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\newblock Representation and visualization of terrain surfaces at variable
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\newblock In {\em Proceedings Scientific Visualization '95}, pages 50--68.
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\bibitem[\protect\citeauthoryear{Cole and Sharir} {1989}]{ColSha89}
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\newblock Visibility problems for polyhedral terrains.
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\newblock On levels of detail in terrains.
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\bibitem[\protect\citeauthoryear{de Berg and van Kreveld}{1997}]{BerKre97}
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\newblock Trekking in the alps without freezing or getting tired.
\newblock {\em Algorithmica}, 18:306--323, 1997.

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\newblock Visibility algorithms on triangulated terrain models.
\newblock {\em International Journal of Geographic Information Systems},
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\bibitem[\protect\citeauthoryear{De Floriani and Magillo}{1995}]{DeFMagCOSIT95}
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\newblock Updating visibility information on multiresolution terrain models.
\newblock In W.~Kuhn A.U.~Frank, editor, {\em Spatial Information Theory - A
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\bibitem[\protect\citeauthoryear{De Floriani et al.}{1997}]{DeFMagPupIEEE97}
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\newblock Building and traversing a surface at Variable Resolution.
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\bibitem[\protect\citeauthoryear{De Floriani et al.}{1998}]{DeFMagPupIEEE98}
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\newblock Efficient implementation of multi-triangulations.
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\bibitem[\protect\citeauthoryear{Dobrindt and Yvinec}{1993}]{DobYvi93}
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\newblock Remembering conflicts in history yields dynamic algorithms.
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\newblock Encoding ad validating data from maps and images.
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\bibitem[\protect\citeauthoryear{Felleman and Griffin}{1990}]{FelGri90}
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\newblock software package developed by G.~Loercher, T.~Huetter.
\newblock Technical report, Institute for Computer Graphics WSI/GRIS,
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\bibitem[\protect\citeauthoryear{Fowler and Little}{1979}]{FowLit79}
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\newblock Automatic extraction of irregular network digital terrain models.
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\newblock Triangular irregular networks to approximate digital terrains.
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\newblock Fast polygonal approximation of terrains and height fields.
\newblock Technical Report CMU-CS-95-181, School of Computer Sciences, Carnegie
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\bibitem[\protect\citeauthoryear{Garland and Heckbert}{1997}]{GarHec97}
M.~Garland and P.S. Heckbert.
\newblock Surface simplification using quadric error metrics.
\newblock Comp. Graph. Proc., Annual Conf. Series (Siggraph '97),
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\newblock Progressive meshes.
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\bibitem[\protect\citeauthoryear{Hoppe}{1998}]{Hop98}
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\newblock Smooth view-dependent level-of-detail control and its application to
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\newblock In {\em Proceedings IEEE Visualization'98}, pages 35--42, Research
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\bibitem[\protect\citeauthoryear{Lanthier et al.}{1997}]{LanMahSac97}
M.~Lanthier, A.~Maheshwari, and J.R. Sack.
\newblock Approximating weighted shortest paths on polyhedral surfaces.
\newblock In {\em Proceedings ACM Symposium on Computational Geometry}, Nice,
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\bibitem[\protect\citeauthoryear{Lee}{1989}]{Lee89}
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\newblock A drop heuristic conversion method for extracting irregular networks
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\newblock In {\em Proceedings GIS/LIS'89}, pages 30--39, Orlando, FL, USA,
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\bibitem[\protect\citeauthoryear{Lindstrom et al.}{1996}]{LinAl96}
P.~Lindstrom, D.~Koller, W.~Ribarsky, L.F. Hodges, N.~Faust, and G.A. Turner.
\newblock Real-time, continuous level of detail rendering of height fields.
\newblock In {\em Comp. Graph. Proc., Annual Conf. Series (SIGGRAPH '96), ACM
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\bibitem[\protect\citeauthoryear{Magillo}{1999}]{Mag99}
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\newblock {\em Spatial Operations on Multiresolution Cell Complexes}.
\newblock PhD thesis, Dept. of Computer and Information Sciences, University of
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\bibitem[\protect\citeauthoryear{Puppo}{1996}]{Pup96}
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\newblock Variable resolution terrain surfaces.
\newblock In {\em Proceedings Eight Canadian Conference on Computational
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\newblock Extended version appeared under the title "Variable resolution
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\bibitem[\protect\citeauthoryear{Renka and Cline}{1984}]{RenCli84}
R.J.~Renka and A.K.~Cline.
\newblock A triangle-based $C^1$ interpolation method.
\newblock {\em Rocky Mountain Journal of Mathematics},
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\bibitem[\protect\citeauthoryear{Rippa}{1992}]{Rip92}
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\newblock Adaptive approximations by piecewise linear polynomials on
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\newblock {\em SIAM Journal on Scientific and Statistic Computing},
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\bibitem[\protect\citeauthoryear{Topovista}{????}]{Topovista}
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\newblock software package developed by w. evans, g. townsend.
\newblock Technical report, Computer Sciance Department, University of Arizona,
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\newblock http:// www.cs.arizona.edu/ topovista/ index.html.

\bibitem[\protect\citeauthoryear{van Kreveld}{1994}]{Kre94PATH}
M.~van Kreveld.
\newblock On quality paths on polyhedral terrains.
\newblock In J.~Nievergelt, H.J. Roos, T. amd~Schack, and P.~Widmayer, editors,
  {\em Lecture Notes in Computer Science}, volume 884, pages 113--122.
  Springer-Verlag, 1994.
\newblock Proceedings IGIS'94: Geographic Information Systems.

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