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Mapping impervious surfaces with a hierarchical spectral mixture analysis incorporating endmember spatial distribution / Zhenfeng Shao in Geo-spatial Information Science, vol 25 n° 4 (December 2022)  

Public [article]  inGeo-spatial Information Science > vol 25 n° 4 (December 2022) . - pp 550 - 567 Titre : Mapping impervious surfaces with a hierarchical spectral mixture analysis incorporating endmember spatial distribution Type de document : Article/Communication Auteurs : Zhenfeng Shao, Auteur ; Yuan Zhang, Auteur ; Cheng Zhang, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 550 - 567 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse de mélange spectral d’extrémités multiples [Termes IGN] approche hiérarchique [Termes IGN] Chine [Termes IGN] distribution spatiale [Termes IGN] image Gaofen [Termes IGN] image Landsat-OLI [Termes IGN] scène urbaine [Termes IGN] surface imperméable Résumé : (auteur) Impervious surface mapping is essential for urban environmental studies. Spectral Mixture Analysis (SMA) and its extensions are widely employed in impervious surface estimation from medium-resolution images. For SMA, inappropriate endmember combinations and inadequate endmember classes have been recognized as the primary reasons for estimation errors. Meanwhile, the spectral-only SMA, without considering urban spatial distribution, fails to consider spectral variability in an adequate manner. The lack of endmember class diversity and their spatial variations lead to over/underestimation. To mitigate these issues, this study integrates a hierarchical strategy and spatially varied endmember spectra to map impervious surface abundance, taking Wuhan and Wuzhou as two study areas. Specifically, the piecewise convex multiple-model endmember detection algorithm is applied to automatically hierarchize images into three regions, and distinct endmember combinations are independently developed in each region. Then, spatially varied endmember spectra are synthesized through neighboring spectra using the distance-based weight. Comparative analysis indicates that the proposed method achieves better performance than Hierarchical SMA and Fixed Four-endmembers SMA in terms of MAE, SE, and RMSE. Further analysis suggests that the hierarchical strategy can expand endmember class types and considerably improve the performance for the study areas in general, specifically in less developed areas. Moreover, we find that spatially varied endmember spectra facilitate the reduction of heterogeneous surface material variations and achieve the improved performance in developed areas. Numéro de notice : A2022-890 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/10095020.2022.2028535 Date de publication en ligne : 02/03/2022 En ligne : https://doi.org/10.1080/10095020.2022.2028535 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102237 [article]

Mapping spatial distribution of forest age in China / Yuan Zhang in Earth and space science, vol 4 n° 3 (March 2017)  

Public [article]  inEarth and space science > vol 4 n° 3 (March 2017) . - pp 108 - 116 Titre : Mapping spatial distribution of forest age in China Type de document : Article/Communication Auteurs : Yuan Zhang, Auteur ; Yitong Yao, Auteur ; Xuhui Wang, Auteur ; Yongwen Liu, Auteur ; Shilong Piao, Auteur Année de publication : 2017 Article en page(s) : pp 108 - 116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] carte forestière [Termes IGN] Chine [Termes IGN] Cupressaceae [Termes IGN] distribution spatiale [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] forêt ancienne [Termes IGN] hauteur des arbres [Termes IGN] incertitude des données [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] inventaire forestier étranger (données) [Termes IGN] peuplement forestier [Termes IGN] Pinophyta [Termes IGN] Pinus massoniana [Termes IGN] puits de carbone Résumé : (auteur) Forest stand age is a meaningful metric, which reflects the past disturbance legacy, provides guidelines for forest management practices, and is an important factor in qualifying forest carbon cycles and carbon sequestration potential. Reliable large-scale forest stand age information with high spatial resolutions, however, is difficult to obtain. In this study, we developed a top-down method to downscale the provincial statistics of national forest inventory data into 1 km stand age map using climate data and light detection and ranging-derived forest height. We find that the distribution of forest stand age in China is highly heterogeneous across the country, with a mean value of ~42.6 years old. The relatively young stand age for Chinese forests is mostly due to the large proportion of newly planted forests (0–40 years old), which are more prevailing in south China. Older forests (stand age > 60 years old) are more frequently found in east Qinghai-Tibetan Plateau and the central mountain areas of west and northeast China, where human activities are less intensive. Among the 15 forest types, forests dominated by species of , with the exception of Cunninghamia lanceolata stands, have the oldest mean stand age (136 years), whereas Pinus massoniana forests are the youngest (18 years). We further identified uncertainties associated with our forest age map, which are high in west and northeast China. Our work documents the distribution of forest stand age in China at a high resolution which is useful for carbon cycle modeling and the sustainable use of China's forest resources. Numéro de notice : A2107-277 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1002/2016EA000177 En ligne : https://doi.org/10.1002/2016EA000177 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85298 [article]

Monitoring agricultural soil sealing in peri-urban areas using remote sensing / Shiliang Su in Photogrammetric Engineering & Remote Sensing, PERS, vol 80 n° 4 (April 2014)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 80 n° 4 (April 2014) . - pp 367 - 372 Titre : Monitoring agricultural soil sealing in peri-urban areas using remote sensing Type de document : Article/Communication Auteurs : Shiliang Su, Auteur ; Rui Xiao, Auteur ; Yuan Zhang, Auteur Année de publication : 2014 Article en page(s) : pp 367 - 372 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse diachronique [Termes IGN] croissance urbaine [Termes IGN] image aérienne [Termes IGN] impact sur l'environnement [Termes IGN] occupation du sol [Termes IGN] périphérie urbaine [Termes IGN] revêtement [Termes IGN] Shanghai (Chine) [Termes IGN] surface cultivée [Termes IGN] surface imperméable [Termes IGN] surveillance agricole [Termes IGN] urbanisation Résumé : (Auteur) Soil degradation by expansion-driven sealing increases at an unexpected rate globally, but the dynamics of agricultural soil sealing in peri-urban areas remain poorly understood. This study used aerial photographs to monitor patterns of built-up land expansion and subsequent agricultural soil sealing between 1994 and 2006 in peri-urban areas of Shanghai, China. Results indicated that a total of 152,706.5 ha of agricultural soils were sealed. In particular, residential land and industrial land were the major contributors. Buffer analysis demonstrated that agricultural soils with high proximity to roads and urban centers are more vulnerable to be sealed. Percentage of sealed agricultural soils of total agricultural soils had linear relationships with population growth and economic development. These results quantitatively document the impacts of urbanization on agricultural soil sealing. From a management perspective, we argue that the protection of agricultural soils should be integrated with urban planning efforts in China. Numéro de notice : A2014-211 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.80.4.367 En ligne : https://doi.org/10.14358/PERS.80.4.367 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33114 [article]