multiviewshed

Multiviewshed is a concept in geographic information systems (GIS) that extends traditional viewshed analysis by considering visibility from multiple observer locations rather than a single vantage point. It aims to assess how well an area is covered in terms of line-of-sight from a set of designated viewpoints, enabling the evaluation of overall visibility, redundancy, and gaps across a landscape.

Computationally, multiviewshed typically uses a digital elevation model (DEM) together with coordinates and heights for each observer. Individual viewsheds are generated for each location using ray casting or horizon-based algorithms, and the results are then combined through logical operations or statistical summaries to produce a composite representation. Outputs can be raster or vector, showing areas visible from at least one observer, from all observers, or with weighted visibility according to observer importance. Time and thematic factors can be incorporated to create dynamic or multi-criteria multiviewshed analyses.

Common applications include telecommunications and infrastructure planning (to optimize tower placement and coverage), security and defense (to map surveillance visibility), environmental monitoring, landscape and urban planning, and tourism or hazard mitigation where multiple vantage points are relevant. The approach helps researchers and planners understand coverage patterns, identify blind spots, and compare scenarios.

Key considerations for multiviewshed analysis are the resolution and quality of the DEM, the assumed observer height and occluding vegetation, and computational demands for large study areas. Limitations include dynamic vegetation, atmospheric effects, and changes over time that may not be captured in a static model. Related concepts include viewshed analysis, line-of-sight, and visibility analysis.