DEM Production of Wolfville Harbour
Yuna Jiao, while as a student at the Centre of Geographic Sciences (COGS), acquired and processed oblique aerial photographs of the harbour in Wolfville, Nova Scotia to create a Digital Elevation Model (DEM) of the mudflats during low-tide.
Ground control points were collected along the coastline using a Trimble Geo XT GPS (WAAS enabled) system and used to establish absolute orientation of the aerial photographs.
Several hundred 3D points were manually collected by identifying features such as rocks and small tributaries within the various photographs. Although somewhat tedious, the point collection process was performed in about a day and a half.
A Triangulated Irregular Network (TIN) of the points was then generated and compared with one generated from LiDAR (Light Detection and Ranging, an expensive, but high accuracy laser ranging system). It was found that 85% of the points collected using ObliqueMapper was within 0.5 metres of the elevations determined by the LiDAR system.
