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Landsat-7 long-term acquisition plan radiometry: evolution over the time / B. Markham in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 10 (October 2006)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 72 n° 10 (October 2006) . - pp 1129 - 1135 Titre : Landsat-7 long-term acquisition plan radiometry: evolution over the time Type de document : Article/Communication Auteurs : B. Markham, Auteur ; S. Goward, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 1129 - 1135 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] bande spectrale [Termes IGN] image Landsat-ETM+ [Termes IGN] mission spatiale [Termes IGN] nébulosité [Termes IGN] saturation de la couleur [Termes IGN] surveillance météorologique Résumé : (Auteur) The Landsat-7 Enhanced Thematic Mapper Plus instrument has two selectable gains for each spectral band. In the acquisition plan, the gains were initially set to maximize the entropy in each scene. One unintended consequence of this strategy was that, at times, dense vegetation saturated band 4 and deserts saturated all bands. A revised strategy, based on a land-cover classification and sun angle thresholds, reduced saturation, but resulted in gain changes occurring within the same scene on multiple overpasses. As the gain changes cause some loss of data and difficulties for some ground processing systems, a procedure was devised to shift the gain changes to the nearest predicted cloudy scenes. The results are still not totally satisfactory as gain changes still impact some scenes and saturation still occurs, particularly in ephemerally snow-covered regions. A primary conclusion of our experience with variable gain on Landsat-7 is that such an approach should not be employed on future global monitoring missions. Copyright ASPRS Numéro de notice : A2006-425 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.72.10.1129 En ligne : https://doi.org/10.14358/PERS.72.10.1129 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28149 [article]

Landsat: yesterday, today, and tomorrow / D.L. Williams in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 10 (October 2006)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 72 n° 10 (October 2006) . - pp 1171 - 1178 Titre : Landsat: yesterday, today, and tomorrow Type de document : Article/Communication Auteurs : D.L. Williams, Auteur ; S. Goward, Auteur ; T. Arvidson, Auteur Année de publication : 2006 Article en page(s) : pp 1171 - 1178 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] environnement [Termes IGN] image à haute résolution [Termes IGN] image Landsat [Termes IGN] Landsat [Termes IGN] satellite d'observation de la Terre [Termes IGN] télédétection spatiale Résumé : (Auteur) Landsat, first placed in orbit in 1972, established the U.S. as the world leader in land remote sensing. The Landsat system has contributed significantly to the understanding of the Earth’s environment, spawned revolutionary uses of spacebased data by the commercial value-added industry, and encouraged a new generation of commercial satellites that provide regional, high-resolution spatial images. This PE&RS Special Issue provides an update to the 1997 25th Landsat anniversary issue, particularly focused on the contribution of Landsat-7 to the 34+ year history of the Landsat mission. In this overview paper, we place the Landsat-7 system in context and show how mission operations have changed over time, increasingly exploiting the global monitoring capabilities of the Landsat observatory. Although considerable progress was made during the Landsat-7 era, there is much yet to learn about the historical record of Landsat global coverage: a truly valuable national treasure. The time to do so is now, as the memories of the early days of this historic program are fading as we speak. Copyright ASPRS Numéro de notice : A2006-426 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.72.10.1171 En ligne : https://doi.org/10.14358/PERS.72.10.1171 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28150 [article]