The Belgian Soil Map and GIS: a preliminary treatment to operate the geometric ability between the soil map and the basic topographic background [ArcInfo]
1995
Lejeune, P. (Faculte Universitaire des Sciences Agronomiques, Gembloux (Belgium). Dept. Environnement, Territoires, Nature et Forets)
Almost half (40) of the sheets of the Belgian Soil Map (scale 1/20,000) has been produced on a topographical background showing geometrical differences, sometimes important, with the basic topographic background produced at present by the National Institute of Geography. Twenty percent of control points georeferenced on a test sheet show differences higher than 80 meters between the two reference systems. A simple method is proposed to match up inaccurate sheets of the soil map with the basic topographic background and to reduce these differences. It is based on control points evenly distributed on the sheet to be corrected and georeferenced in the two systems. A translation is applied to the points digitised on the soil map, corresponding to a weighed mean of the differences observed on the nearest control points, the weighing factor being computed on the basis of distances between control points and the element to be corrected. This procedure is integrated in a program running on a PC in Arc/Info environment. The entire correction process (identification of control points, preparation of files, program execution) takes less than three hours per sheet.
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