This PDF file contains the front matter associated with SPIE Proceedings Volume 6751, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Multi-resolution representation plays leading roles in virtual geographic environment (VGE), interactive simulation and visualization, fly simulation etc. This paper presents an efficient implementation of adaptive view-dependent and topology preserving algorithm with which progressive meshes can be selectively refined or coarsened. In contrast to view-independent algorithms, it allows several different levels of detail to co-exist across different regions of the same object. Regions with great visual importance are represented with high resolution, other parts are represented with lower resolution, and so sizes of LOD models generated with the algorithm presented in this paper are much smaller. In the real-time generation of view-dependent LOD models and its update, parameters such as view point, view frustum, normal of vertices, and position of vertices are all considered. The algorithm mainly consists of two phases: pre-processing and real-time update. In the preprocessing phase, an algorithm based on quadric error metric and edge collapse operator is employed to simplify the original model, and so the original high resolution model can be represented with a coarse base model and a sequence of edge collapse records, which we also call progressive mesh representation. In the real-time update phase, progressive meshes are selectively refined or coarsened according to their visual importance. It is believed that regions fulfill the following two conditions simultaneously are of great importance: (1) intersection of normal cones and view frustum are non-empty; (2) the affecting area of a certain candidate vertex joins current view frustum, and so they will be represented with a high resolution, otherwise, they will be represented with a relative lower resolution. In contrast, the following two characteristics are different from others: (1) Binary trees are stored implicitly in the edge collapse records, so spending on memories is less, most important of all, depth of binary trees constructed in this paper is at least one less than previous algorithms, therefore, traversing of them is faster. (2) Due to the special edge collapse operator employed in the pre-processing phase, precondition for vertex split operations are more relaxed, and so it is easy to get simplified models with fewer amounts of data under the condition of same visual effects.

Different geographical phenomena and processes take on diverse laws, this is to say, specific laws of geographical phenomena and processes should be researched on a given spatial scale. In addition, geographical phenomena and processes don't linearly change with spatial scale, which can't obtain by linear interpolation or extrapolation. As a result, we must resolve the problem of multi-scale representation of geographical spatial data, which is also the key technique of Multi-Scale GIS or Scale-Free GIS. At the present time people have to adopt multi-ply representation for the sake of satisfying people's research and production needs on different spatial scales. However, this method has such shortcomings as a good many data redundancies, ensuring no the consistency of the same spatial entity on different spatial scales, low efficiency of updating spatial database and bad real-time characteristic of spatial database. Ideal aim of multi-scale representation of geographical spatial data is deriving desired spatial database of various scales or detail degrees from dominant cartographic database, which is automatic generalization of geographical spatial data. Research fields of automatic generalization of geographical spatial data include theory foundation, concept framework, solution and algorithms of automatic generalization. Therein algorithms of automatic generalization are the technique basis of automatic generalization of geographical spatial data. Since the seventies of the last century people have already put continuously forward a large number of algorithms of automatic generalization. Those algorithms have indeed resolved a good many important problems, but they have some obvious shortcomings and application confines. This article makes a research on those algorithms of automatic generalization, and research contents comprise classification, principle, application confines, merits and drawbacks of algorithms of automatic generalization. This paper also brings forward the research orientation of algorithms of automatic generalization for the future.

There are so many emergency issues in our daily life. Such as typhoons, tsunamis, earthquake, fires, floods, epidemics, etc. These emergencies made people lose their lives and their belongings. Every day, every hour, even every minute people probably face the emergency, so how to handle it and how to decrease its hurt are the matters people care most. If we can map it exactly before or after the emergencies; it will be helpful to the emergency researchers and people who live in the emergency place. So , through the emergency map, before emergency is occurring we can predict the situation, such as when and where the emergency will be happen; where people can refuge, etc. After disaster, we can also easily assess the lost, discuss the cause and make the lost less. The primary effect of mapping is offering information to the people who care about the emergency and the researcher who want to study it. Mapping allows the viewers to get a spatial sense of hazard. It can also provide the clues to study the relationship of the phenomenon in emergency. Color, as the basic element of the map, it can simplify and clarify the phenomenon. Color can also affects the general perceptibility of the map, and elicits subjective reactions to the map. It is to say, structure, readability, and the reader's psychological reactions can be affected by the use of color.

