Descripteur
Documents disponibles dans cette catégorie (1523)
![](./images/expand_all.gif)
![](./images/collapse_all.gif)
Etendre la recherche sur niveau(x) vers le bas
Optimizing image resolution to maximize the accuracy of hard classification / K.R. Mccloy in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 8 (August 2007)
![]()
[article]
Titre : Optimizing image resolution to maximize the accuracy of hard classification Type de document : Article/Communication Auteurs : K.R. Mccloy, Auteur ; P.K. Bocher, Auteur Année de publication : 2007 Article en page(s) : pp 893 - 903 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] limite de résolution géométrique
[Termes IGN] matrice de confusion
[Termes IGN] précision de la classification
[Termes IGN] théorie des erreurs
[Termes IGN] varianceRésumé : (Auteur) There are three strategies by which the accuracy of classification can be improved after the imagery that will be used for the classification has been chosen. These are to improve the definition of the class decision surfaces, to maximize the between class distances, and to reduce the within class variances. This paper reports on work done to investigate the relationship between classification accuracy and within class variances, where generally accepted measures of accuracy derived from the Confusion Matrix are used as the indicators of classification accuracy. This paper shows that the within class variances are a function of image resolution, and it provides a mechanism based on the Average Local Variance (ALV) function to find the resolution that will yield the highest relative within field classification accuracy by minimizing the within class variances. Copyright ASPRS Numéro de notice : A2007-369 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.8.893 En ligne : http://dx.doi.org/10.14358/PERS.73.8.893 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28732
in Photogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 8 (August 2007) . - pp 893 - 903[article]Spatio-temporal urban landscape change analysis using the Markov chain model and a modified genetic algorithm / J. Tang in International Journal of Remote Sensing IJRS, vol 28 n°15-16 (August 2007)
![]()
[article]
Titre : Spatio-temporal urban landscape change analysis using the Markov chain model and a modified genetic algorithm Type de document : Article/Communication Auteurs : J. Tang, Auteur ; L. Wang, Auteur ; Z. Yao, Auteur Année de publication : 2007 Article en page(s) : pp 3255 - 3271 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] algorithme génétique
[Termes IGN] analyse spatio-temporelle
[Termes IGN] chaîne de Markov
[Termes IGN] Chine
[Termes IGN] image Landsat
[Termes IGN] modèle de Markov
[Termes IGN] prévision
[Termes IGN] urbanisationRésumé : (Auteur) The landscape pattern of Daqing City, China, has undergone a significant change over the past 20 years, as a result of the rapid urbanization process. To understand how urbanization has influenced the landscape in Daqing City, the largest base of the petrochemical industry in China, we conducted a series of spatial analyses with landscape pattern maps obtained from Landsat images in 1979, 1990 and 2000. Results indicate that a substantial urban area has been extended during the past two decades, along with the shrinking of wetland and woodland. Spatio-temporal optimization is not a trivial task in developing landscape models. In previous studies, the optimization of spatial and temporal factors was achieved separately, because of the difficulty in formulating them together in a single model. In this study, we adapted the traditional Markov model by obtaining model parameters and neighbourhood rules from a modified genetic algorithm (GA). Model performance was evaluated between the empirical landscape map from the Landsat image and the simulated landscape map from the models. Over three simulation runs, the global deviation (GD) for the three models was 1.37, 1.10 and 1.15, respectively. This result shows that the Markov model and the GA together are able to effectively capture the spatio-temporal trend in the landscape pattern associated with urbanization for this region. The future landscape distribution in 2010, 2030 and 2050 was derived using a spatial Markov model (SMM) for further urban change and planning research. Copyright Taylor & Francis Numéro de notice : A2007-357 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160600962749 En ligne : https://doi.org/10.1080/01431160600962749 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28720
in International Journal of Remote Sensing IJRS > vol 28 n°15-16 (August 2007) . - pp 3255 - 3271[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-07091 RAB Revue Centre de documentation En réserve L003 Disponible Accuracy assessment of digital elevation models using a non-parametric approach / F. Aguilar in International journal of geographical information science IJGIS, vol 21 n° 6-7 (july 2007)
![]()
[article]
Titre : Accuracy assessment of digital elevation models using a non-parametric approach Type de document : Article/Communication Auteurs : F. Aguilar, Auteur ; M. Aguilar, Auteur ; F. Aguera, Auteur Année de publication : 2007 Article en page(s) : pp 667 - 686 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse comparative
