摘要
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.
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.
作者
Johan Lavreau
Johan Lavreau(Earth Sciences Division, Royal Museum for Central Africa, Tervuren, Belgium)
