연구/X3D-Earth31 DNC: Digital Nautical Chart http://www.nga.mil/portal/site/dnc/ The Digital Nautical Chart? is produced by the National Geospatial-Intelligence Agency (NGA) and is an unclassified, vector-based, digital database containing maritime significant features essential for safe marine navigation. Initial data collection of the database is from a portfolio of approximately 5,000 nautical charts that will ultimately provide global .. 2007. 6. 1. DRG: digital raster graphic http://topomaps.usgs.gov/drg/ A digital raster graphic (DRG) is a scanned image of a U.S. Geological Survey (USGS) standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator projection. The horizontal positional accuracy and datum of the DRG matches the accuracy.. 2007. 6. 1. How WGS 84 defines the Earth http://home.online.no/~sigurdhu/WGS84_Eng.html http://en.wikipedia.org/wiki/WGS84 http://earth-info.nga.mil/GandG/wgs84/ http://earth-info.nga.mil/GandG/publications/tr8350.2/tr8350_2.html 2007. 5. 19. 이전 1 ··· 5 6 7 8 다음