1998 Vol. 23, No. 4
The development of surveying and mapping as well as its key sub-disciplines is analyzed. Also the theoretical basis and application of the fundmental sub-disciplines in the discipline "Geomatics" are discussed. By comparison the result shows that the development of "surveying and mapping" in the information era is "Geomatics". Some new terms about the discipline "Geomatics" are given. In author's opinion, "Spatial Information" or "Spatial Information Engineering" can represent the characteristics of future development of surveying and mapping.
In China, the government will establish spatial data infrastructure (SDI). This paper introduces some main ideas for producing and establishing the digital geospatial data framework consisting of digital orthoimage maps, digital elevation models, and vector data including road, water system, boundary of adminstrative division and place name annotation. Then the paper introduces the hardware, software and some requirements for implementing the DGDF.
This paper provides the so-called method "equivalent frame photograph (EFP)" for bundle adjustment from space using three line scanner imagery. The tie points from the CCD images which coordinates have to be transferred to the EFP. The conventional collinear equations and smooth condition about the exterior orientation elements are selected as the mathematical model for adjustment. Some adjustment results using simulated data are made. Finally the possibilities for topographic mapping with contour interval 20m are discussed.
The achievements in the research of the earth's gravity field and in training corresponding qualified scientists and technicians of Wuhan Technical University of Surveying and Mapping are reviewed in the paper. Moreover, some suggestions for developing the earth's gravity field approximation theory and training corresponding skilled personnel are presented.
The integrated adjustment for national high precision GPS A-order network is carried out in different precepts; and the way of using nationwide high precision GPS network to process and analyze data of the lithosphere deformation monitoring of our country is studied. The rigid block movement model under the ITRF93 frame is established by using 92Ⅲ and 96Ⅱ adjustment precept, which have the same reference frame and mutual initial epoch; and it is compared with the NNR-NUVEL1A mdoel. At the same time, the model of the movement between rigid blocks is studied. The result is in correspondence with geological result.
The image registration is one of the key points in the integrative analysis of image data. In this paper, a full-automatic method for the registration of remote sensing imagery with different resolutions and/or from different sensors is described. The results applied to SPOT and TM imagery show that the method is much better than the traditional manual approach both in efficiency and accuracy.
This paper discusses the methodology to process single epoch GPS observations for deformation surveys. It takes full advantage of the characteristics of deformation surveys, i.e., the position of a surveyed point changes relatively small between two consecutive survey epochs. Special attention is given to efficient solution of carrier ambiguities and multipath effects. The tests indicate the methodology works well and an accuracy of a few millimeters is achievable. The developed method can be used to process the GPS data from both slow deformation and rapid/dynamic deformation monitoring.
Because of the difficulty in description of geo-features with a single value of fractal dimension,it is necessary to perform extension from the original constant dimension value which is independent upon measure step lengths to variable one which can be considered as a function depended upon measure step lengths. In this paper the author proposed principles and methods to establish the inverse S shaped curve function and to examine the suitability of this model for enhancing the ability to describe complexed phenomena.
This paper discusses the basic principles of genetic algorithms and its detail algorithms in image texture classification. The results of the experiments of four texture samples show that the method of image texture classification based on genetic algorithms can improve the correct probability of classification.
A new type of airborne laser image mapping system (ALIMS) and its principle, technical structure, data processing and development are presented in this paper. The ranging principle used in ALIMS is a breakthrough in remote sensing technical system. ALIMS's main features are high efficiency, the ability to position and attribute simultaneously, so it can become a new effective remote sensing technical system to monitor resource and environment hi-dynamically.
It has been analyzed that there are a lot of advantages for engineering surveying using a system based on laser-theodolite with three freedoms of rotation. Some solutions for corresponding scanning relations are presented in detail. Using the system an important application was successfully completed.
Special designed patterns, e.g. several parallel lines with black and white tones, are used for automatic location and orientation of a three dimensional movable object in the room environment, in which the special designed patterns are painted on the walls of the room. Three CCD cameras or at least one mounted on the object are used to take the images from the wall patterns, which are transferred to the computer via radio. The features of such patterns can be extracted full automatically. Then the shifting parameters (HX, HY, HZ) and the rotation parameters (h,k,κ) can be automatically calculated without any manual operation. The algorithm is based on traditional photogrammetrical theory. But special new formulas are derived for the designed patterns, and some simplifying processing are proposed.
