| The last step and one of the most critical is a comprehensive accuracy assessment. This is presently being developed and will be reported at a later date. To obtain reference data, aerial videography was used. Aerial videography involves attaching two 8mm video cameras on to a fixed wing airplane. Video tapes are synchronized with a GPS receiver. The GPS points are differentially-corrected to provide greater spatial point accuracy. Some of the benefits of videography used in this framework include: a large number of stratified points, completely independent referenced data, and lower cost per point than conventional methods. One drawback was that the motion of the plane (pitch and yaw) added a degree of uncertainty between where the GPS point occurs and where the cameras were pointing. This was solved by aggregating the pixel size up from 30m to 90m (.81 ha). It was felt that even at a 1 ha minimum mapping unit, this map would continue to be applicable to site-specific resource problems.
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