Data Processing Of C-level Control Network In Tongyu County

To ensure the unified surveying datum used in the survey of rural collective construction land and house in Tongyu,Bureau of Land and Resources of Tongyu decides to establish a C-class control network throughout the county.This research establishes the CGCS2000 Coordinate System by contacting and adjusting IGS station and establishes connections between the CGCS2000 Coordinate System and the XA80 Coordinate System by using the plane four-parameter model.The quasi-geoid of the survey area is based on EGM2008 Model and the Remove-restore Method.The compensation coordinate system of the survey area is established by moving central meridian and changing the projection elevation plane.The ultimate data processing result shows that the point position error in the CGCS2000 Coordinate System is less than 1 cm and the coordinate conversion error between the CGCS2000 Coordinate System and the XA80 Coordinate System less than 1cm.The error of quasi-geoid fitting in the survey area is better than 10 cm while the comprehensive deformation of length projection in the compensat ion coordinate system of the survey area is less than 2.5cm/km.The data processing result formed in the C-class control network,which meets relevant requirements,can be used in the survey of rural collective construction land and house in Tongyu as well as other surveys.