The Research And Practice Of Spatial Datum Transformation For Basic Geographic Information

Spatial datum of geographic information plays an important preceding basic role in surveying and mapping and socioeconomic construction.With the space geodetic surveying technology developed, the kinds of spatial datum become more and more.So, the transformation between different spatial datums have become especially important.This article mainly discussed the conception, formula and model of geographical reference system, the main researches of this arttical are:1. Introduced the technology of spatial datum transformation and the apply history of geodetic datum in China and other countries around, then analysed the basic data of test area ,such as topographic maps,geodetic control point for experiment.2. Introduced the algorithm and formula of spatial datum. Discussed Bursa―Wolf model, Molodensky model, Wuce model and simplification model, based on introduction of basic formula of geodetic coordinate transformation.Then introduced vertical fitting model basedon classification of vertical datum.3. Discussed the applicability of transformation model between the geodetic space coordinate systems. Compared and analysed the transformation models, introduced the method of parameter solution. Discussed vertical fitting model and improved these models.4. Combined with condition of region, practiced the spatial transformation models and conversion algorithm. Soluted the transform parameters, Combine with the applicability of transformation model, analysed the precision.At last, discussed the stability of transform parameters and sources of error.5. Combined with condition of region, discussed vertical fitting models refer to this article and explained the accuracy and applicability. Compared and analysed the precision of vertical fitting models, introduced leveling grade of vertical fitting model,based on the evaluation of precision.