2008 Vol. 33, No. 2
Informatization of surveying and mapping is the certain result of digitization of surveying and mapping.It will influence the development of all branches of surveying and mapping in spatial data collection,data processing,integration,management,representation,application and service providing.The intension,basis of development,the core of informatization system,the change of produce organization and the motivation of development of informatization of surveying and mapping from the point of view of photogrammetry are discussed.
The split-window algorithm proposed by the authors is improved.In order to evaluate the practical effect of the algorithm,the analysis of influence of water content on the transmittance is made and the results indicate that the algorithm is not sensitivity to water content.In order to confirm the conclusion,the authors retrieve the land surface temperature through change the water content retrieved from MODIS data and get similar conclusion.All the results show that the algorithm is practical and not sensitive to water content.
A radar coherent scattering model for forest canopies based on fractal-generated trees and forest dynamics models is established.In order to obtain the position of scatterers,the fidelity of forest structure is simulated by two models: forest dynamics and fractal-generated trees model.Forest dynamics model,ZELIG,can get stand structural composition in some ages.A fractal-generated trees model,L-system,can simulate a 3D tree.Every scatterers are obtained by linking up ZELIG with L-system.Radar coherent scattering model simulates the information of radar backscattering by output of ZELIG and L-system.The prediction results of coherent model is validated by the JERS-1 SAR and Envisat ASAR data from the pure birch of Changqing test site in Daxing'anling.
A new approach for object identification based on the exhaustive method is proposed.Each pixel spectrum in the hyperspectral imagery has an optimal matching spectrum selected from all possible reference spectra that are correlated with the study area.The selection is done by computing the maximal angle cosine or correlation coefficient.Thus,identification maps are created by the identification results of all pixels.Some reference spectra are changed against the information in the maps to obtain better identification results.This approach is applied to a hyperspectral image of the peripheral area of Pulang porphyry copper deposit,Zhongdian County,Yunnan Province,China.The results show that this method is effective and practical.
The method of establishing the point spread function(PSF) of motion-blurred image is discussed.For linear motion blur,it is proved that the two dimensional PSF must be established directly in the motion direction,instead of decomposing to two axes or rotate to the horizontal axis.Then an algorithm is presented to estimate the two key parameters of PSF: establish the cepstrum of the motion-blurred image and find the minimum of it,the location of the minimum gives the information of blur range and blur direction.Experimental results show that the method can guarantee a small error a good quality of restoration when blur is at arbitrary direction and between 5-55 pixels.A big error occurs when blur range is out of 5-55 pixels.
A new filtering algorithm for InSAR interferogram is proposed.First,the raw intergerogram is mapped to unit vectors.Then the vectors are decomposed to two parts: the sine signal and the cosine one.Secondly,the sine and the cosine signals are filtered by wavelet threshold method.Finally,the filtered interferogram is calculated by the filtered sine and cosine signals.In order to evaluate the precision of filtering,a new evaluation method is presented,which uses the RMS of the phases between interferograms before and after filtering.Different types of interferograms are employed in experiments.The results show that the proposed filtering method is valid.
A new adaptive method of image de-noising based on two-dimensional wavelet transform and independent component analysis(ICA) is presented.It does not need a lot of observed image samples,and it is not necessary to know the details of the observed image signal type in advance.A single observed image could be de-noised by this method adaptively.The principle of ICA virtual observed noise channels de-noising and two-dimensional wavelet transform constructing those channels are introduced,and the experimental results based on this method are given.The results show that by using the proposed method the hybrid noise is removed effectively and the image details are protruded and the image quality is improved.
A PBIL algorithm is presented to match remote sensing images.It uses the strategies of genetic operation and competitive learning,modifies the learning probabilities according to competitive learning,and then supervises the offspring generation.The detailed academic and experimental analysis are introduced,and the information entropy as one of the iterative terminated conditions is put forward.Experimental results show that this method is effective and fast,and the convergence procedure is stable.
