Overhangs have been a major stumbling block in the context of terrain synthesis models. These models resort invariably to a heightfield paradigm, which immediately precludes the existence of any type of overhang. This article presents a new technique for the generation of surfaces, with the ability to model overhangs in a procedural way. This technique can be used generally to model landscape e...

The direction and speed of winds play an important role in the occurrence of pollutions and dust stormas well as location placement for the establishment of industries and the expansion of cities. Yazd is a dry area of Iran, and constantly exposed to the dust particles in the air; and this in terms of human life and health issues are of special importance. In this paper a day when due to the am...

The direction and speed of winds play an important role in the occurrence of pollutions and dust stormas well as location placement for the establishment of industries and the expansion of cities. Yazd is a dry area of Iran, and constantly exposed to the dust particles in the air; and this in terms of human life and health issues are of special importance. In this paper a day when due to the am...

Given a simple polygon P with n vertices, the visibility polygon (VP) of a point q (VP(q)), or a segment pq (VP(pq)) inside P can be computed in linear time. We propose a linear time algorithm to extend VP of a viewer (point or segment), by converting some edges of P into mirrors, such that a given non-visible segment uw can also be seen from the viewer. Various definitions for the visibility o...

We show that the segment endpoint visibility graph of any finite set of 2n line segments contains a planar matching that does not use any segment edge, if the line segments in our set are convexly independent.

The steep topography of mountain landscapes arises from interactions among tectonic rock uplift, valley incision and landslide erosion on hillslopes. Hillslopes in rapidly uplifting landscapes are thought to respond to river incision into bedrock by steepening to a maximum stable or ‘threshold’ angle1–3. Landslide erosion rates are predicted to increase nonlinearly as hillslope angles approach ...