[Termes IGN] données localisées
[Termes IGN] estimation statistique
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] modèle numérique de surface
[Termes IGN] qualité des données
[Termes IGN] résiduRésumé : (Auteur) This paper explores three theoretical approaches for estimating the degree of correctness to which the accuracy figures of a gridded Digital Elevation Model (DEM) have been estimated depending on the number of checkpoints involved in the assessment process. The widely used average-error statistic Mean Square Error (MSE) was selected for measuring the DEM accuracy. The work was focused on DEM uncertainty assessment using approximate confidence intervals. Those confidence intervals were constructed both from classical methods which assume a normal distribution of the error and from a new method based on a non-parametric approach. The first two approaches studied, called Chi-squared and Asymptotic Student t, consider a normal distribution of the residuals. That is especially true in the first case. The second case, due to the asymptotic properties of the t distribution, can perform reasonably well with even slightly non-normal residuals if the sample size is large enough. The third approach developed in this article is a new method based on the theory of estimating functions which could be considered much more general than the previous two cases. It is based on a non-parametric approach where no particular distribution is assumed. Thus, we can avoid the strong assumption of distribution normality accepted in previous work and in the majority of current standards of positional accuracy. The three approaches were tested using Monte Carlo simulation for several populations of residuals generated from originally sampled data. Those original grid DEMs, considered as ground data, were collected by means of digital photogrammetric methods from seven areas displaying differing morphology employing a 2 by 2 m sampling interval. The original grid DEMs were subsampled to generate new lower-resolution DEMs. Each of these new DEMs was then interpolated to retrieve its original resolution using two different procedures. Height differences between original and interpolated grid DEMs were calculated to obtain residual populations. One interpolation procedure resulted in slightly non-normal residual populations, whereas the other produced very non-normal residuals with frequent outliers. Monte Carlo simulations allow us to report that the estimating function approach was the most robust and general of those tested. In fact, the other two approaches, especially the Chi-squared method, were clearly affected by the degree of normality of the residual population distribution, producing less reliable results than the estimating functions approach. This last method shows good results when applied to the different datasets, even in the case of more leptokurtic populations. In the worst cases, no more than 64-128 checkpoints were required to construct an estimate of the global error of the DEM with 95% confidence. The approach therefore is an important step towards saving time and money in the evaluation of DEM accuracy using a single average-error statistic. Nevertheless, we must take into account that MSE is essentially a single global measure of deviations, and thus incapable of characterizing the spatial variations of errors over the interpolated surface. Copyright Taylor & Francis Numéro de notice : A2007-265 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/13658810601079783 En ligne : https://doi.org/10.1080/13658810601079783 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28628
in International journal of geographical information science IJGIS > vol 21 n° 6-7 (july 2007) . - pp 667 - 686[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 079-07041 RAB Revue Centre de documentation En réserve L003 Disponible 079-07042 RAB Revue Centre de documentation En réserve L003 Disponible Spatial aspects of MRSA epidemiology: a case study using stochastic simulation, kernel estimation and SaTScan / Lucy Bastin in International journal of geographical information science IJGIS, vol 21 n° 6-7 (july 2007)
![]()
[article]
Titre : Spatial aspects of MRSA epidemiology: a case study using stochastic simulation, kernel estimation and SaTScan Type de document : Article/Communication Auteurs : Lucy Bastin, Auteur ; J. Rollason, Auteur ; A. Hilton, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 811 - 836 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] analyse de groupement
[Termes IGN] analyse spatiale
[Termes IGN] épidémie
[Termes IGN] estimation par noyau
[Termes IGN] Grande-Bretagne
[Termes IGN] maladie bactérienne
[Termes IGN] simulation
[Termes IGN] surveillance sanitaireRésumé : (Auteur) The identification of disease clusters in space or space-time is of vital importance for public health policy and action. In the case of methicillin-resistant Staphylococcus aureus (MRSA), it is particularly important to distinguish between community and health care-associated infections, and to identify reservoirs of infection. 832 cases of MRSA in the West Midlands (UK) were tested for clustering and evidence of community transmission, after being geo-located to the centroids of UK unit postcodes (postal areas roughly equivalent to Zip+4 zip code areas). An age-stratified analysis was also carried out at the coarser spatial resolution of UK Census Output Areas. Stochastic simulation and kernel density estimation were combined to identify significant local clusters of MRSA (p Numéro de notice : A2007-273 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810601135767 En ligne : https://doi.org/10.1080/13658810601135767 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28636