The components of geo-ontology and its hierarchical structure are analyzed,and the design method for sedimentary-ontology is presented,which is an important application case of stratum-ontology.Through the definition of stratum-ontology,the analyses of attributes of its application ontology,and the selection of described attributes of application ontology,the semantics contents and semantics relations of stratum-ontology are discussed,and the Backus Naur Form(BNF) description method for stratum-ontology.With the strata connection of Zhangxia group in the boder of Jiangsu province and Anhui province,the case of sedimentary-ontology and its applications in borehole data integration and strata-relation judgment are introduced,which gives a preliminary introduction to the study of geo-ontology and its application in geosciences and geo-engineering,especially in regional borehole date integration for digital mine and digital geology.
A knowledge-based decision support system model for site-selection completely according to the process and character of site-selection is provided,the knowledge representation and acquisition,and reasoning strategy are discussed,decision-tree to partly realize automatically knowledge acquisition is introduced.The frame and design of spatial decision support system for site selecting roundly is discussed,including decision target creating,suitability reasoning and decision reasoning.An Ecological Park' SDSS for site selecting is implemented with the deep-coupled integrating mode.A case study of site-selection analysis for an environmental-friendly agricultural project demonstrates the approach.
A new evaluation model for the accuracy of digital elevation model is built based on the reconstructed contours.By the model,the accuracy of digital elevation model can be evaluated by the proposed reconstructed error that is the ratio of the area error between the reconstructed contour and the original contour to the length of original contour.The proposed error is unique.Compared with the root mean square error,the proposed method to evaluate digital elevation model is more reasonable and more reliability.
Quantitative measure for map information is a key issue in spatial information sciences.Effective quantitative measure methods are not only important for understanding characters of spatial information,but also important for effectively use of these information.Among different kinds of maps,topographic map is broadly used in many fields.The landform is usually characterized by topograhic contour lines on this map.Existing quantitative measures for map information are evaluated.A set of quantitative measures for geometric and topological information of topographic contours is proposed.Some tests are given.
Compared to the general 3-D Douglas-Peucker algorithm put forward by the authors in the previous publication,further improvements and expansion of the algorithm are discussed.Experimental results prove that these measures can greatly heighten the efficiency of the DEM generalization with satisfactory results,and offere us the practical possibility of on-the-fly global generalization of DEM with huge volume of data.
The abundance and quality of natural resources influences the regional society and economy development,so the evaluation of natural resources is essential for regional analysis and programming.Gray clustering model uses the clustering function with co-origin and subsection.In order to evaluate the natural resources,the clustering element is partitioned into many categories via weight.The natural resources in Hubei Province are evaluated.Compared to other methods,gray clustering model not only improves the sensitivity of this method and utilization of information,but also has other characteristic such as impersonality and sententiousness.
The principle,method and application of spatial points clustering based on self-organizing neural networks are studied.A kind of composite clustering statistic,called generalized Euclidean distance is proposed,which is calculated by both geometric and semantic characters of spatial points.Self-organizing spatial clustering based on generalized Euclidean distance can generate better result reflecting the clustering characters of spatial points.A case study to probe into data classifying,gross error detecting and homogeneous areas partitioning using self-organizing spatial clustering result is employed.
The enhanced VRS network utility solution software(VENUS) is presented,including the structure design and module function realization of real-time kinematic(RTK) positioning.The software VENUS is currently on the service in Sichuan integrated GPS observation network(SIGN),China.The performance evaluation shows it can achieve better than 2-3 cm accuracy in horizontal position and 2-4 cm in the height within the network coverage area.
A united combined bias model based on nu-SVR is put forward,which uses the information of all base stations in the network RTK.This model is used to train and predict by using the data from a network RTK which have six base stations.The result shows that this model is useful and efficient.
To solve the problem of colored noise filtering to do the precise dynamic positioning(or navagation) by use of the three phase difference of GPS carrier waves.The linear filters with dynamic colored noises and observational colored noises are derived and it may be proved that the Kalman filtering with dynamic white noises is the special case of Kalman filtering with dynamic colored noises,the Kalman filtering with observational white noises is the special case of Kalman filtering with observational colored noises.
