References

Conrad, 1993

Conrad, A. (1993). Software tracks terrain effects on transmitters. Microwaves & RF, 32:141. Product evaluation.

De Floriani et al., 1986

De Floriani, L., Falcidieno, B., Pienovi, C., Allen, D., and Nagy, G. (1986). A visibility-based model for terrain features. In Proceedings: Second International Symposium on Spatial Data Handling, pages 235--250. Seattle, Washington.

Fisher, 1992

Fisher, P. F. (1992). 1st experiments in viewshed uncertainty - simulating fuzzy viewsheds. Photogrammetric Engineering And Remote Sensing, 58:345--352.

Fisher, 1993

Fisher, P. F. (1993). Algorithm and implementation uncertainty in viewshed analysis. International Journal Of Geographical Information Systems, 7:331--347.

Gennery, 1989

Gennery, D. B. (1989). Visual terrain matching for a Mars rover. In IEEE Conf. on Vision and Pattern Recognition, pages 483--491, San Diego, CA, USA.

Lee, 1992

Lee, J. (1992). Visibility dominance and topographic features on digital elevation models. In Bresnahan, P., Corwin, E., and Cowen, D., editors, Proceedings 5th International Symposium on Spatial Data Handling, volume 2, pages 622--631. International Geographical Union, Commission on GIS, Humanities and Social Sciences Computing Lab, U. South Carolina, Columbia, South Carolina, USA.

Lee et al., 1993

Lee, J., Snyder, P. K., and Fisher, P. F. (1993). Modeling the effect of data errors on feature extraction from digital elevation models. Photogrammetric Engineering And Remote Sensing, 58:1461--1467.

Nagy, 1994

Nagy, G. (1994). Terrain visibility. Comput. & Graphics, 18(6).

Ray, 1994

Ray, C. K. (1994). Representing Visibility for Siting Problems. PhD thesis, Electrical, Computer, and Systems Engineering Dept., Rensselaer Polytechnic Institute.

Shannon and Ignizio, 1971

Shannon, R. E. and Ignizio, J. P. (1971). Minimum altitude visibility diagram --- MAVD. Simulation, pages 256--260.

Teng and Davis, 1992

Teng, Y. A. and Davis, L. S. (1992). Visibility analysis on digital terrain models and its parallel implementation. Technical Report CAR-TR-625, Center for Automation Research, University of Maryland, College Park, Maryland.

Wood and Fisher, 1993

Wood, J. D. and Fisher, P. F. (1993). Assessing interpolation accuracy in elevation models. IEEE Computer Graphics And Applications, 13:48--56.

  
Figure 1: N37E127 DTED Cell

  
Figure 2: (a) One Dimensional Visibility. (b) Two Dimensional Visibility Ring

  
Figure 3: Sample Adirondack Terrain for DEM/Xdraw

  
Figure 4: Three Different Approximate Viewsheds

  
Figure 5: Comparison of Visibility Index Calculated with 32 vs 128 Rays per Point, for Some Random Points

  
Figure 6: Best 12 Points, Selected Using 128 Rays vs 32 Rays

  
Figure 7: Visibility Index For Each Point

  
Figure 8: Histogram of Visibility Indices

  
Figure 9: Visibility Index vs Elevation of Some Random Points

  
Figure 10: Visibility vs Elevation of the Best Points

  
Figure 11: Screen from PC Demo Application