the complementary nature of photography and electronic imaging from space.” Lillesand, T.L. and Kiefer, R.W. Remote Sensing and Image Interpretation (Third Edition)