@TechReport{	  Gerstner:2003*2,
  author	= {Gerstner, T.},
  title		= {Top-Down View-Dependent Terrain Triangulation
		  using the Octagon Metric},
  institution	= {Institut f\"ur Angewante Mathematik},
  pdf		= {http://wissrech.ins.uni-bonn.de/research/pub/gerstner/topdown.pdf}
		  ,
  abstract	= { In this paper, we introduce the octagon metric as a
		  universal distance metric for the interactive visualization
		  of large-scale terrain data. Based on recursive bisection
		  triangle meshes, this metric automatically ensures valid
		  triangular meshes without cracks or T-junctions. We will
		  show how the octagon metric can be used for view-dependent
		  refinement at little computational cost and with no
		  additional storage requirements. It can easily be combined
		  with a suitable geometric error metric to extract and
		  render adaptive view-dependent terrain meshes in an
		  output-sensitive way. We will show the performance of the
		  whole system, which is straightforward to implement, in
		  several examples. },
  year		= {2003},
  annote	= {report}
}