Centre de documentation
scientifique

Weighting function alternatives for a subpixel allocation model / Y. Makido in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 11 (November 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 11 (November 2007) . - pp 1233 - 1240 Titre : Weighting function alternatives for a subpixel allocation model Type de document : Article/Communication Auteurs : Y. Makido, Auteur ; A. Shortridge, Auteur Année de publication : 2007 Article en page(s) : pp 1233 - 1240 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] allocation [Termes IGN] analyse infrapixellaire [Termes IGN] autocorrélation spatiale [Termes IGN] classification barycentrique [Termes IGN] image Ikonos [Termes IGN] interpolation inversement proportionnelle à la distance [Termes IGN] optimisation (mathématiques) [Termes IGN] précision de la classification Résumé : (Auteur) This study investigates the “pixel-swapping” optimization algorithm proposed by Atkinson for predicting subpixel land- cover distribution. Two limitations of this method are assessed: the arbitrary spatial range value and the arbitrary exponential model for characterizing spatial autocorrelation. Various alternative weighting functions are evaluated. For this assessment, two different simulation models are employed to develop spatially autocorrelated binary class raster maps. These rasters are then resampled to generate sets of representative medium-resolution class maps. Prior to conducting the subpixel allocation, the relationship between cell resolution and spatial autocorrelation, as measured by Moran’s I, is evaluated. It is discovered that the form of this relationship depends upon the simulation model. For all tested weighting functions (Nearest Neighbor, Gaussian, Exponential, and IDW), the pixel swapping method increased classification accuracy compared with the initial random allocation of subpixels. Nearest Neighbor allocation performs as well as the more complex models of spatial structure. Copyright ASPRS Numéro de notice : A2007-514 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.11.1233 En ligne : http://dx.doi.org/10.14358/PERS.73.11.1233 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28877 [article]

Assessing alternatives for modelling the spatial distribution of multiple land-cover classes at sub-pixel scales / Y. Makido in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 8 (August 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 8 (August 2007) . - pp 935 - 943 Titre : Assessing alternatives for modelling the spatial distribution of multiple land-cover classes at sub-pixel scales Type de document : Article/Communication Auteurs : Y. Makido, Auteur ; A. Shortridge, Auteur ; P. Messina, Auteur Année de publication : 2007 Article en page(s) : pp 935 - 943 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse comparative [Termes IGN] analyse infrapixellaire [Termes IGN] autocorrélation spatiale [Termes IGN] distribution spatiale [Termes IGN] image Landsat-ETM+ Résumé : (Auteur) We introduce and evaluate three methods for modeling the spatial distribution of multiple land-cover classes at subpixel scales: (a) sequential categorical swapping, (b) simultaneous categorical swapping, and (c) simulated annealing. Method 1, a modification of a binary pixel-swapping algorithm, allocates each class in turn to maximize internal spatial autocorrelation. Method 2 simultaneously examines all pairs of cell-class combinations within a pixel to determine the most appropriate pairs of sub-pixels to swap. Method 3 employs simulated annealing to swap cells. While convergence is relatively slow, Method 3 offers increased flexibility. Each method is applied to a classified Landsat-7 ETM dataset that has been resampled to a spatial resolution of 210 m, and evaluated for accuracy performance and computational efficiency. Numéro de notice : A2007-371 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.8.935 En ligne : http://dx.doi.org/10.14358/PERS.73.8.935 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28734 [article]

Shuttle Radar Topography Mission elevation data error and its relationship to land cover / A. Shortridge in Cartography and Geographic Information Science, vol 33 n° 1 (January 2006)  

Public [article]  inCartography and Geographic Information Science > vol 33 n° 1 (January 2006) Titre : Shuttle Radar Topography Mission elevation data error and its relationship to land cover Type de document : Article/Communication Auteurs : A. Shortridge, Auteur Année de publication : 2006 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse comparative [Termes IGN] données altimétriques [Termes IGN] erreur systématique [Termes IGN] image radar moirée [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] MNS SRTM [Termes IGN] modèle numérique de surface [Termes IGN] modèle numérique de terrain [Termes IGN] occupation du sol [Termes IGN] précision altimétrique [Termes IGN] qualité des données Résumé : (Auteur) The Shuttle Radar Topography Mission (SRTM) has resulted in the construction of the first publicly available near-global high resolution digital elevation model (DEM). The utility of this DEM, as for any geospatial data set, is a function of its quality. This paper is concerned with the assessment of SRTM accuracy and its relationship to land cover. Two methods-one raster-based and one point-based-are compared to match "finished" three-arc-second SRTM data to high precision, high accuracy surveyed elevations, as well as a corresponding DEM from the USGS National Elevation Dataset (NED). Differences between the two methodologies were not found to be significant. Error for the study site is substantially less than the mission objective, but substantially more than that for the NED. Significant overestimation of actual elevations pervades the SRTM DEM, and the overestimation is significantly higher in forested areas. This systematic error has implications both for applications employing SRTM data and for research on elevation data error modeling. Copyright CaGISociety Numéro de notice : A2006-206 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1559/152304006777323172 En ligne : https://doi.org/10.1559/152304006777323172 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27933 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-06011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Lidar elevation data for surface hydrologic modeling: resolution and representation issues / C. Barber in Cartography and Geographic Information Science, vol 32 n° 4 (October 2005)  

Public [article]  inCartography and Geographic Information Science > vol 32 n° 4 (October 2005) . - pp 401 - 410 Titre : Lidar elevation data for surface hydrologic modeling: resolution and representation issues Type de document : Article/Communication Auteurs : C. Barber, Auteur ; A. Shortridge, Auteur Année de publication : 2005 Article en page(s) : pp 401 - 410 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] données lidar [Termes IGN] modèle hydrographique [Termes IGN] modèle numérique de surface Résumé : (Auteur) This paper is concerned with the application of high spatial resolution elevation data derived from light detection and ranging technologies (lidar) to surface hydrologic modeling. In recent years, airborne lidar technology bas been employed to develop high accuracy digital elevation models (DEMs) with horizontal resolution on the order of a few meters. As with any spatial data product there are limits to the lidar's practical use that vary with the intended application. This paper considers potential issues and challenges for the use of lidar-derived DEMs in surface hydrologic modeling applications, such as characterizing flow direction and power, identifying sub-basins in a watershed, and calculating upstream contributing area and other variables. We compare results using conventional 30m DEMs and 6m lidar for a high relief study area and a low relief study area. Results are more comparable between these data sources, regardless of hydrologic operation, for the high relief area, while the similarity of results in the low relief area is dependent upon the particular operation. Post-processing on the lidar data successfully removed such flow obstacles as bridges that might have artificially impeded surface flow. An exploration of the effect of spatial resolution on results suggests that cell size is a more significant factor than production method. Numéro de notice : A2005-542 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1559/152304005775194692 En ligne : https://doi.org/10.1559/152304005775194692 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27678 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-05041	RAB	Revue	Centre de documentation	En réserve L003	Disponible