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Evaluating NDVI-based emissivities of MODIS bands 31 and 32 using emissivities derived by day/night LST algorithm / M. Momeni in Remote sensing of environment, vol 106 n° 2 (30/01/2007)
[article]
Titre : Evaluating NDVI-based emissivities of MODIS bands 31 and 32 using emissivities derived by day/night LST algorithm Type de document : Article/Communication Auteurs : M. Momeni, Auteur ; M.R. Saradjan, Auteur Année de publication : 2007 Article en page(s) : pp 190 - 198 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande spectrale
[Termes IGN] écart type
[Termes IGN] emissivité
[Termes IGN] erreur systématique
[Termes IGN] image Terra-MODIS
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] occupation du sol
[Termes IGN] régression linéaire
[Termes IGN] seuillage d'image
[Termes IGN] température au sol
[Termes IGN] température de surface
[Termes IGN] variation diurne
[Termes IGN] zone arideRésumé : (Auteur) Surface emissivity estimation is a significant factor for the land surface temperature estimation from remotely sensed data. For fully vegetated surfaces, the emissivity estimation is performed in a simple manner since the emissivity is relatively uniform. However, for arid land with sparse vegetation, the estimation is more complicated since the emissivity of the exposed soil and rock is highly variable. In this study, mean and difference emissivity for bands 31 and 32 of MODIS sensor have been derived based on NDVI values. First, the NDVI thresholds have been determined to separate bare soil, partially vegetated soil and fully vegetated land. Then regression relations have been derived to estimate mean and difference emissivity of the bare soil samples and partially vegetated surfaces. A constant emissivity is also used for fully vegetated area. Along with the correlations, standard deviations of the regression relations have been examined for a set of representative soil types. Standard deviations smaller than 0.003 in mean emissivity and smaller than 0.004 in difference emissivity are resulted in regression linear relations. Evaluation of the NDVI derived regression relations has been performed using the results of MODIS Day/Night Land Surface Temperature (LST) algorithm on a pair of MODIS images. Using around 45,500 pixels with different soil and land cover types, emissivity of each pixel in bands 31 and 32 have been estimated. The calculated emissivities have been compared with emissivities calculated by MODIS Day/Night LST algorithm. Biases and standard deviations of NDVI-based relations show relatively high agreement for mean and difference emissivity relations with Day/Night method results. It may be concluded that the proposed algorithm can be used as a rather simple alternative to complex emissivity estimation algorithms. Copyright Elsevier Numéro de notice : A2007-021 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2006.08.005 En ligne : https://doi.org/10.1016/j.rse.2006.08.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28387
in Remote sensing of environment > vol 106 n° 2 (30/01/2007) . - pp 190 - 198[article]Wind resource assessment from C-band SAR / M.B. Christiansen in Remote sensing of environment, vol 105 n° 1 (15/11/2006)
[article]
Titre : Wind resource assessment from C-band SAR Type de document : Article/Communication Auteurs : M.B. Christiansen, Auteur ; W Koch, Auteur Année de publication : 2006 Article en page(s) : pp 68 - 81 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse comparative
[Termes IGN] bande C
[Termes IGN] direction
[Termes IGN] écart type
[Termes IGN] erreur systématique
[Termes IGN] gradient
[Termes IGN] image Envisat-ASAR
[Termes IGN] image ERS-SAR
[Termes IGN] Nord, mer du
[Termes IGN] vent
