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Improving National Land Cover Database estimates of road network impervious cover using vector road networks in GIS / K. Thomas in SaLIS Surveying and land information science, vol 68 n° 1 (March 2008)

Public [article]  inSaLIS Surveying and land information science > vol 68 n° 1 (March 2008) . - pp 21 - 27 Titre : Improving National Land Cover Database estimates of road network impervious cover using vector road networks in GIS Type de document : Article/Communication Auteurs : K. Thomas, Auteur ; T.A. Endreny, Auteur Année de publication : 2008 Article en page(s) : pp 21 - 27 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] ArcGIS [Termes IGN] base de données d'occupation du sol [Termes IGN] données vectorielles [Termes IGN] rastérisation [Termes IGN] réseau routier [Termes IGN] ruissellement [Termes IGN] surface imperméable Résumé : (Auteur) Polyline data are often adequate for qualitative representation of roadways for mapping and GIS yet they are often lacking when compared with surface coverages, such as raster data, for performing quantitative environmental simulation modeling where spatial representations are necessary. Widely used land cover raster data, such as the National Land Cover Database (NLCD), were however not collected with sufficient spatial resolution to allow adequate representation of small-scale features such as roadways. Using tools available in ArcGIS software, vector road files were obtained from the Accident Location Information System (ALIS) at the New York State Department of Transportation (NYSDOT) and converted to raster data to create spatially explicit representations of impervious area associated with roadways. Comparison of this new coverage with the NLCD results in an increase of approximately 3120 km2 of newly identified impervious coverage for New York State (NYS) not present in the NLCD, representing a 244 percent increase from the transportation class in the NLCD. Of the land cover that would be reclassified to roadway using this methodology, approximately 40 percent would be reclassified from forest land, 31 percent from agricultural land, and 28 percent from the residential land cover classifications. Copyright SaLIS Numéro de notice : A2008-266 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83663 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
121-08011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Official GNSS-derived vertical orthometric height control network / G. Steinberg in SaLIS Surveying and land information science, vol 68 n° 1 (March 2008)

Public [article]  inSaLIS Surveying and land information science > vol 68 n° 1 (March 2008) . - pp 29 - 34 Titre : Official GNSS-derived vertical orthometric height control network Type de document : Article/Communication Auteurs : G. Steinberg, Auteur ; Gilad Even-Tzur, Auteur Année de publication : 2008 Article en page(s) : pp 29 - 34 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] altitude orthométrique [Termes IGN] conversion altimétrique [Termes IGN] géoïde local [Termes IGN] hauteur ellipsoïdale [Termes IGN] Israël [Termes IGN] nivellement par GPS [Termes IGN] positionnement par GNSS [Termes IGN] réseau de nivellement [Vedettes matières IGN] Altimétrie Résumé : (Auteur) Since the beginning of 2006, the vertical control system in Israel has been ellipsoidal. The Survey of Israel (SOI) will not continue with nationwide precise leveling. Instead, data from permanent Global Navigation Satellite Systems (GNSS) stations are used to develop and maintain Israel's ellipsoidal vertical control system. Currently, the objective is to provide a framework on which topographers and engineers can base and adjust their heights, and this is achieved more easily by GNSS measurements. Despite this, many users of height data prefer the orthometric system, even though its control is localized. A geoid undulation model is one of the foundations of the geodetic infrastructure. It is used to connect ellipsoidal and orthometric heights. Intensive utilization of GNSS for geodetic, surveying and engineering applications necessitates the development of an undulation model. Efforts to develop such a model with an accuracy level of 1 centimeter over an entire country demand multiple resources. This paper suggests a method for developing a national, orthometric control system with a reasonable accuracy, using GNSS measurements, ellipsoidal vertical control, and an official geoid undulation model. Research was conducted in Israel in order to test the feasibility of using an official geoid undulation model. Two kinds of official models were tested: the worldwide geopotential model (GPM98B) and a local, countrywide model computed by the Survey of Israel. We compared orthometric height differences obtained by GPS measurements with the known orthometric differences. This paper presents the results of those experiments. The technique proposed in this paper was found to define seamless orthometric vertical control adequate for most geodetic and surveying purposes, at low cost and fast. Of special interest in the paper is the comparison between the proposed idea and the National Geodetic Survey (NGS) attitude toward GPS-derived orthometric heights. The advantage of using the official geoid undulation model for the acquisition of orthometric heights is demonstrated. Copyright SaLIS Numéro de notice : A2008-267 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83664 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
121-08011	RAB	Revue	Centre de documentation	En réserve L003	Disponible