The use of LANDSAT imagery to locate uncharted coastal features on the Labrador coast

A survey of several offshore islands, rocks and shoals on the Labrador Coast was performed, using LANDSAT imagery to assist in the location of uncharted hydrographic features. Several satellite coverages of the coast were studied prior to the survey, and suspected shoal points identified. Using map-derived control points and monocomparator measurements of the LANDSAT images, the positions of these points were determined by mathematical adjustment to an estimated position accuracy of 150 meters. As a result, on the survey, an uncharted island and eight uncharted drying rocks, which might easily have escaped detection from a survey ship, were verified and positioned. To check the accuracy of the coordinates derived from LANDSAT, three islands were positioned by standard ground survey methods. The positional differences, all less than 150 meters, are not plottable at the scale of the existing offshore charts. The LANDSAT positions were also used to control aerial photography of a shoal area for office compilation of a hydrographic chart.