Grid-city management currently attracts a wider audience globally. Socio-economic data is an essential part of grid-city management system. Social-economic data of an urban is characterized by discrete, time-varying, statistical, distributed and complicated. Most of data are with no exactly spatial location or from various statistical units. There is obvious gap while matching social-economic data with existing grid map of natural geographical elements emerges. It may cause many difficulties in data input, organization, processing and analysis while the grid system constructing and executing. The issue of how to allocate and integrate the huge social-economic data into each grid effectively is crucial for grid-city construction. In this paper, we discussed the characteristics of social-economic data in a grid-city systematically, thereafter a cell-based model for social-economic data representing and analyzing is presented in this paper. The kernel issues of the cell-based model establishment include cell size determining, cell capabilities developing for multi-dimension representation and evaluation, and cell dynamic simulation functions designing. The cell-based model supplements the methods system of spatial data mining, and is also promising in application to the spatialization of statistical data obtained from other researches including environmental monitoring, hydrological and meteorological observation.

The history of editing National Atlases in the world was summarized at first, and follows with China's achievements in editing of the 1st and 2nd version of The National Atlases of China (NAC), which reflected, in multiple levels, China's development of science and technology, society and economy, resources and environment, etc. from 1950s to 1980s. From the previous edition of NAC, systematic theories and methods were summarized and concluded, including comprehensive and statistical mapping theory, designing principle of electronic atlases, and new method the technologies involved in NAC. Then, the New Century Edition of NAC is designed, including its orientation, technological system, volume arrangement, and key scientific and technological problems to be resolved.

3D Laser scanning technology plays an important role in buildings model reconstruction, mechanical modeling, heritage conservation, tunnels modeling, bridges and mine monitoring, etc. This technology can acquire accurate and dense 3D points cloud data in a short time, and it's becoming an important data acquisition means of 3D model. The construction of high-quality 3D triangulated irregular network (TIN) using the irregular points cloud is one of the key problems in model reconstruction. However, the 3D triangulation of discrete points cloud is a difficult problem and contains very complex principle, until now, the problem has not been satisfied resolved. In this paper, a 3D Delaunay triangulations algorithm of terrestrial laser scanning data based on spherical project is proposed. In the algorithm, the connection characteristics of the 3D laser scanning data are deeply investigated and utilized to help judge the relation of irregular points.

This paper explores an approach for predicting land cover types of central Montana, USA based on satellite measurement and digital terrain data. We assume a non-linear inherent relationship existing between land cover types and Landsat TM reflectance and terrain variables. To measure this relationship we use Generalize Linear Models (GLMs), which are mathematical extensions of ordinary least-square regression models. Specifically, stepwise logistic regression technique is applied to optimize the predictive model. For the analysis of the significance of dropping or adding terms, the Akaike information criterion (AIC) is used. Likelihood Ratio Test (LRT) is applied to test the validity of explanative potential of predictor variables. We use cross-validation method to evaluate the predicative accuracy of land cover mapping using GLMs. Finally we table the relative risk ratios of GLMs. Since relative risk ratios explicitly represent the explanative efficiency of predictor variables, their ranking can pick up the variables with significant explanatory potential in discriminating land cover types, which will be significative for simplifying the predictive models. It is anticipated that GLMs will be valuable extension to semi-automatic classification of remotely sensed imagery, and an effective tool for land cover mapping.

It is a delicate task to design suitable geovisualisations that allow users an efficient visual processing of geographic information. In digital era, such a design task is confronted with a three-fold challenge: the ever growing amount of geospatial data at various granularity levels, the diversified applications and the continuously expanding range of display sizes. A geovisualisation system that strives for a high usability must satisfy the crucial prerequisite of immediately directing the user's gaze to the location of relevant geographic information and of easy decidability of the underlying semantic meanings. To this end, the cognitive skill of visual attention contributes to mnemonic and executive processes. Attention is indispensable for the visual selection. It facilitates the relevant information retrieval, processing and storage. On the basis of neurocognitive visual information processing, the paper addresses the interdisciplinary approach of attention-guiding design of geovisualisations with the intention to establish a taxonomy of scientifically testable variables. The authors try to relate attention-guiding attributes with graphical variables that cartographers apply to encode geographic information. The work is driven by the motivation to enhance the efficiency of geovisualisations and to enable a more precise neurocognition-based evaluation of geovisualisations.