Reconstruction of 3D landscape for urban region is an important research in digital photogrammetry and visualization. By means of object extracting technique, corners of the house have been located automatically according to approximate points firstly in this paper. Then, the window, including much area of house proof instead of centering at the corner of house, is created to perform image matching for house corner. The reliability of image matching is improved. After the 3D data of houses are measured semi-automatically, texture restoration of visual surface on the buildings is achieved based on the 2.5D triangulated irregular network of ground and building surface and original digital image. The real 3D landscape of urban is reconstructed.
Formal description and representation of topological relationships between 3D spatial features is one of the key issues in developing 3D GIS. An approach was proposed in this paper to describe the topological relationships between 3D spatial features with their k-simplex components (0≤k≤3). The topological relationships for the pair of k-simplex were examined with dimension extend 9-intersection. Six types of primitive relations were used, such as touch, cross, in, disjoint, overlap and equal. The topological relationships between 3D spatial features were described with a topological matrix T which compared the relationships between any two k-simplex of the two 3D spatial features.
The development of Internet provides convenient environment for information indexing and browsing. It also offers a new platform for geographic information processing and analysis. This paper discusses organization and processing approach to Internet geographic information, and provides a new method to cross-platform and distributed geographic information and its software implementation. The example is used to show the practicality and superiority of this method.
This paper discusses the principles and methods of fractal assessment in image texture analysis, gives out the concept and practical approach of multiband image texture analysis, and introduces the experiment results of texture analysis using fractal assessment for single band and multiband images in terms of the principles discussed in this paper.
An elementary query model is a key factor to implement spatial information query in GIS. A common query model in database is outlined in this paper and a powerset query mode is put forward based on construction of set. In regard to data models, a query capacity is defined for assessment of query models. The powerset-based query model is examined according to the capacity.
This article addresses the photogrammetric theory in stereo vision, particular with non-metric camera. The discussion is embedded in projective geometry, which can be regarded as an extension to conventional photogrammetry with metric camera in Euclidean geometry. The cross-ratio of volume elements is shown as projective invariant after the spatial projective transformation is properly introduced. The volume cross-ratio is thus defined as projective independent measure for object description. The fundamental matrix in stereo vision is decomposed into a production of two matrices, projective base matrix and projective-rotation matrix, as defined in the article. This concept inherits the one of the essential matrix for metric camera, and leads a concise soultion to projective coordinates and homogeneous corrdinates of the projective model. In order to reconstruct the object from its projective model, a three dimensional direct linear transformation (3-D DLT) is proposed, with which the object reconstruction can be performed linearly with minimum five conjugate known object points. Tests results and analyses verify the theory and methodology.
This paper deals with automatic reconstruction of a digital multi-ray photogrammetric network, which comprises multiple nodes, each node indicating one object point and its corresponding multiple-imaging rays. In the automatic reconstruction, a novel multi image matching (MIM) technique without similarity measurement is proposed. The technique includes consecutive consideration of all images as reference images. In the proposed strategy, matching accuracy is enhanced by sub-pixel interest point extraction and multi-ray traingulation.
Spatial information is another form of information in contrast with text information represented with natural language. The interior structure, representation and understanding mechanism are the prerequisites to realize the capturing, managing and processing of spatial information. As many years passed, GIS has succeeded as a technology of engineering, especially in the field of data management and non-intelligent data processing. However, it is generally accepted that the further progress of GIS depends on the more concern with the spatial information itself. In this paper, based on the drawback analysis of traditional GIS theory, linguistics is introduced into GIS. The understanding paradigm of the structure and representation of spatial information in digital context, i.e. linguistic paradigm of spatial information is proposed. The linguistic characteristics of spatial data in terms of language unit, syntax and semantics are discussed, along with the influence on the aspects of GIS with special care about the intelligent data processing.
This paper selects a set of actual aerial photographs with the camera position determined by GPS kinematic positioning, and analyzes the theoretical accuracy of GPS-supported bundle adjustment by calculating the accuracy matrix Qxx. The block range and the arrangement of ground control points for GPS-supported bundle adjustment were given based on the above experimental results. In addition, the GPS application feasibility and method on GPS-supported adjustment by single strip were discussed.