[Termes IGN] vitesseRésumé : (Auteur) Using accurate inputs of wind speed is crucial in wind resource assessment, as predicted power is proportional to the wind speed cubed. First, wind speeds retrieved from a series of 91 ERS-2 SAR and Envisat ASAR images, at moderate wind speeds (2–15 m s- 1), were validated against in situ measurements from an offshore mast in the North Sea. The wind direction input, necessary for SAR wind speed retrievals, was obtained from the meteorological mast and from a local gradient analysis of wind streaks in the SAR images. A wind speed standard deviation of not, vert, similar 1.1 m s- 1 was found when in situ wind directions were used. The use of local gradient wind directions yielded a standard deviation of not, vert, similar 1.3 m s- 1. Wind speeds retrieved from three geophysical model functions (CMOD-IFR2, CMOD4, and CMOD5) were compared. The best approximation to the in situ measurements of wind speed was found for CMOD-IFR2, despite a bias on the order of - 0.3 m s- 1. CMOD4 retrievals also underestimated the wind speed, whereas the bias on CMOD5 retrievals was negligible. Then, wind resource assessments were made from the SAR-based wind observations to show how errors in wind speed from the different SAR wind retrievals were reflected in the wind statistics. The mean wind speed, obtained for all of the 91 SAR scenes, was linked closely to the bias of SAR wind retrievals. Agreement to 1 15% of the in situ measurements was found for all the wind retrieval methods tested. The accuracy of power density estimates for the entire data set was evaluated by the standard deviation of SAR wind retrievals relative to the in situ measurements. SAR wind fields retrieved with CMOD-IFR2, using in situ wind direction inputs, exactly yielded the power density predicted from in situ measurements alone. The SAR-based wind resource assessment also corresponded well to predictions from longer time series of in situ measurements. This indicates that a reliable wind resource assessment may be achieved from a series of randomly selected SAR images. The findings presented here could be useful in future wind resource assessment based on SAR images. Copyright Elsevier Numéro de notice : A2006-503 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2006.06.005 En ligne : https://doi.org/10.1016/j.rse.2006.06.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28227
in Remote sensing of environment > vol 105 n° 1 (15/11/2006) . - pp 68 - 81[article]Extraction of ground control points (GCPs) from synthetic aperture radar images and SRTM DEM / S.H. Hong in International Journal of Remote Sensing IJRS, vol 27 n°18 - 19 - 20 (October 2006)
[article]
Titre : Extraction of ground control points (GCPs) from synthetic aperture radar images and SRTM DEM Type de document : Article/Communication Auteurs : S.H. Hong, Auteur ; Hyung-Sup Jung, Auteur ; J.S. Won, Auteur Année de publication : 2006 Article en page(s) : pp 3813 - 3829 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] écart type
[Termes IGN] extraction
[Termes IGN] image ERS-SAR
[Termes IGN] image IRS
[Termes IGN] MNS SRTM
[Termes IGN] modèle numérique de surface
[Termes IGN] point d'appui
[Termes IGN] radargrammétrieRésumé : (Auteur) Qualified ground control points (GCPs) are crucial in the geolocation of a remotely sensed image. If a region has no published map, the geographical coordinates of GCPs must be obtained indirectly. Although these can be re-constructed from a synthetic aperture radar (SAR) image using sensor position and velocity, this conventional method does not provide accurate GCPs owing to the variable elevations of actual topography. We propose an inverse geolocation method for GCPs by SAR simulation. This improves the accuracy of extracted GCPs by accommodating topographic effects, and requires a high-resolution digital elevation model (DEM) and SAR with precise orbit data. The errors in the northing derive mainly from the imaging pulse time, and were improved by applying an azimuth time correction. In this study ERS SAR data with precise Delft orbit and shuttle radar topography mission (SRTM) DEM were used. Mean values for the planimetric distance error in the GCPs were 4.1 and 5.4 m with standard deviations of 10.6 and 16.9 m in northing and easting, respectively. The obtained GCPs were applied to an IRS image for geo-rectification, and the result was mean image positional errors of 3.6 and 2.7 m with standard deviations of 8.4 and 15.4 m in northing and easting, respectively. The root mean square errors are 9.0 and 15.3 m in northing and easting, respectively. Copyright Taylor & Francis Numéro de notice : A2006-457 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160600658115 En ligne : https://doi.org/10.1080/01431160600658115 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28181
in International Journal of Remote Sensing IJRS > vol 27 n°18 - 19 - 20 (October 2006) . - pp 3813 - 3829[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 080-06101 RAB Revue Centre de documentation En réserve L003 Disponible Multi-technique comparison of tropospheric zenith delays derived during the CONT02 campaign / Pascal Willis in Journal of geodesy, vol 79 n° 10-11 (February 2006)
