With the development of GPS real time position technology, GPS is widely used in navigation and position for moving objects such as ship and plane. The air-borne GPS data used for the skyway rectification is used to simulate the fly way, calculate the parameters, and then do the orientation rectification for remote sensing images,so as to make a base for precise geometric rectification.OMIS is an imaging spectrometer made recently by the Institute of Shanghai Technology and Physics. A test fly was conducted in Changzhou city, Jangsu province at August,1998. In this article, an experiment for skyway rectification of OMIS image using airbore GPS data is done and a good result is achived in the experiment.
Synthetic aperture radar (SAR) provides a novel technique for measuring internal ocean waves remotely in a large area. It can operate in all weather conditions and is complemental to traditional measurements. The procedures are given in this paper for extracting wavelength and wave direction of internal waves by using Fourier analysis and wavelet analysis methods. A ERS-1 SAR imagery of South China Sea is analysed in this paper.It is shown that Fourier analysis is capable of calculating the wavelength and wave direction,and the wavelength calculated from Symmlet and Daubechies wavelet analysis show good agreements each other. An approach to remove the 180°ambiguity of wave direction is also given in this paper.
Administrative border is one of the most important constituent parts of the national basic geography information. The application of the fruits of the demarcation and the development of the Administrative Border Information Management System (ABIMS) not only are significant for the administrative border management, but also can greatly propel the construction of the Chinese Digital Earth.
A theoretical model of two-dimensionally periodic medium is introduced for SAR remote sensing data.The region under ground surface is modeled as half space of two-dimensionally periodic medium.Because the polarized direction of the electromagnetic eigenvector in two-dimensionally periodic medium are not necessary the same as that of incidence,the scattering fields in free space is generally arbitrary polarized.Therefore,both like and cross scatters can be considered by this model.The simulation results of dependence of incidence direction,polarization and frequency,in addition to the complex permittivity of ground,are presented here.With relatively simple parameters,this model has wide potential usage.The numerical simulation based on the model can show almost all aspects of multi-band multi-polarized SAR remote sensing data.This model is specially suitable for surface parameter inverse problem based on SAR remote sensing data which kind is very limited.
The updrafted Snowmelt Runoff Model(SRM) was applied to the daily snowmelt runoff simulation of Manas River based on the spring snowcover monitoring of Tianshan Region by using the NOAA/AVHRR satellite data.The results showed that the coefficient of determination of the simulation could reach 0.89,and the deviation of the runoff volumes was within 5.1.If the parameters can be adjusted according to the method described in this paper,the model will be easily used to the similar basins.
The rapid land use changes result in the difficulties in timely updating the information of land resources using traditional methods. In order to resolve the difficulties, this paper discusses the principles and methods for dynamic monitoring land use changes and timely updating the database of land resources using the technology of remote sensing (RS), geographical information system (GIS) and global positioning system (GPS), which are also called‘3S’technology. Remote sensing is used for change detection of land use, GPS for locating the detected change areas with accurate position data, and GIS for establishing the spatial database of land use and for further analysing and updating the data. A real computer system for the above purpose is established for Fuqing County of Fujian province, China, based on the‘3S’technology. The system possesses the functions of dynamic monitoring land use changes and timely updating the data of land use as well as the functions of a general database manage system.
To evaluate the runoff volume available for agriculture irrigation in the loess plateau semi-arid area of China,six catchments were studied by means of GIS and RS method , and a rainfall-runoff model based on the parameters obtained by the GIS and RS was developed. These parameters are NDVI derived by the NOAA satellite images,area of catchments derived by the DEM of this area, average rainfall and runoff amount collected from the government hydrological stations. The multiple regression method was used to analysis these data . The calculated result by this model fits very well with the observed data in a experiment spot. So we think this model can give better result in calculating the runoff volume than the runoff contour method.
The ocean field will become one focal field which human will contest for and develop in the 21th century.It is one of international important study front projects to forecast offshore oil and gas resources by integrating remote sensing approaches,geophysical approaches,geochemistry approaches,radiation approaches,and so on.The authosrs mainly introduce one integrated system for forecasting offshore oil and gas resources and one of its core modules in Marine GIS.In the paper,its envionment of software and hardware,work flow,system structure and function of modules completed are respectively described.At last,the authors conclude the system about its development and application.
