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Graph-based synchronous collaborative mapping / Xiaochen Kang in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 28 - 47 Titre : Graph-based synchronous collaborative mapping Type de document : Article/Communication Auteurs : Xiaochen Kang, Auteur Année de publication : 2015 Article en page(s) : pp 28 - 47 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie [Termes descripteurs IGN] automatisation des processus [Termes descripteurs IGN] cartographie collaborative [Termes descripteurs IGN] corrélation à l'aide de traits caractéristiques [Termes descripteurs IGN] corrélation automatique de points homologues [Termes descripteurs IGN] synchronisation Résumé : (auteur) Collaborative mapping is different from other collaborative editing systems because of spatial characterization and spatial dependence. Spatial operations on a mapping feature influence that feature and also the neighbouring features. Therefore, conflicts are likely to occur if common features or interrelated features are processed concurrently. For collaborative editing systems, the widely used multiversioning technique enables improved concurrency, which, however, is at the cost of synchronous data consistency. To maintain the synchronous consistency in collaborative mapping, a practical framework called the spatial operation dependence graph is proposed. The features are expressed as graph vertexes, while the dependences among the operations on features are expressed as graph edges. Through maintaining locking statuses of the vertexes, interdependent operations on features are arbitrated according to the temporal order, while independent operations can concurrently proceed. The utility of this framework is demonstrated through a prototype system, Co-Mapping. Numéro de notice : A2015-244 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76242 [article]

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Mediterranean forest species mapping using classification of Hyperion imagery / Georgia Galidaki in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 48 - 61 Titre : Mediterranean forest species mapping using classification of Hyperion imagery Type de document : Article/Communication Auteurs : Georgia Galidaki, Auteur ; Ioannis Gitas, Auteur Année de publication : 2015 Article en page(s) : pp 48 - 61 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] approche pixel [Termes descripteurs IGN] carte de la végétation [Termes descripteurs IGN] classification barycentrique [Termes descripteurs IGN] classification orientée objet [Termes descripteurs IGN] forêt méditerranéenne [Termes descripteurs IGN] image EO1-Hyperion [Termes descripteurs IGN] image hyperspectrale Résumé : (auteur) Regional operational forest species mapping is an active research topic that aims to provide the systematic and updatable information necessary for understanding and monitoring the rapidly changing forest environment. In this study, we investigated the potential of satellite hyperspectral imagery in regional forest species mapping by employing a pixel-based and an object-based nearest neighbour classifier in two different Mediterranean study areas. The overall thematic accuracy of the produced maps was assessed using reference data collected in the field and ranged between 0.72 and 0.83. No approach was found to be superior for the study areas. The McNemar test showed no statistically significant difference at the 95% confidence level in the classification accuracies achieved by the two approaches. Both pixel- and object-based approaches provide useful maps, suggesting that regional forest species mapping from space has much potential. Numéro de notice : A2015-245 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76243 [article]

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Prediction of the presence of topsoil nitrogen from spaceborne hyperspectral data / Binny Gopal in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 82 - 92 Titre : Prediction of the presence of topsoil nitrogen from spaceborne hyperspectral data Type de document : Article/Communication Auteurs : Binny Gopal, Auteur ; Amba Shetty, Auteur ; B. J. Ramya, Auteur Année de publication : 2015 Article en page(s) : pp 82 - 92 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] azote [Termes descripteurs IGN] détection [Termes descripteurs IGN] état de surface du sol [Termes descripteurs IGN] image EO1-Hyperion [Termes descripteurs IGN] image hyperspectrale [Termes descripteurs IGN] Inde [Termes descripteurs IGN] régression non linéaire [Termes descripteurs IGN] système d'information géographique [Termes descripteurs IGN] terre arable Résumé : (auteur) Conventional methods of soil nitrogen extraction are time consuming, expensive and tedious. Remote sensing and Geographical Information System technologies can be used for the rapid and efficient prediction of the presence of soil nitrogen. However, studies are limited by and large to fields of larger and homogeneous units. This research concentrates on the prediction of topsoil nitrogen from harvested, scattered and small-sized agricultural fields of India using hyperspectral data. Spaceborne hyperspectral Hyperion data are used for the prediction of the presence of nitrogen. Multivariate partial least square regression method was used to predict the presence of nitrogen from reflectance. Reflectance data were pretreated using moving average and Savitzky–Golay filters which resulted in moderate prediction of R2 0.65 and 0.63 for calibration and validation, respectively. It can be inferred that Hyperion data can be effectively used for the prediction of the presence of soil nitrogen with a moderate level of accuracy even in case of scattered fields and fields of sizes approximately equal to the spatial resolution of the satellite. Numéro de notice : A2015-246 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76244 [article]

