期刊名称：American Journal of Geographic Information System
印刷版ISSN：2163-1131
电子版ISSN：2163-114X
出版年度：2018
卷号：7
期号：4
页码：107-117
DOI：10.5923/j.ajgis.20180704.02
语种：English
出版社：Scientific & Academic Publishing Co.
摘要：A high accuracy Digital Elevation Model (DEM) for the Nile delta region, Egypt is needed for several environmental applications, particularly for investigating the hazardous impacts of sea level rise and land subsidence phenomena. Since there is no official published national DEM for Egypt, an original high accuracy local digital elevation model (LDEM) for that region has been created using nine Spatial Interpolation Methods (SIMs) within a Geographic Information Systems (GIS) environment. The interpolation process took place after digitizing over than 220 topographic maps of scale 1:25,000, where more than 810,000 elevation (spot heights) points have been extracted from these maps. Multiple parameters and criteria for each SIM were applied to reach the optimal settings to produce a LDEM for environmental applications. The developed LDEMs have been compared against eight free Global Digital Elevation Models (GDEMs) using about 200 known GPS/levelling Ground Control Points (GCPs), where a statistical assessment has been accomplished for both GDEMs and LDEMs residuals after applying a vertical and horizontal datum matching for all the used data sets, and an outlier detection procedure. Also, a Reliability Index (RI) has been calculated to determine the best DEM for the Nile Delta region. The accomplished results showed that EARTHEnv-DEM90 attained the highest RI of 5.47 as the optimum global DEM. For local DEM's interpolation methods, it is concluded that the Kriging-based local DEM attained highest RI of 9.27. Consequently, it has been concluded that the new developed high accuracy LDEM improves the overall accuracy and reliability of the best available GDEM by almost 41%, and, hence, it is appropriate for geospatial, environmental, and GIS studies in Egypt.
关键词：Digital Elevation Model (DEM); Spatial Interpolation Methods (SIMs); GPS/levelling; GIS
