authority: folia
slug: tri
name: Terrain Ruggedness Index
domain: land
subdomain: topography
authority_id: folia:tri
parent: elevation
aliases:
  - terrain-ruggedness-index
external_ids:
  cf_standard_name: null
canonical_units: m
external_validations:
  gdal:
    tool: gdaldem
    algorithm: TRI
    docs_url: https://gdal.org/programs/gdaldem.html#terrain-ruggedness-index-tri
  library:
    name: whitebox-tools
    id: RuggednessIndex
    docs_url: https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#RuggednessIndex
description: |
  Mean absolute difference in elevation between a pixel and its
  immediate neighbours, expressed in meters. Originally developed
  by Riley et al. (1999) to quantify topographic heterogeneity in
  habitat-suitability models for bighorn sheep. Used by habitat
  modelling, accessibility, and military mobility ops.
theme: terrain
consumed_by: []
produced_by:
  - terrain_tri
demos: []
status: documented
sources:
  - https://gdal.org/programs/gdaldem.html#terrain-ruggedness-index-tri
  - Riley, S.J., DeGloria, S.D., and Elliot, R. 1999, Intermountain Journal of Sciences 5, 23-27