tailieunhanh - Báo cáo " Research on the optimal picket sampling interval in automated digital terrain model creation by using digital photogrammetry "

In the method of creating digital terrain model (DTM) by using digital photogrammetry, the picket sampling interval (PSI) plays an important role since it strongly influences on the production effectiveness and on the accuracy of created DTMs. The optimal value of PSI must be balanced between requirements of effectiveness and of accuracy. This research is focused on the influence of PSI on root mean square error (RMSE) of created DTM and on the number of error pickets (caused by limitation of image matching technique) that must be checked and corrected manually. Based on the results obtained in four. | VNU Journal of Science Earth Sciences 23 2007 96-104 Research on the optimal picket sampling interval in automated digital terrain model creation by using digital photogrammetry Tran Quoc Binh College of Science VNU Received 24 February 2007 Abstract. In the method of creating digital terrain model DTM by using digital photogrammetry the picket sampling interval PSI plays an important role since it strongly influences on the production effectiveness and on the accuracy of created DTMs. The optimal value of PSI must be balanced between requirements of effectiveness and of accuracy. This research is focused on the influence of PSI on root mean square error RMSE of created DTM and on the number of error pickets caused by limitation of image matching technique that must be checked and corrected manually. Based on the results obtained in four experimental areas of Vietnam Co Loa Duong Lam Ba Vi and Lang Son the paper has proposed an empirical equation for choosing optimal PSI PSI ky pXMa where P is the scan resolution gm Ma is the denominator of airphoto scale k is a coefficient depending on the characteristics of topography. Keywords Digital terrain model DTM Picket sampling interval Digital photogrammetry DTM accuracy. 1. Introduction Being known from 1950s the Digital Terrain Models DTM as well as the Digital Elevation Models DEM are getting more and more popular. Nowadays DTM becomes an important component of spatial data infrastructure SDI and to the creation of DTMs a special attention is given. At present time among available methods for creating DTMs the method using airphoto and applying digital photogrammetry is the most popular one 1 . In DTM creation using Tel. 84-4-8581420. E-mail tqbinh@ digital photogrammetry the key steps are placing a grid of pickets over the interested area and measuring these pickets automatically by using image matching technique. Since the image matching technique is still imperfect 2 3 the choice of picket sampling .