The formulas of the fixed parameter sequential adjustment with constraints are conducted detailedly,and the characteristics of this method are analyzed.The robust sequential adjustment with constraints to deal with the data in which there are some outliers is alsodiscussed.Two examples are given to show that the formulas of the sequential adjustment with constraints among parameter are correct and effective,and that the robust sequential adjustment with constraints can effectively control the influence of the outliers.
The problems encountered when using Kalman filter for satellite precise orbit determination are discussed.And a new nonlinear adaptively robust filter is proposed.Firstly,the new method uses nonlinear filter to improve the orbit's precise,avoiding the bad influence of linearization error to orbit results.Secondly,bi-factor variance expanding model is used to adaptively adjust the covariance matrix of measurement noise,and resist the bad influence of measurement outliers to orbit results.Thirdly,an adaptive factor is used to adjust the covariance matrix of state noise,and reduce the bad influence of state model errors to orbit results.An example of CHAMP satellite orbit determination is given,and the result demonstrates that the new method is feasible and effective.
An adaptive filtering for GPS/INS integrated navigation is designed,considering the influences of stochastic errors.An improved BP neural network learning algorithm is set up,on the basis of it,a new GPS/INS adaptive filtering that combines the adjustment of stochastic errors and systematic errors is put forward.The results prove that the algorithms are valid and reliable when applied in GPS/INS integrated navigation system.
GPS can provide high accurate timing scale,but the common GPS receiver can only provide timing scale of second pulse which can not suffice the demand of navigation,electronics,and power transmission which need high accurate timing scale of higher frequency.How to provide high accurate short timing scale is the linchpin upon which these departments use GPS to provide time.High accurate short timing scale using GPS and FPGA based on this point is designed.The system does some theoretic and digital analysis from crystal veracity to timing precision,adoptes a series of measures considering from means to design and ensures the precision of timing.
In order to weak the effect of the representative error of sound velocity profile(SVP),a new method,which is used for constructing spatial model of sound velocity and completely reflecting spatial structure of sound velocity,is studied.Two methods for building the local spatial model of sound velocity are given.One is that the model is constructed with SVPs;the other is that the model is constructed with temperature profiles and salt profiles.Both of the two methods can achieve very consistent accuracy and reach about 0.2 m/s in the construction of spatial model.The method is proved to be credible and feasible by an experiment.
The research background and the workflow of gravity matching navigation are introduced.Simulation model,which employes the true gravity anomalies data on the Chinese coastal waters,is designed by two different algorithms,multiple model adaptive Kalman filter and the method of the absolutely difference's square.Simulation testing is implemented in two routes that have different changing magnitude in the gravity anomalies.And satisfying results are obtained.It is testified the technological feasibility of gravity matching.
The sea surface height abnormity time series in South China Sea region,are analyzed by wavelet multi-resolution technique.The linear analysis results show that the sea surface height in the region raised about 94.1 mm in 9.86 a.The seasonal variabilities of SSHA from 2 a to 45 d show that the general characteristic of the SSHA fluctuations.
The data combination techniques are applied on the basis of the least square method,and some details are presented: the influence of choosing common points on transformed parameters;how the transformed parameters change with the number of common points;the dissimilitude of precision between 6-parameters transformation and 7-parameters transformation.In addition,the unified self-constrained velocity field in continental China and its adjacent area and peripheral area using GPS observations from 1997 to 2005 are estimated,and the unified velocity field of this area's present-day crustal movement is obtained.
Dynamic multi-objective TSP(DMOTSP) is an NP-hard problem which comes from the applications of mobile computing and mobile communications.The problems of measuring the degrees of dynamic change and conflict between objectives are studied,the measure methods for them are first proposed,which can be used to compute the degrees of dynamic change and conflict between objectives.