In contrast to traditional cartography, schematic network map including road and river network needs new cartographical generalization methods. In this paper, the cartographic design criteria of schematic road network map are analyzed and summarized. Based on this, a set of quantitive constrains are set up, and a new road network generalization method including progressive selection and displacement is proposed. Furthermore, we research topological checking method for road network. Based on these constrains, the points in a road network are classified, and a satisfied and effective schematic map is designed in a concrete experiment, while keeping the topological consistency of the road network between original and schematic map.

Delaunay triangulation is always used to construct TIN, and is also widely applied in manifold fields, for it can avoid long and skinny triangles resulting in a nice looking map. A wide variety of algorithms have been proposed to construct delaunay triangulation, such as divide-and-conquer, incremental insertion, trangulation growth, and so on. The compound algorithm is also researched to construct delaunay triangulation, and prevalently it is mainly based on divide-and-conquer and incremental insertion algorithms. This paper simply reviews and assesses sweepline and divide-and-conquer algorithms, based on which a new compound algorithm is provided after studying the sweepline algorithm seriously. To start with, this new compound algorithm divides a set of points into several grid tiles with different dividing methods by divide-and-conquer algorithm, and then constructs subnet in each grid tile by sweepline algorithm. Finally these subnets are recursively merged into a whole delaunay triangulation with a simplified efficient LOP algorithm. Because topological structure is important to temporal and spatial efficiency of this algorithm, we only store data about vertex and triangle, thus edge is impliedly expressed by two adjacent triangles. In order to fit two subnets merging better, we optimize some data structure of sweepline algorithm. For instance, frontline and baseline of triangulation are integrated into one line, and four pointers point to where maximum and minimum of x axis and y axis are in this outline. The test shows that this new compound algorithm has better efficiency, stability and robustness than divide-and-conquer and sweepline algorithms. Especially if we find the right dividing method reply to different circumstance,its superiority is remarkable.

Object selection is an important technical problem in the process of map generalization. Considering creative-thinking characteristic of map generalization process, the paper bring the Rough Set theory from spatial data mine field to map generalization field, put forward a new thought for map generalization based on classification idea of Rough Set. The method of Rough Set which has the benefit on enormous data with the imperfection and non-precision character has become a new tool to make research on spatial data mining. The paper analyzes the imperfection characters of geo-spatial data processing based on Rough Set and the selection problem in the processing of map generalization with classification thought; presents the thought that map generalization is a kind of classification for map objects. The method mentioned in this paper use different spatial and attribute information as different point of view to observe the map objects. The result of the classification is ordered by the weightiness of all kinds of factors. In the end, a river objects selection test validates the rough set map generalization method mentioned in this paper.

In order to reveal and implement the corresponding association about the same geographical feature at different resolutions and to build the multi-scale spatial database and maintain the consistency between different scale map databases, an algorithm for matching multi-scale linear objects based on Hausdorff Distance as a matching measure is proposed combined with the semantic information. Further more, the concept of matching uncertainty is defined as to evaluate the matching result. The experiment and the estimate result show that according to the characteristics of road networks changing with scales, this approach can recognize the entity or a set of entities which represent the same object at different scales so as to build the relationships of corresponding objects.

This paper proposes a progressive approach to selecting streets from an urban street network. This approach relies on the constraints in generalization of the street network and the ameliorated dynamic decision tree structure which represents the map data by a tree. The paper begins with a review of theory and methodology of constraint-based map generalization, of approaches to generalization of the road network and street network, and of some auxiliary structures which are useful to represent contextual topological relation. And then a conceptual framework for map generalization is presented. In the following, the methodology is described under this framework and the ameliorated dynamic decision tree structure is introduced in detail. An algorithm is developed and the proposed approach is validated by a case study. The paper concludes with some discussion on the benefits and shortcomings of the approach.

This paper mainly discusses how to realize the symbolization control of digital maps through symbolization control knowledge. First, the author briefly introduces basic concepts and means of realizing symbolization control of digital maps after analyzing the current problems of digital map symbolization. Then the author analyzes the composition of the symbolization control knowledge, and proposes some important concepts such as the expression of geographic attributes, the annotation's positional control code and the format string expression. Finally, the author designs and realizes the symbolization control interface with man-machine interaction. Practice has also proved that it is effective to realize the symbolization control of digital maps through knowledge of symbolization control.

