authority: folia
slug: viewshed
name: Viewshed
domain: land
subdomain: topography
authority_id: folia:viewshed
parent: elevation
external_ids:
  cf_standard_name: null
canonical_units: categorical
external_validations:
  gdal:
    tool: gdal_viewshed
    algorithm: viewshed
    docs_url: https://gdal.org/programs/gdal_viewshed.html
  library:
    name: whitebox-tools
    id: Viewshed
    docs_url: https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#Viewshed
description: |
  Binary or multi-observer visibility raster derived from a DEM and one
  or more observer points. For a single observer the output is binary
  (1 = visible, 0 = not visible, nodata = outside analysis area); for
  multiple observers it is typically categorical, encoding how many
  observers see each pixel. Line-of-sight is computed by ray-tracing
  from observer to target across DEM cells, with optional corrections
  for earth curvature and atmospheric refraction. Used by
  line-of-sight analysis, telecommunications and radar siting,
  wildlife habitat sightline modelling, and scenic / recreation
  planning ops.
theme: terrain
consumed_by: []
produced_by:
  - terrain_viewshed
demos: []
status: documented
example_recipes:
  - title: "Single-observer binary viewshed from a DEM (GDAL CLI)"
    tool: gdal
    requires: [elevation]
    command: |
      gdal_viewshed -ox -111.5 -oy 40.5 -oz 1.7 -tz 0.0 \
        -md 10000 -cc 0.85714 \
        dem.tif viewshed.tif
    docs_url: https://gdal.org/programs/gdal_viewshed.html
  - title: "Single-observer viewshed (WhiteboxTools)"
    tool: rust
    requires: [elevation]
    command: |
      whitebox_tools --run=Viewshed \
        --dem=dem.tif --stations=observers.shp \
        --output=viewshed.tif --height=1.7
    docs_url: https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#Viewshed
sources:
  - https://gdal.org/programs/gdal_viewshed.html
  - https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#Viewshed
  - Wang, J., Robinson, G.J., White, K. 2000, Generating viewsheds without using sightlines, Photogrammetric Engineering & Remote Sensing 66(1), 87-90