平面坐标和高程系统综合为三维坐标系的原理、方法与应用

In order to integrating horizontal coordinate system and elevation system into an true three-dimensional coordinate system, this researching item proposes for the first time a new method for determination through many - points by which the regional ellipsoidal surface is more coincidental with the projection surface by means of readjusting orientation and positioning of ellipsoid and further optimizing the elements of ellipsoid, so that the geodetic height is appropriately equal to normal height. Meanwhile , the proposed geodesic coordinate measured in meters, rather than in degrees are applied to express the position on the ellipsoid..Some strict definitions and demonstration in many ways of geodesic coordinate system are given .The validity of expressions and algorithms has been demonstrated by data examples. Compared with geodetic coordinate system, it can make complex computations on ellipsoid easily, because its expressions of distance and angle are similar to expressions in plane, moreover, its precision is quite high..Based on geodesic coordinate system,this item proposes the principle and method of ellipsoid-based DTM, which is different from DTM based on Gauss projection plane because the projecting distortions from ellipsoidal surface to Gauss plane do not exist in it.. Furthermore, the item presents a 3dGIS visualizing model based on ellipsoid and realizes the principal entities models such as road model, lake model, building model etc. especially connected with road design .The approach realizing entities models is to overlap ellipsoid-based DTM and spatial entities..On the while, the paper presents a new way for theory and application of GIS.

基于最优化区域椭球面的设置将互为独立的平面坐标和高程系统纳入到一个完整的三维坐标系，这不仅有利于用GPS测定正常高及为三维GIS采集数据，且能满足大区域中为客观反映三维空间现象几何特征对参考系的要求。探索此三维坐标系在三维GIS及CAD中的应用，侧重于研究能用于立体线形设计和景观设计的三维设计模型及信息系统。