The quantitative method has been applied to research by more and more researchers with remote sensing data recently. We also try to apply the quantitative method to study forest fire. In this study, a model was developed to identify small burning spots automatically by using multivariate analysis. Experiments showed that this model could reduce the interference from cloud and boreal land. So it can increase the precision of monitoring small burning spots to some degree.
Techniques for data fusion in multisources remotely sensed imagery are reviewed.Representation of information,framework,algorithms,control and applications of fusion are included.Problems,possibilities and prospects of data fusion are discussed in conclusion.
Gaussian Mixture Density Modelling and Decomposition (GMDD) is a hierarchical clustering method based on robust statistical theory. Firstly, GMDD is assumed with a mixture group of Gaussian distribution in feature space, then by optimization algorithm the feature which mostly accord with the assumed distribution is hierarchically extracted from space until all of the features in the space are decomposed to a group of featuring pattern. Compared with conventional statistical clustering methods, GMDD' s main outstanding superorities are:(1)Initial number of features does not need to be specified a priori; (2)The proportion of noisy data in the mixture can be large; (3)The parameters estimation of each feature is virtually initial independent; and (4)The variability in the shape and size of the feature densities in the mixture is taken into account. The article presented the model named the GMDD based remote sensing image feature estimation model (GIFEM) , and the model of GA space searching optimization is also presented out.
From the contemporary developments of remote sensing and 3S(GPS,GIS and RS)integrated system,this paper introduces some main techniques in remote sensing image understanding field,they are:(1) ground analysis,including analysis of geographical elements in a certain area,relationships between them
and their integration in aspects of spatial distribution features and temporal changes;(2) knowledge acquisition,which lays special stress on knowledge acquisition from GIS Database;(3) credence research,including the determination of the elementary unit for image understanding and utilization of various data.Accordingly,it discusses image segmentation and data fusion respectively;(4) analysis of knowledge base building,including tradeoff making between generality and practicality in building knowledge base;(5) integration of RS and GIS,which specially discusses the soft interface between RS and GIS.For designing this kind of expert system,some key ideas such as integration of GPS,GIS and RS,formation of knowledge base system,application model building etc.are also discussed in this paper.
There are many areca trees planted in Taiwan for economic reason. But the areca will do great harm to environment and people' s health, and it will lead to slope erosion for its shallow root, so the planting of areca must be controlled. Remote sensing provides a useful means to monitoring the planted area of areca. But the planted densities of areca are usually low, it is difficult to identify the arecas by ordinary methods even in high ground resolution remote sensing images such as SPOT. Linear spectral mixture analysis is a method to look a pixel as composed of many different kinds of endnumbers, and it can calculate the proportion of each kind of endnumber in each pixel, so it is useful to identify the small objects in the images. In this paper, linear spectral mixture analysis is used to calculate the density of areca. Some countermeasures were put forward to make up the shortcoming of less spectral resolution of SPOT images.Then the result of linear spectral mixture analysis was compared with those of maximum likeness classification and extraction by threshold. It can be found that the result from linear spectral mixture analysis can not only extract the correct area of areca, but also calculate its density, and it is much better than those of other two methods.
With its all-weather,all time capability,radar remote sensing has great potential for agricultural application.A case on multi-temporal ERS-2 SAR images using in crops classfication was presented.Image temporal selection was based on backscattering characteristics and rotation practices of the major crops in the study area.Study on a series of preprocessing techniques on multi-temporal ERS-2 SAR Images,including calibration,geometrical correction and speckle reduction was introduced before they could be used later with accuracy.
The control of total mass for the land-based pollutants discharged into bay is important one of method for marine protection in China,and also important for restoring environmental quality.In this paper,the marine geographical information system for total mass control of the land-based pollutant discharged into bay was finished with GIS platform of ARCVIEW and ARC/INFO in example of Dalian bay in the Liaodong Peninsular.By this system we can undertake management of social and economic information in bay area,analyzing of industrial and subsidence contamination along shore,management of marine environment data from different source,modeling of marine water quality.As a result,the system integrated dynamic model and pollutant disperse model.
GPS satellite surveying technique is an important stone mark in surveying and mapping history.Building and developing LADGPS and WADGPS are effective means of improving GPS real time positioning accuracy .Using GPS receivers on ground points and in plane to adapt proper method, which can satisfy the needs of accuracy for aerial triangle survey on several scales .At present, the technique of RS、GIS and GPS integration is an important contents of geomatics researches. The comprehensive utilization of three technologies consists of a processing system of overall, real time and dynamic for earth observation,analysis and application.
