1992 Vol. 17, No. 2
This paper has derived the quasi-point mass model of Integrated Geodesy by using the Quasi-point mass method of local gravity field. The observation equations of terrestrial geodetic measurements, GPS levelling data are given in this case. Finally the relevant questions have been diseussed.
This paper presents a computer vision based thematic map reading system. It gets images from CCD camera. The thematic map is automatically read through a series of data processing procedure, such as line following, arc vectorization, to pological sturcture generation, data compression geometrical rectification, mosaicing and so on. In this system, areas and lengthes are measured automatically and statistical information are generated for the thematic data base.
After a briefly review of the history of GPS positioning, this paper raises a new concept of the operation modes for GPS positioning. For a clear understanding, WILD GPS System 200 has been taken as an example to explain the most usable operation modes which are available for the time being.In this paper, author also points the principle and the way to select the most suitable mode for a specified job. None would deny such an opinon that it is an urgent task not only for manufacturers but also for users to perfect various operation modes existed and to develope new operation modes with higher efficiency and wider application for GPS positioning.
In this paper, the aspects of accuracy, reliability and sensitivity of an engineering control network are systematically disscussed. It is proposed that a monitoring network should take the sensitivity as the pricipal quality criterion in network design.With a specified deformation model, a computer aided monitoring network design system (CAMNDS) concerning the quality criteria of sensitivty, reliability and economy is developed. In the system, the main judgement for modifying the design is the sensitive elements. Therefore it has both analytic nature and computer aided simulation nature. The system can also be used in the design of general engineering control network. Finally a typical example is given using the system and some useful conclusion are drawn.
In this paper the synthetic fracture criteria has been applied to threedimensional medium. The conditions of the application of the synthetic fracture criteria to the crace extension under combined stress in three-dimensional have been given by the analysis and comparison of the theoretical solutious and the experimental results. The test results under mixed mode Ⅰ-Ⅱ, Ⅰ-Ⅲ and Ⅱ-Ⅲ fracture are compared with the theoretical curves predicted by four difterent fracture criteria.
This paper has analysed theoretically the problems at the key link sin the procedure for elevation exfraction using SPOT imagery by means of fully digital approach and the proposed methods which are necessary and flexible. The mathematieal model of time-sequantial exterior to the geometric characteristics of SPOT imagery. It is very important to chose the precise control points and the reasonable preliminary value of exterior orientation elements of central line and to calculate the equivalent focal length. The iterations for calculating the elements must be performed for the solutions of linear elements in one time and angular elements in other time, i. e. no solutions for both at the same time, just as the case in aerophotogrammetry. New approaches should be taken for data organization, avoiding the loss of precision during the interpolation of elevation after automatic correlatcins. According to satellite image characteristics,a strategy of multi-level matching are realized to improve the precision and the reliability, for which it is important to introduce the modified high accuracy least square matching algorithm. The results of the DEM generation using SPOT image windows in Marseille area show us that they can reach the elevation accuracy of 10m when the image quality can be assured.
In the research, 1200 evaluating units are bivided in the case study area-Wuchang Proper. Starting with social-economie factors which influence land value, 19 multil—evel and multi-factor indexes are selected according to Flourish Degree which indicates the amount of the social investments. The evaluating data are obtained based on combining aerophotograph interpretation with field check and the corresponding quantifying methods for each index are presented, And on the basis of those quantified indexes, urban land grading in Wuchang Proper has been finished by using Level-Composite Judgement Method on computer, The final results present that the method,is reasonable.
The national primary GPS network (NAGNET), covered the whole contint and prinicipal islands of China, has been desiged and the observation campaigns have being carried out, conducted by the National Beauru of Surveying and Mapping. This paper discusses several technical problems for the establishment of the NAGNET, including the gaols and significance, accuracy standards and techinal schem of the network,the technical elements of both obsevation and data processing, and some aspects for application research and development Finally, several recommendations are given for the project.
In the paper, on the basis of known major atmospheric parameters, for example, air and underground temperature, amount of raintall, etc, how to use the method of time series analysis to process the data of observation across fault is emphatically disscussed. Through two practicality, detailed research about constructon of mixd linear regression equation, the relation between the model equation and the earthqake anomaly, processing and analysis of the observational data with possibly has anomaly is made. Besides, the grey dynamic data model that the residual is adjusted by GM (1,1) is given.Through practicality, it indicates that the metod mentioned will show its advautages in data proessing of deformation measurements across fault.
In this paper, a mathematical model for the election and evaluating of basic cartographical material is established, on the basis of the multi-layer Fuzzy symthatie evaluating. An example is given which shows that the model is applicable and precise.