Of Gis Center Line Position Uncertainty Model

Geography information system (GIS) are special information system that are used to capture, store, manipulate, retrieval and analysis the all or part surface of the earth and the space. In GIS, the quality of spatial data affects the applicability of data and the reliability of applications directly. Hence, the quality of GIS spatial data, especially the uncertainty of spatial data, is becoming more and more important. For the studies of GIS uncertainty, error band model of a line segment is one of the current focus issues, which reason is not only that there are many open questions for the uncertainty of line segment but also that the uncertainty of line segment is the base of both the uncertainty of the surface element and GIS spatial analysis. The thesis studies the error processing of map digitized data and the uncertainty of line segment in GIS based on the theory and experiment, especially focus on the establishment and the derivation theoretically of the uncertainty models. The main results are as follow:(1) Presents a study on the error processing of map digitized data with nonlinear least square adjustment which is called damped least square method. In the processing of the bigger errors, the damped least square method can reduce the model error in the linearization process of the condition equation and then can improve the calculation accuracy.(2) Studies the geometrical shape of error band for GIS uncertainty mode of two-dimension and three-dimension line segment. Based on the monotone and extreme theory of function, we prove the geometrical shape of error band for line segment modeltheoretically, and obtain the minimum and its position of error band mathematically.(3) Constructs an error entropy model for spatial linear positional uncertainty based on the point of information entropy. The model is composed of a cylinder and an error ball. The cylinder radius is the error entropy in the plane perpendicular to the spatial line.(4) Develops an uncertainty model for three-dimension circular curve in GIS based on theuncertainty and statistic theory. The band of the model is composed of a group of errorellipses, which are in the plane perpendicular to the tangent of the point on the spatial circular curve, and the part error ellipsoid of the extreme point. And the centre axle of the band is theoriginal circular curve.