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Auteur Nikolaos Galiatsatos |
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The effect of leaf-on and leaf-off forest canopy conditions on LiDAR derived estimations of forest structural diversity / Sophie Davison in International journal of applied Earth observation and geoinformation, vol 92 (October 2020)
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Titre : The effect of leaf-on and leaf-off forest canopy conditions on LiDAR derived estimations of forest structural diversity Type de document : Article/Communication Auteurs : Sophie Davison, Auteur ; Daniel N.M. Donoghue, Auteur ; Nikolaos Galiatsatos, Auteur Année de publication : 2020 Article en page(s) : n° 102160 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] canopée
[Termes IGN] couvert forestier
[Termes IGN] diamètre à hauteur de poitrine
[Termes IGN] données lidar
[Termes IGN] hauteur des arbres
[Termes IGN] indicateur de biodiversité
[Termes IGN] modèle numérique de surface de la canopée
[Termes IGN] peuplement forestier
[Termes IGN] semis de points
[Termes IGN] structure de la végétationRésumé : (auteur) Forest structural diversity metrics describing diversity in tree size and crown shape within forest stands can be used as indicators of biodiversity. These diversity metrics can be generated using airborne laser scanning (LiDAR) data to provide a rapid and cost effective alternative to ground-based inspection. Measures of tree height derived from LiDAR can be significantly affected by the canopy conditions at the time of data collection, in particular whether the canopy is under leaf-on or leaf-off conditions, but there have been no studies of the effects on structural diversity metrics. The aim of this research is to assess whether leaf-on/leaf-off changes in canopy conditions during LiDAR data collection affect the accuracy of calculated forest structural diversity metrics. We undertook a quantitative analysis of LiDAR ground detection and return height, and return height diversity from two airborne laser scanning surveys collected under leaf-on and leaf-off conditions to assess initial dataset differences. LiDAR data were then regressed against field-derived tree size diversity measurements using diversity metrics from each LiDAR dataset in isolation and, where appropriate, a mixture of the two. Models utilising leaf-off LiDAR diversity variables described DBH diversity, crown length diversity and crown width diversity more successfully than leaf-on (leaf-on models resulted in R² values of 0.66, 0.38 and 0.16, respectively, and leaf-off models 0.67, 0.37 and 0.23, respectively). When LiDAR datasets were combined into one model to describe tree height diversity and DBH diversity the models described 75% and 69% of the variance (R² of 0.75 for tree height diversity and 0.69 for DBH diversity). The results suggest that tree height diversity models derived from airborne LiDAR, collected (and where appropriate combined) under any seasonal conditions, can be used to differentiate between simple single and diverse multiple storey forest structure with confidence. Numéro de notice : A2020-749 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.jag.2020.102160 Date de publication en ligne : 09/06/2020 En ligne : https://doi.org/10.1016/j.jag.2020.102160 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96399
in International journal of applied Earth observation and geoinformation > vol 92 (October 2020) . - n° 102160[article]High resolution elevation data derived from stereoscopic CORONA imagery ground control: an approach using IKONOS and SRTM data / Nikolaos Galiatsatos in Photogrammetric Engineering & Remote Sensing, PERS, vol 74 n° 9 (September 2008)
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Titre : High resolution elevation data derived from stereoscopic CORONA imagery ground control: an approach using IKONOS and SRTM data Type de document : Article/Communication Auteurs : Nikolaos Galiatsatos, Auteur ; N.M. Donoghue, Auteur ; G. Philip, Auteur Année de publication : 2008 Article en page(s) : pp 1093 - 1106 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] contour
[Termes IGN] correction géométrique
[Termes IGN] distorsion d'image
[Termes IGN] estimation de précision
[Termes IGN] géométrie de l'image
[Termes IGN] image Corona
[Termes IGN] image Ikonos
[Termes IGN] image SRTM
[Termes IGN] MNS SRTM
[Termes IGN] modèle numérique de surface
[Termes IGN] modèle stéréoscopique
[Termes IGN] radargrammétrie
[Termes IGN] SyrieRésumé : (Auteur) The first space mission to provide stereoscopic imagery of the Earth’s surface was from the American CORONA spy satellite program from which it is possible to generate Digital Elevation Models (DEMs). CORONA imagery and derived DEMs are of most value in areas where conventional topographic maps are of poor quality, but the problem has been that until recently, it was difficult to assess their accuracy. This paper presents a methodology to create a high quality DEM from CORONA imagery using horizontal ground control derived from Ikonos space imagery and vertical ground control from map-based contour lines. Such DEMs can be produced without the need for field-based ground control measurements which is an advantage in many parts of world where ground surveying is difficult. Knowledge of CORONA image distortions, satellite geometry, ground resolution, and film scanning are important factors that can affect the DEM extraction process. A study area in Syria is used to demonstrate the method, and Shuttle Radar Topography Mission (SRTM) data is used to perform quantitative and qualitative accuracy assessment of the automatically extracted DEM. The SRTM data has enormous importance for validating the quality of CORONA DEMs, and so, unlocking the potential of a largely untapped part of the archive. We conclude that CORONA data can produce unbiased, high-resolution DEM data which may be valuable for researchers working in countries where topographic data is difficult to obtain. Copyright ASPRS Numéro de notice : A2008-346 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.74.9.1093 En ligne : https://doi.org/10.14358/PERS.74.9.1093 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29339
in Photogrammetric Engineering & Remote Sensing, PERS > vol 74 n° 9 (September 2008) . - pp 1093 - 1106[article]