Digital terrain models (DTMs) are considered important basic geographic data. They are widely used in the fields of cartography, land utilization, urban planning, communications, and remote sensing. Digital photogrammetry mainly based on stereo image matching is a frequently applied technique to generate DTMs. Generally, the process of ground filtering should be applied to the point cloud deriv...

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A multilevel tabulated interaction method (TIM) is described for application to the analysis of exceptionally large two-dimensional (2-D) UHF terrain propagation problems. While standard TIM schemes offer extremely rapid solutions to terrain propagation problems on a medium to large scale ( 20 km), the computation times increase quadratically with problem size. For problems of extremely large s...

Queries over streaming data offer the potential to provide timely information for modern database applications, such as sensor networks and web services. Isoline-based visualization of streaming data has the potential to be of great use in such applications. Dynamic (real-time) isoline extraction from the streaming data is needed in order to fully harvest that potential, allowing the users to s...

A path from s to t on a polyhedral terrain is descending if the height of a point p never increases while we move p along the path from s to t. No efficient algorithm is known to find a shortest descending path from s to t in a polyhedral terrain. We give some properties of such paths. In the case where the face sequence is specified, we show that the shortest descending path is unique, and giv...

Mesh-based terrain representations provide accurate descriptions of a terrain, but fail in capturing its morphological structure. The morphology of a terrain is defined by its critical points and by the critical lines joining them, which form a so-called surface network. Because of the large size of current terrain data sets, a multi-resolution representation of the terrain morphology is crucia...

The design of an electrically actuated robot with one articulated leg is presented, as well as simulation results of its control algorithm. The algorithm enables the robot, whose name is OLIE (One Leg Is Enough), to control simultaneously its forward velocity during flight, its hopping height, the placement of its foot on desired footholds, the orientation of its body and its angular momentum, ...