[article]
Titre : Multi-technique comparison of tropospheric zenith delays derived during the CONT02 campaign Type de document : Article/Communication Auteurs : Pascal Willis , Auteur ; K. Snajdrova, Auteur ; Johannes Böhm , Auteur ; Rüdiger Haas, Auteur Année de publication : 2006 Article en page(s) : pp 613 - 623 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] distance zénithale
[Termes IGN] données WVR
[Termes IGN] écart type
[Termes IGN] erreur systématique
[Termes IGN] météorologie
[Termes IGN] positionnement par DORIS
[Termes IGN] positionnement par GPS
[Termes IGN] prévision météorologique
[Termes IGN] propagation troposphérique
[Termes IGN] traitement du signal
[Termes IGN] troposphèreRésumé : (Auteur) In October 2002, 15 continuous days of Very Long Baseline Interferometry (VLBI) data were observed in the Continuous VLBI 2002 (CONT02) campaign. All eight radio telescopes involved in CONT02 were co-located with at least one other space-geodetic technique, and three of them also with a Water Vapor Radiometer (WVR). The goal of this paper is to compare the tropospheric zenith delays observed during CONT02 by VLBI, Global Positioning System (GPS), Doppler Orbitography Radiopositioning Integrated by Satellite (DORIS) and WVR and te, compare them also with operational pressure level data from the European Centre for Medium-Range Weather Forecasts (ECMWF). We show that the tropospheric zenith delays from VLBI and GPS are in good agreement at the 3-7 mm level. However, while only small biases can be found for most of the stations, at Kokee Park (Hawaii, USA) and Westford (Massachusetts, USA) the zenith delays derived by GPS are larger by more than 5 mm than those from VLBI. At three of the four DORIS stations, there is also a fairly good agreement with GPS and VLBI (about 10 mm), but at Kokee Park the agreement is only at about 30 mm standard deviation, probably due to the much older installation and type of DORIS equipment. This comparison also allows testing of different DORIS analysis strategies with respect to their real impact on the precision of the derived tropospheric parameters. Ground truth information about the zenith delays can also be obtained from the ECMWF numerical weather model and at three sites using WVR measurements, allowing for comparisons with results from the space-geodetic techniques. While there is a good agreement (with some problems mentioned above about DORIS) among the space-geodetic techniques, the comparison with WVR and ECMWF is at a lower accuracy level. The complete CONT02 data set is sufficient to derive a good estimate of the actual precision and accuracy of each geodetic technique for applications in meteorology. Numéro de notice : A2006-088 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-005-0010-z En ligne : https://doi.org/10.1007/s00190-005-0010-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27815
in Journal of geodesy > vol 79 n° 10-11 (February 2006) . - pp 613 - 623[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-06011 RAB Revue Centre de documentation En réserve L003 Disponible 266-06012 RAB Revue Centre de documentation Revues en salle Disponible The accuracy of grid digital elevation models linearly constructed from scattered sample data / F. Aguilar in International journal of geographical information science IJGIS, vol 20 n° 2 (february 2006)
[article]
Titre : The accuracy of grid digital elevation models linearly constructed from scattered sample data Type de document : Article/Communication Auteurs : F. Aguilar, Auteur ; M. Aguilar, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 169 - 192 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] couple stéréoscopique
[Termes IGN] écart type
[Termes IGN] échantillonnage de données
[Termes IGN] erreur d'échantillon
[Termes IGN] erreur moyenne quadratique
[Termes IGN] image aérienne
[Termes IGN] interpolation linéaire
[Termes IGN] maille carrée
[Termes IGN] modèle numérique de surface
[Termes IGN] modélisation 3D
[Termes IGN] pente
[Termes IGN] propagation d'erreur
[Termes IGN] rugosité du sol
