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Effects of numbers of observations and predictors for various model types on the performance of forest inventory with airborne laser scanning / Diogo N. Cosenza in Canadian Journal of Forest Research, Vol 52 n° 3 (March 2022)  

Public [article]  inCanadian Journal of Forest Research > Vol 52 n° 3 (March 2022) . - pp 385 - 395 Titre : Effects of numbers of observations and predictors for various model types on the performance of forest inventory with airborne laser scanning Type de document : Article/Communication Auteurs : Diogo N. Cosenza, Auteur ; Petteri Packalen, Auteur ; Matti Maltamo, Auteur ; Petri Varvia, Auteur ; Janne Raty, Auteur ; Paola Soares, Auteur ; Margarida Tomé, Auteur ; Jacob L. Strunk, Auteur ; Lauri Korhonen, Auteur Année de publication : 2022 Article en page(s) : pp 385 - 395 Note générale : bibliographie Langues : Français (fre) Anglais (eng) Descripteur : [Termes IGN] forêt boréale [Termes IGN] lasergrammétrie [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) Semi- and nonparametric models are popular in the area-based approach (ABA) using airborne laser scanning. It is unclear, however, how many predictors and training plots are needed to provide accurate predictions without overfitting. This work aims to explore these limits for various approaches: ordinary least squares regression (OLS), generalized additive models (GAM), least absolute shrinkage and selection operator (LASSO), random forest (RF), support vector machine (SVM), and Gaussian process regression (GPR). We modeled timber volume (m3·ha–1) for four boreal sites using ABA with 2–39 predictors and 20–500 training plots. OLS, GAM, LASSO, and SVM overfitted as the number of predictors approached the number of training plots. They required ≥15 plots per predictor to provide accurate predictions (RMSE ≤30%). GAM required ≥250 plots regardless of the number of predictors. The number of predictors only mildly affected RF and GPR, but they required ≥200 and ≥250 training plots, respectively. RF did not overfit in any circumstances, whereas GPR overfit even with 500 training plots. Overall, using up to 39 predictors did not generally result in overfit, and for most model types, it resulted in better accuracy for sufficiently large datasets (≥250 plots). Numéro de notice : A2022-948 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1139/cjfr-2021-0192 En ligne : https://doi.org/10.1139/cjfr-2021-0192 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100413 [article]

A comparison of linear-mode and single-photon airborne LiDAR in species-specific forest inventories / Janne Raty in IEEE Transactions on geoscience and remote sensing, vol 60 n° 1 (January 2022)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 60 n° 1 (January 2022) . - n° 4401514 Titre : A comparison of linear-mode and single-photon airborne LiDAR in species-specific forest inventories Type de document : Article/Communication Auteurs : Janne Raty, Auteur ; Petri Varvia, Auteur ; Lauri Korhonen, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 4401514 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] altitude [Termes IGN] analyse comparative [Termes IGN] capteur linéaire [Termes IGN] carte de la végétation [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Finlande [Termes IGN] forêt boréale [Termes IGN] instrumentation Leica [Termes IGN] instrumentation Riegl [Termes IGN] inventaire forestier étranger (données) [Termes IGN] photon [Termes IGN] Pinophyta [Termes IGN] semis de points [Termes IGN] signal laser Résumé : (auteur) Single-photon airborne light detection and ranging (LiDAR) systems provide high-density data from high flight altitudes. We compared single-photon and linear-mode airborne LiDAR for the prediction of species-specific volumes in boreal coniferous-dominated forests. The LiDAR data sets were acquired at different flight altitudes using Leica SPL100 (single-photon, 17 points ⋅ m−2 ), Riegl VQ-1560i (linear-mode, 11 points ⋅ m−2 ), and Leica ALS60 (linear-mode, 0.6 points ⋅ m−2 ) LiDAR systems. Volumes were predicted at the plot-level using Gaussian process regression with predictor variables extracted from the LiDAR data sets and aerial images. Our findings showed that the Leica SPL100 produced a greater mean root-mean-squared error (RMSE) value (41.7 m3 ⋅ ha −1 ) than the Leica ALS60 (39.3 m3 ⋅ ha −1 ) in the prediction of species-specific volumes. Correspondingly, the Riegl VQ-1560i (mean RMSE = 33.0 m3 ⋅ ha −1 ) outperformed both the Leica ALS60 and the Leica SPL100. We found that the cumulative distributions of the first echo heights >1.3 m were rather similar among the data sets, whereas the last echo distributions showed larger differences. We conclude that the Leica SPL100 data set is suitable for area-based LiDAR inventory by tree species although the prediction errors are greater than with data obtained using the modern linear-mode LiDAR, such as Riegl VQ-1560i. Numéro de notice : A2022-026 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1109/TGRS.2021.3060670 Date de publication en ligne : 04/03/2021 En ligne : https://doi.org/10.1109/TGRS.2021.3060670 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99257 [article]