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An analysis of urban expansion and its associated thermal characteristics using Landsat imagery / Wei Huang in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 93 - 103 Titre : An analysis of urban expansion and its associated thermal characteristics using Landsat imagery Type de document : Article/Communication Auteurs : Wei Huang, Auteur ; Yongnian Zeng, Auteur ; Songnian Li, Auteur Année de publication : 2015 Article en page(s) : pp 93 - 103 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] cartographie numérique [Termes descripteurs IGN] Chine [Termes descripteurs IGN] effet thermique [Termes descripteurs IGN] ilot thermique urbain [Termes descripteurs IGN] image Landsat-ETM+ [Termes descripteurs IGN] image Landsat-TM [Termes descripteurs IGN] surveillance de l'urbanisation [Termes descripteurs IGN] température au sol [Termes descripteurs IGN] température de luminance Résumé : (auteur) There has been an increasing interest in mapping and monitoring urban land use/land cover using remote sensing techniques. However, there still exist quite a number of challenges in deriving urban extent and its expansion density from remote sensing data quantitatively. This study utilized Landsat TM/ETM+ remote sensing data to assess urban expansion and its thermal characteristics with a case study in the city of Changsha, China. We proposed a new approach for quantitatively determining built-up area, its expansion density and their respective relationship with land surface temperature (LST) patterns. An urban expansion metric was also developed using a moving window mechanism to identify urban built-up area and its expansion density based on selected threshold values. The study suggested that urban extent and its expansion density, as well as surface thermal characteristics and patterns could be identified through quantitatively derived remotely sensed indices and LST, which offer meaningful characteristics in quantifying urban expansion density and urban thermal pattern. Results from the case study demonstrated that: (1) the built-up area and urban expansion density have significantly increased in the city of Changsha from 1990 to 2001; and (2) the differences of urban expansion densities correspond to thermal effects, where a high percentage of imperviousness is usually associated with the area covered by high surface temperature. Numéro de notice : A2015-247 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/IMAGERIE/URBANISME Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76245 [article]

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Topographic correction of ALOS-PALSAR images using InSAR-derived DEM / Anup Das in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 145 - 153 Titre : Topographic correction of ALOS-PALSAR images using InSAR-derived DEM Type de document : Article/Communication Auteurs : Anup Das, Auteur ; Ritesh Agrawal, Auteur ; Shiv Mohan, Auteur Année de publication : 2015 Article en page(s) : pp 145 - 153 Note générale : Bibliogaphie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes descripteurs IGN] correction géométrique [Termes descripteurs IGN] image ALOS-PALSAR [Termes descripteurs IGN] interféromètrie par radar à antenne synthétique [Termes descripteurs IGN] MNS SRTM [Termes descripteurs IGN] modèle numérique de surface [Termes descripteurs IGN] photogrammétrie numérique [Termes descripteurs IGN] Rajasthan (Inde ; état) Résumé : (Auteur) Topographic corrections of synthetic aperture radar (SAR) images over hilly regions are vital for retrieval of correct backscatter values associated with natural targets. The coarse resolution external digital elevation models (DEM) available for topographic corrections of high resolution SAR images often result into degradation of spatial resolution or improper estimation of backscatter values in SAR images. Also, many a times the external DEMs do not spatially co-register well with the SAR data. The present study showcases the methodology and results of topographic correction of ALOS-PALSAR image using high resolution DEM generated from the same data. High resolution DEMs of Jaipur region, India were generated using multiple pair SAR images acquired from ALOS-PALSAR using interferometric (InSAR) techniques. The DEMs were validated using differential global positioning system measured elevation values as ground control points and were compared with photogrammetric DEM (advanced spaceborne thermal emission and reflection radiometer – ASTER) and SRTM (Shuttle Radar Topography Mission) DEM. It was observed that ALOS-PALSAR images with optimum baseline parameters produced high resolution DEM with better height accuracy. Finally, the validated DEM was used for topographic correction of ALOS-PALSAR images of the same region and were found to produce better result as compared with ASTER and SRTM-DEM. Numéro de notice : A2015-300 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76500 [article]

