The research and implementation on the adjustment oriented to ground objects based on ObjectARX

Some ground objects in the digital topographic map have particular geometric features. Generally speaking, the straight lines and curves for composing roads are tangent, and the corners of buildings are usually right-angles. Due to inevitable errors during the measuring process, the original geometric features of ground objects will be damaged. In this regard, this paper puts forward to deal with the measuring errors in the contours of ground objects by using the “least-square method” to adjust, that is, the conception of “the adjustment oriented to ground objects”. It has derived out six condition equations which are common in the contours of ground objects. Meanwhile, it has proposed the processing methods to turn the tangency conditions for straight line segments and circular arc to the vertical conditions of straight line segments and to the side conditions. The paper has also developed some software basing on “ObjectARX”. After such treatment, the contours of ground objects strictly satisfy the geometric conditions.