[Termes IGN] système d'information géographiqueRésumé : (Auteur) In this paper, a theoretical-empirical model is developed for modelling the accuracy of a grid digital elevation model (DEM) linearly constructed from scattered sample data. The theoretical component integrates sample data accuracy in the model by means of the error-propagation theory. The empirical component seeks to model what is known as information loss, i.e. the sum of the error due purely to sampling the continuous terrain surface with a finite grid interval and the interpolation error. For this purpose, randomly spaced data points, supposed to be free of error, were converted into regularly gridded data points using triangulation with linear interpolation. Original sample data were collected with a 2 x 2 m sampling interval from eight different morphologies, from flat terrain to highly rugged terrain, applying digital photogrammetric methods to large-scale aerial stereo imagery (1 :5000). The DEM root mean square error was calculated by the true validation method over several sets of check points, obtaining the different sampling densities tested in this work. Several empirical models are calibrated and validated with the experimental data set by modelling the DEM accuracy by combining two variables such as sampling density and a descriptive attribute of terrain morphology. These empirical models presented a morphology based on the product of two potential functions, one related to the terrain roughness and another related to the sampling density. The terrain descriptors tested were average terrain slope, standard deviation of terrain slope, standard deviation of unitary vectors perpendicular to the topographic surface (SDUV), standard deviation of the difference in height between adjacent samples in the grid DEM (SDHD), and roughness estimation by first-, second-, or third-degree surface fitting error. The values obtained for those terrain descriptors were reasonably independent from the number and spatial distribution of the sample data. The models based on descriptors SDHD, SDUV, and standard deviation of slope provided a good fitting to the data observed (R 2> 0.94) in the calibration phase, model SDHD being the one that yielded the best results in validation. Therefore, it would be possible to establish a priori the optimum grid size required to generate or store a DEM of a particular accuracy, with the saving in computing time and file size that this would mean for the digital flow of the mapping information in GIS. Numéro de notice : A2006-066 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/13658810500399670 En ligne : https://doi.org/10.1080/13658810500399670 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27793
in International journal of geographical information science IJGIS > vol 20 n° 2 (february 2006) . - pp 169 - 192[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-06021 RAB Revue Centre de documentation En réserve L003 Disponible 079-06022 RAB Revue Centre de documentation En réserve L003 Disponible Uncertainty analysis for soil-terrain models / T.F.A. Bishop in International journal of geographical information science IJGIS, vol 20 n° 2 (february 2006)PermalinkEvaluation de la précision globale d'un positionnement GPS en réseau / F. Molle (2005)PermalinkL'arrêté qui précise les tolérances des levés / Michel Kasser in Géomètre, vol 2003 n° 12 (décembre 2003)PermalinkFuzzy logic system for road identification using Ikonos images / J. Amini in Photogrammetric record, vol 17 n° 99 (April - September 2002)PermalinkAnalyse statistique des données expérimentales / K. Protassov (2002)PermalinkErrors and accuracy estimates of laser data acquired by various laser scanning systems for topographic applications / E.J. Huising in ISPRS Journal of photogrammetry and remote sensing, vol 53 n° 5 (September - October 1998)PermalinkEstimation sans biais des variances des différents groupes d'observations dans une compensation hétérogène / Namik Kopliku (1990)PermalinkSpatial correlation in reflected radiation from the ground and its implications for sampling and mapping by ground-based radiometry / R. Webster in Remote sensing of environment, vol 29 n° 1 (July 1989)PermalinkHeights above the geoid for mapping control by Doppler translocation / M.C. Breach in Survey review, vol 29 n° 230 (October 1988)PermalinkPremiers résultats SPOT en Lorraine relatifs aux prairies permanentes / Monique Benoit in Bulletin [Société Française de Photogrammétrie et Télédétection], n° 106 (Avril 1987)Permalink