Orthographical Rectification Technology for Aerial Images in Forest Management Inventory in Wenling City

Aerial images are important fundamental materials for forest management inventory. However, they easily produce distortion under influences of topographic and the other factors. Therefore, it′s necessary to conduct orthorectification before using them to eliminate distortion. The study based on the information gained by UltraCamX digital aerophotographic camera, set up corresponding parameters in LPS project, read in exterior orientation elements carried by data, directly set triangulation escaping from troublesome calculation process. The positional precision of orthophoto, with reference to topographic maps, was analyzed. And the result showed, LPS could support orthorectification of digital aerophotographic image, the processed image was relatively ideal with good matching and high positioning accuracy. The error was calculated by the corresponding coordinates of topographic maps and images from the checkpoint and the average overall error was only 1.249 m, which could met the needs of forest management inventory in Wenling. The method has great significance in practical application for it could solve the problems of large amount of digital aerophotographic images, long processing time, and the use of DEM, etc.