Reliable and Practical City Map generation at 1:1000 or 1:500 scale based on “Five control points" recification of digitized images
Using high resolution image for making city map by digital rectification is simple.But five control points can correct image deformation precisely and reliable are not easy particular making 1:500 scale street view map. Nowadays, RTK-GPS becomes the definitive mapping instrument to draw 1:1000 scale maps but get some shortages. That are,
1. Operators can’t have an overall impression of the mapping place.
2 Measuring points are separate so that the lines are not natural and smooth.
3. Data transmission may have 0.1 % mistakes which waste time to check and are troublesome. Given method comes as a substitute, which keeps all advantages and use RTK to definite the key points for drawing. Here are three examples for reference. The map size are extremely large and beyond the custom. (area; 60cm×70cm,80cm×180cm, 60cm×200cm) Which without any splices.
The interpolation for rectifying is surface splines which were originally developed for interpolation wing deflections of aircraft; Surface splines are a mathematical tool to interpolate a fuction of two variables. It is Base upon the small deflection equation of an infinite plate. The main adtvantages of the surface splines are that the coordinates of the known points needs not be located in a rectangular array and the function may be differentiated to find slopes. (Contributed by Harderand Desmarais 1972)