The seismic profile mis-ties at the intersections may be involved with amplitude gaining,time shifting,or phase rotation.

In former 2-D multi-line depth migration data processing, we often take the independent line's data as a foundation of the buildup of horizon model and pickup of interval velocity and lack control of 3-D horizon and velocity field, making the confidence level of depth -velocity model lower and there is larger mis-tie in the results in depth domain.

Model of single condition closure adjustment;

Denudation Method for Computing Independent Loop Closure of GPS Net;

The paper analyses the teaching of Engineering Survey,describes the basic concepts of error including the definitions of accident error and closure,and finally provides examples for teaching.

This paper analyzes the closure error and tolerance of the geometrical condition existing in the plane control network,and based on the production practice,introduces some methods and experiences of making the check calculation of the closure error by using EXCEL.