in International journal of geographical information science IJGIS > vol 21 n° 6-7 (july 2007) . - pp 811 - 836[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 079-07041 RAB Revue Centre de documentation En réserve L003 Disponible 079-07042 RAB Revue Centre de documentation En réserve L003 Disponible Use of TRMM in determining the climatic characteristics of rainfall over Bangladesh / M.N. Islam in Remote sensing of environment, vol 108 n° 3 (15/06/2007)
![]()
[article]
Titre : Use of TRMM in determining the climatic characteristics of rainfall over Bangladesh Type de document : Article/Communication Auteurs : M.N. Islam, Auteur ; H. Uyeda, Auteur Année de publication : 2007 Article en page(s) : pp 264 - 276 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] Bangladesh
[Termes IGN] climatologie
[Termes IGN] données météorologiques
[Termes IGN] estimation statistique
[Termes IGN] image radar
[Termes IGN] image TRMM-MI
[Termes IGN] précipitationRésumé : (Auteur) Five years of data from 1998 to 2002 of TRMM-3B42 version 5 (V5), 3B43 V5, 3B42 version 6 (V6), 3B43 V6, and the Bangladesh Meteorological Department rain-gauge network were analyzed to understand the climatic characteristics of rainfall over Bangladesh. TRMM-PR 2A25 data were used to obtain the precipitation field of the convection events. Daily rainfall measured by TRMM V5 3B42 was compared to that of rain-gauge values from pre-monsoon to post-monsoon months (March–November). The time sequence patterns of the daily rainfall determined by the V5 3B42 and those from rain gauges were remarkably similar. The spatial and temporal averages of rainfall revealed good estimations of rainfall: during March to November, the V5 3B42- and rain gauge-estimated daily rainfall was 8.12 and 8.34 mm, respectively. In annual scale, TRMM V5 3B42-, V5 3B43-, V6 3B42-, V6 3B43- and rain-gauge estimated rainfall was 6.9, 6.4, 6.6, 6.8 and 7.1 mm/day, respectively. The average percentage of rainy days determined by V5 3B42 data with respect to the rain-gauge value was 96%. TRMM is useful for estimating the average values of rainfall in Bangladesh. The prominent difference between rainfall estimated by rain-gauge and V5 3B42 was found to be period- and location-dependent. The V5 3B42 overestimated the rainfall during the pre-monsoon period and in dry regions but underestimated it during the monsoon period and in wet regions. The reason for the differences according to season and locations is considered to be the vertical cross section of convection obtained by TRMM-PR 2A25 data. The rainfall overestimation in pre-monsoon and underestimation in monsoon period measured by V5 3B42 is reduced to reasonable amount by V6 3B42 and V6 3B43. In this manner, the merit of using TRMM data for climatological studies of rainfall over Bangladesh is shown. Copyright Elsevier Numéro de notice : A2007-298 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2006.11.011 En ligne : https://doi.org/10.1016/j.rse.2006.11.011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28661
in Remote sensing of environment > vol 108 n° 3 (15/06/2007) . - pp 264 - 276[article]Évaluer les choix d'itinéraires pédestres en milieu urbain / A. Piombini in Revue internationale de géomatique, vol 17 n° 2 (juin – août 2007)
PermalinkGeometric consistency and stability of consumer-grade digital cameras for accurate spatial measurement / R. Wackrow in Photogrammetric record, vol 22 n° 118 (June - August 2007)
PermalinkIndirect approach to invariant point determination for SLR and VLBI systems: an assessment / John Dawson in Journal of geodesy, vol 81 n° 6-8 (June - August 2007)
PermalinkStability of VLBI, SLR, DORIS, and GPS positioning / Martine Feissel-Vernier in Earth, Planets and Space, vol 59 n° 6 (June 2007)
![]()
PermalinkDORIS satellite phase center determination and consequences on the derived scale of the Terrestrial Reference Frame / Pascal Willis in Advances in space research, vol 39 n° 10 (May 2007)
PermalinkInfluence of ambiguity precision on the success rate of GNSS integer ambiguity bootstrapping / Peter J.G. Teunissen in Journal of geodesy, vol 81 n° 5 (May 2007)
PermalinkInteractive visualization of uncertain spatial and spatio-temporal data under different scenarios: an air quality example / Edzer J. Pebesma in International journal of geographical information science IJGIS, vol 21 n° 5 (may 2007)
PermalinkModelling landscape dynamics with Python / D. Karssenberg in International journal of geographical information science IJGIS, vol 21 n° 5 (may 2007)
PermalinkA probabilistic framework for representing and simulating uncertain environmental variables / Gerard B.M. Heuvelink in International journal of geographical information science IJGIS, vol 21 n° 5 (may 2007)
PermalinkThe topographic bias by analytical continuation in physical geodesy / Lard Erik Sjöberg in Journal of geodesy, vol 81 n° 5 (May 2007)
Permalink