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A comparison between analytical aerial photogrammetry, laser scanning, total station and global positioning system surveys for generation of digital terrain model / Khalid L.A. El-Ashmawy in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 154 - 162 Titre : A comparison between analytical aerial photogrammetry, laser scanning, total station and global positioning system surveys for generation of digital terrain model Type de document : Article/Communication Auteurs : Khalid L.A. El-Ashmawy, Auteur Année de publication : 2015 Article en page(s) : pp 154 - 162 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] lever tachéométrique [Termes descripteurs IGN] modèle numérique de terrain [Termes descripteurs IGN] photogrammétrie aérienne [Termes descripteurs IGN] positionnement par GPS [Termes descripteurs IGN] tachéomètre électronique [Termes descripteurs IGN] télémétrie laser terrestre Résumé : (Auteur) The present paper compares between four data sources for creating digital terrain models (DTMs), based on analytical aerial photogrammetry, laser scanning, total station (TS) and global positioning system surveys. The case study presents the comparative results obtained using the methods listed above. After obtaining the ground coordinates of points using each method, DTMs were created using Surfer Software to establish comparison consistency. To check accuracy of each method used, a series of 100 independent points were collected at random positions over the case study area using the TS for horizontal position and a digital level for elevation. The comparison of the results of the methods was performed based on accuracy and efficiency aspects. The results have shown that TS and terrestrial laser scanners (TLSs) could represent precise, effective and rapid solutions to produce economical and accurate DTMs. Also, using TLSs allow more various possibilities of data representation. Numéro de notice : A2015-301 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76502 [article]

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Land cover dynamics monitoring with Landsat data in Kunming, China: a cost-effective sampling and modelling scheme using Google Earth imagery and random forests / Ning Lu in Geocarto international, vol 30 n° 1 - 2 (January - February 2015)

Public [article]  inGeocarto international > vol 30 n° 1 - 2 (January - February 2015) . - pp 186 - 201 Titre : Land cover dynamics monitoring with Landsat data in Kunming, China: a cost-effective sampling and modelling scheme using Google Earth imagery and random forests Type de document : Article/Communication Auteurs : Ning Lu, Auteur Année de publication : 2015 Article en page(s) : pp 186 - 201 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] classification par forêts aléatoires [Termes descripteurs IGN] coût [Termes descripteurs IGN] détection de changement [Termes descripteurs IGN] échantillonnage [Termes descripteurs IGN] forêt [Termes descripteurs IGN] Google Earth [Termes descripteurs IGN] image Aqua-MODIS [Termes descripteurs IGN] image Terra-MODIS [Termes descripteurs IGN] modélisation environnementale [Termes descripteurs IGN] occupation du sol [Termes descripteurs IGN] surveillance forestière [Termes descripteurs IGN] Yunnan (Chine) Résumé : (Auteur) Changes in forest composition impact ecological services, and are considered important factors driving global climate change. A hybrid sampling method along with a modelling approach to map current and past land cover in Kunming, China is reported. MODIS land cover (2001–2011) data-sets were used to detect pixels with no apparent change. Around 3000 ‘no change points’ were systematically selected and sampled using Google Earth’s high-resolution imagery. Thirty-five per cent of these points were verified and used for training and validation. We used Random forests to classify multi-temporal Landsat imagery. Results show that forest cover has had a net decrease of 14385 ha (1.3% of forest area), which was primary converted to shrublands (11%), urban and barren land (2.7%) and agriculture (2.5%). Our validation indicates an overall accuracy (Kappa) of 82%. Our methodology can be used to consistently map the dynamics of land cover change in similar areas with minimum costs. Numéro de notice : A2015-302 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76503 [article]

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