CARTOGRAPHY REPORT

As no triangulation surveying was done this season, due to a planned coverage of the area with vertical aerial photographs which did not eventuate, the only materials available for plotting a base map were United States Navy aerial oblique photographs. Several standard methods of plotting from oblique photographs were tried but could not be used because of the lack of ground control. Eventually a plotting method using a peak of approximate known height and distance from the camera (to determine the horizontal plane in the photograph and which was used as a reference plane) was evolved.

This method enabled an accurate base map to be plotted. This process took most of the first term with Willis and Cooper working on the basic plotting full-time. Accuracy was necessary to show on the map the complexities of the metamorphic rocks which comprise the Koettlitz area. Several runs of vertical photographs have turned up since the map was plotted and a comparison of these and the map led to a few minor alterations in ridge lines, shapes of glaciers, etc. but has proved the overall accuracy to be comparable with that of the normal practice of plotting from verticals (a slower, more elaborate method).

Thanks are due to Dr. Wellman, Geology Department, Victoria University of Wellington, for his guidance in working out the method of plotting used, and to Cartographic Division, Lands and Survey Department, for lending aerial photographs.