The Accuracy of Differential Monorestitution Relative to Conventional Data Transfer Methods for Aerial Photographs

Forest maps are still today being constructed predominantly by transferring information from aerial photographs to maps using relatively imprecise manual tools such as a Sketchmaster. (Another name for this or a similar apparatus is a Zoom Transfer Scope.) Such devices correct for as much photographic distortion as possible using relatively crude manual methods. New geomatics¹ technologies like differential monorestitution (DM) coupled with modern computing power provide an efficient alternative for this data transfer which has the potential to improve the quality of the final forest maps. But the question remains: what is the magnitude of the locational improvement possible with DM and how is it affected by different topography? A study was undertaken to answer this question. Comparisons between DM and conventional data transfer/mapping methods were conducted for forest maps on which three different types of topography were present. The results from each method were also compared to GPS points recorded along a road. Results suggest that DM provides a considerable improvement in accuracy over conventional methods for transferring information from aerial photographs to orthographic maps in forestry. Moreover, DM requires a comparable amount of operator time as conventional methods to obtain this improvement. North. J. Appl. For. 14(4):183-188.