Comparing nearest neighbor configurations in the prediction of species-specific diameter distributions / Janne Raty in Annals of Forest Science, vol 75 n° 1 (March 2018)  

Public [article]  inAnnals of Forest Science > vol 75 n° 1 (March 2018) Titre : Comparing nearest neighbor configurations in the prediction of species-specific diameter distributions Type de document : Article/Communication Auteurs : Janne Raty, Auteur ; Petteri Packalen, Auteur ; Matti Maltamo, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] classificateur non paramétrique [Termes IGN] diamètre des arbres [Termes IGN] Finlande [Termes IGN] forêt boréale [Termes IGN] image aérienne [Termes IGN] télémètre laser aéroporté [Termes IGN] volume en bois [Vedettes matières IGN] Sylviculture Résumé : (Auteur) We examine how the configurations in nearest neighbor imputation affect the performance of predicted species-specific diameter distributions. The simultaneous nearest neighbor imputation for all tree species and separate imputation by tree species are evaluated with total volume calibration as a prediction method for diameter distributions. This study considers the predictions of species-specific diameter distributions in Finnish boreal forests by means of airborne laser scanning (ALS) data and aerial images. The aim was to investigate different configurations in non-parametric nearest neighbor (NN) imputation and to determine how changes in configurations affect prediction error rates for timber assortment volumes and the error indices of the diameter distributions. Non-parametric NN imputation was used as a modeling method and was applied in two different ways: (1) diameter distributions were predicted at the same time for all tree species by simultaneous NN imputation, and (2) diameter distributions were predicted for one tree species at a time by separate NN imputation. Calibration to a regression-based total volume prediction was applied in both cases. The results indicated that significant changes in the volume prediction error rates for timber assortment and for error indices can be achieved by the selection of responses, calibration to total volume, and separate NN imputation by tree species. verall, the selection of response variables in NN imputation and calibration to total volume improved the predicted diameter distribution error rates. The most successful prediction performance of diameter distribution was achieved by separate NN imputation by tree species. Numéro de notice : A2018-314 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-018-0711-0 Date de publication en ligne : 06/03/2018 En ligne : https://doi.org/10.1007/s13595-018-0711-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90438 [article]

Quality testing of system cameras / Janne Raty (1988)

Public Titre : Quality testing of system cameras Type de document : Rapport Auteurs : Janne Raty, Auteur ; J. Hakkarainen, Auteur Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 1988 Collection : Reports of the Finnish Geodetic Institute num. 88-5 Importance : 18 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-711-124-9 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes IGN] calibrage [Termes IGN] chambre de prise de vues argentique [Termes IGN] lentille [Termes IGN] mesurage d'angles [Termes IGN] microdensitométrie [Termes IGN] objectif photographique [Termes IGN] qualité instrumentale [Termes IGN] spécification de produit Index. décimale : 30.03 Instruments de géodésie Numéro de notice : 57772 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=43957

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
57772-01	30.03	Livre	Centre de documentation	En réserve M-103	Disponible