Geographical information system(GIS) are drawing more and more attention in the field of underwater topography analysis because of the powerful spatial analysis and spatial database management.

Following an example of practical large scale underwater topography survey, the operation process is demonstrated and some data are analyzed.

The underwater topography in the Prydz Bay is rugged and rough.

Compared with modeling on ground terrain, modeling on underwater terrain is a converse process.

At present, dredging and harnessing of the rivers and lakes is one of the national major projects which are pushed on by government, and underwater terrain survey is an important measurement means.

A simulation model for the radar backscattering cross section of the sea surface has been developed based on the radar imaging mechanism of underwater bottom topography.

Based on Bragg scattering theory, the three dimesion model for the synthetic aperture radar(SAR)imaging of underwater bottom topography in the tidal waters is presented in the paper.

There is important actual meaning in how to raise the sounding precise of bathymetric surveying.

on the basis of analyzing all-round the present situation and the existing problems of monitoring system for dynamic state of groundwater in Jilin Province,by the comparison and analysis among abroad and domestic monitoring systems for dynamic state of groundwater,the authors put forward planning scheme of monitoring system for dynamic state of groundwater in Jinlin Province in this paper .