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Using hachures to construct a 3D doline model automatically / Nai Yang in Cartographica, vol 50 n° 2 (Summer 2015)  

Public [article]  inCartographica > vol 50 n° 2 (Summer 2015) . - pp 86 - 93 Titre : Using hachures to construct a 3D doline model automatically Type de document : Article/Communication Auteurs : Nai Yang, Auteur ; Lin Wan, Auteur ; G. Zheng, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 86 - 93 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rédaction cartographique [Termes IGN] effondrement de terrain [Termes IGN] grotte [Termes IGN] hachure [Termes IGN] représentation cartographique 3D Résumé : (auteur) All types of relief features are usually represented by a unified digital terrain model on 3D topographic maps. Few studies have considered the differences in relief characteristics and terrain complexity. Hachures are often used to construct the relief symbols on 2D topographic maps, but they are less used on 3D topographic maps. This article uses hachures to construct a 3D doline model and divides them into three types: outlines, ridge lines, and break lines. We present the extraction method for doline outlines, consider the rules of visual perception under different illumination conditions, and study the mathematical models for representing the morphological characteristics of the doline with regard to the following aspects: width, arrangement density, and grey value of hachures. Finally, we introduce a process for 3D modelling of dolines on the basis of the above discussion. Experimental results indicate that the proposed model achieves a good 3D visual representation of dolines. Furthermore, the proposed model can also be used as a reference for the creation of 3D models of other negative relief features. Numéro de notice : A2015-273 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.3138/cart.50.2.2793 En ligne : http://www.utpjournals.press/doi/full/10.3138/cart.50.2.2793 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76386 [article]

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031-2015021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Retrieval of effective leaf area index in heterogeneous forests with terrestrial laser scanning / G. Zheng in IEEE Transactions on geoscience and remote sensing, vol 51 n° 2 (February 2013)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 51 n° 2 (February 2013) . - pp 777 - 787 Titre : Retrieval of effective leaf area index in heterogeneous forests with terrestrial laser scanning Type de document : Article/Communication Auteurs : G. Zheng, Auteur ; L. Moskal, Auteur ; S.H. Kim, Auteur Année de publication : 2013 Article en page(s) : pp 777 - 787 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] forêt [Termes IGN] image hémisphérique [Termes IGN] Leaf Area Index [Termes IGN] projection azimutale équivalente de lambert [Termes IGN] projection stéréographique [Termes IGN] rastérisation [Termes IGN] semis de points [Termes IGN] télémétrie laser aéroporté [Termes IGN] télémétrie laser terrestre Résumé : (Auteur) Terrestrial laser scanner (TLS)-based leaf area index (LAI) retrieval is an appealing concept, due to the ability to capture structural information of canopies as 3D point cloud data (PCD). TLS-based LAI estimation methods promise a nondestructive tool for spatially explicit calibration of LAI estimated by aerial or satellite remote sensing techniques. These methods also overcome the sky condition restrictions of on-ground optical instruments such as hemispherical photography frequently used for LAI estimation. This paper presents a new method for estimating the effective LAI (LAIe) directly from PCD generated by TLS in heterogeneous forests. We converted the 3-D PCD into 2-D raster images, similar to hemispherical photographs, using two geometrical projection techniques in order to estimate gap fraction and LAIe using a linear least squares method. Our results indicated that the TLS-based algorithm was able to capture the variability in LAIe of forest stands with a range of densities. The TLS-based LAIe estimation method explained 89.1% (rmse = 0.01 ; p Numéro de notice : A2013-080 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2205003 En ligne : https://doi.org/10.1109/TGRS.2012.2205003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32218 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-2013021	RAB	Revue	Centre de documentation	En réserve L003	Disponible