@article{fdi:010077461,
  title = {{TERRA} : {T}errain {E}xtraction from elevation {R}asters through {R}epetitive {A}nisotropic filtering},
  author = {{P}ijl, {A}. and {B}ailly, {J}. {S}. and {F}eurer, {D}enis and {E}l {M}aaoui, {M}. {A}. and {B}oussema, {M}. {R}. and {T}arolli, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{O}ver the past decades, several filters have been developed to derive a {D}igital {T}errain {M}odel ({DTM}) from a {D}igital {S}urface {M}odel ({DSM}), by means of filtering out aboveground objects such as vegetation. {I}n this filtering process, however, one of the major challenges remains to precisely distinguish sharp terrain features, e.g. ridges, agricultural terraces or other anthropogenic geomorphology such as open-pit mines, riverbanks or road ramps. {H}ence, loss of elevation data around terrain edges (and consequent smoothing) is very common with existing algorithms. {I}n terraced landscapes, the preservation of precise geomorphology is of key importance in digital terrain analyses, such as hydrologic and erosion modelling, or automatic feature recognition and inventorying. {I}n this work, we propose a new filtering method called {TERRA} ({T}errain {E}xtraction from elevation {R}asters through {R}epetitive {A}nisotropic filtering). {T}he novelty of the algorithm lies within its usage of terrain aspect to guide the anisotropic filtering direction, therefore maximising the preservation of terrain edges. {W}e derived six {DTM}s from {DSM}s using {UAV} {S}tructure from {M}otion ({S}f{M}) photogrammetry, laser altimetry and satellite sources (grid resolutions ranging from 0.1-1.0 m). {T}he results indicated a close agreement of {DTM}s filtered using the {TERRA} algorithm and reference {DTM}s, while terrace risers were well preserved even under thick canopies of vines and trees. {C}ompared to existing filtering approaches, {TERRA} performed well in minimising {T}ype {I} errors (false ground removal), while {T}ype {II} errors occurred locally where vegetation was covering the terrace edges. {G}iven the promising filtering performance, and supported by the minimal requirements of parameterisation and computation, the {TERRA} algorithm could be a useful tool in {DTM} preparation for digital terrain analysis of agricultural terraces and similar hillslopes characterised by a complex mosaic of sharp terrain and non-terrain features.},
  keywords = {{D}igital {T}errain {M}odel ({DTM}) extraction ; {T}erraces ; {A}nisotropic filtering ; {V}egetation removal ; {E}dge preservation},
  booktitle = {},
  journal = {{I}nternational {J}ournal of {A}pplied {E}arth {O}bservation and {G}eoinformation},
  volume = {84},
  numero = {},
  pages = {art. 101977 [10 ]},
  ISSN = {0303-2434},
  year = {2020},
  DOI = {10.1016/j.jag.2019.101977},
  URL = {https://www.documentation.ird.fr/hor/fdi:010077461},
}