The knowledge of the geodetic reference datum of maps or data is required for their use in a GIS. Many older maps are lacking this information, making their use cumbersome. The availability of an aerial coverage at hi...The knowledge of the geodetic reference datum of maps or data is required for their use in a GIS. Many older maps are lacking this information, making their use cumbersome. The availability of an aerial coverage at high resolution of Burundi and digital elevation model, based on a novel geodetic network, all calculated on the WGS84 datum, allows to calculate the datum applicable to older maps, for instance the regular 1/50k map of the country. The method, based on the difference in geocentric coordinates between points common to the two systems, yields: Δx = -156.71 ± 10.2 m, .Δy = -3.26 ± 13.2 m, .Δz = -290.77 ± 21.06 m, well in keeping with older values proposed by the NGA.展开更多
文摘The knowledge of the geodetic reference datum of maps or data is required for their use in a GIS. Many older maps are lacking this information, making their use cumbersome. The availability of an aerial coverage at high resolution of Burundi and digital elevation model, based on a novel geodetic network, all calculated on the WGS84 datum, allows to calculate the datum applicable to older maps, for instance the regular 1/50k map of the country. The method, based on the difference in geocentric coordinates between points common to the two systems, yields: Δx = -156.71 ± 10.2 m, .Δy = -3.26 ± 13.2 m, .Δz = -290.77 ± 21.06 m, well in keeping with older values proposed by the NGA.