Drainage generalization is a process of information abstraction, aiming to derive a coarser dataset from original detailed one. The difficulties lie in selectively omitting some rivers while maintaining the overall characteristics of the drainages. This paper took use of the amount of the tributaries of individual rivers to evaluation their relative importance in the drainage, and the contribution to the preservation of the drainage pattern. That is, the rivers having more tributaries are more important than those having fewer tributaries; at the same time, the differences of the amount of the tributaries of the rivers may indicate the density differences of their sub-drainages. In view of the important role of river length and hierarchical level in manual generalization, we combined river length, hierarchical level and the amount of the tributaries to evaluate rivers. The three indexes were computed, and then integrated as a complex index for every river, on the basis of constructing a river tree of the drainage. A case study of drainage generalization shows that the complex index is effective to reflect the relative importance of the rivers in the drainage, and can be used to maintain the density differences of the drainage in map generalization.

The acreage of a land parcel is the area of the parcel's coverage on the geodetic ellipsoid surface. There are two methods to compute the land parcel acreage from its area in the map projection coordinate system. The first method is to compute the acreage of an administrative zone, then use the acreage of the administrative zone to control the acreages of the land parcels within it. The second is to compute the acreage of a map sheet first, and then use the acreage of the map sheet to control the acreages of the parcels within that map sheet. There are three methods to calculate the slope grade of land parcels, each has advantages and disadvantages. They should be used under careful consideration of the specific situation.

This paper studies the principle, method and application of spatial points clustering based on self-organizing neural networks. In this paper, we put forward a kind of composite clustering statistic, called generalized Euclidean distance, which is calculated by both geometric and semantic characters of spatial points. We propose the algorithm of spatial points clustering based on self-organizing feature map and generalized Euclidean distance. The clustering method in this paper can generate better result reflecting the clustering characters of spatial points. Finally, we employ a case study to probe into data classifying, gross error detecting and homogeneous areas partitioning using self-organizing spatial clustering result.

Urban Underground Pipeline System has grown up to diversity and complex networks; moreover, they have the characteristics such as invisibility, magnanimity and continuous variation. It is necessary for accelerating development of city to establish integrative model of urban pipeline-road-stratum with the techniques of Digital Underground Space and Engineering (DUSE). The key method of some spatial analysis are presented in the present model, it includes integrative break surface analysis, horizontal net distance analysis and cross vertical net distance analysis in any of the given section; especially, DUSE takes out the three dimensional distance analysis or interference judgment between pipelines. Nowadays, the general method which distinguishes the state of interference in multi-manipulator system simplifies shaft into line-segments, then calculates the distance between two line-segments or the intersected position without taking the shape of shaft into consideration. In DUSE, the state of interference in pipelines is computed by Boolean operation; if two pipelines haven't intersection, a series of algorithms based on the theory of analytic geometry is put forward to calculate 3D distance between circular pipelines, quadrate pipelines or their combination.

Earlier research has introduced the concept of discriminant space, which is spanned by the covariates underlying area-class occurrences, for increased consistency, interpretability, and replicability in area-class mapping and uncertainty characterization. While simple univariate cases with b=1 (b being the dimension of the discriminant space) were investigated previously using simulated data, real world applications are usually multivariate with b>1, thus giving rises to the need for developing discriminant models in spaces of higher dimensionality for increased applicability. This paper describes combined use of generalized linear modeling and kriging for area-class mapping, with the former deterministically predicting mean class responses while the latter making use of spatially correlated residuals in the predictive class models. Scalability in area-class mapping is facilitated by flexible implementation of scale-dependent prediction of mean class responses and point- vs. area-support kriging of the residuals. This is followed by an empirical study concerning land cover mapping in central western Montana, which confirmed the effectiveness of the proposed strategy combining regression and kriging for scale-dependent mapping of area classes.

A new classification scheme of elevation points is put forth on the basis of the study about different kinds of elevation sampling points and feature lines used to build Digital Elevation Model (DEM). All the elevation points are divided into two classes, namely Control Elevation Point (CEP) and General Elevation Point (GEP). GEP is subdivided into two subclasses, namely, Key Elevation Point (KEP) and Dense Elevation Point (DEP). In order to depict micro-terrain with fine resolution and high efficiency, especially the micro-terrain in plain, six kinds of elevation points are used to construct Delaunay Triangulated Irregular Network (D-TIN) successfully in case study. It shows that these elevation points can be used to represent the complex micro-terrain like isolated hills with fine resolution and high efficiency by use of traditional D-TIN constructing algorithm and 3D terrain visual algorithm if they are sampled along their corresponding feature lines and Dense Elevation Points (DEPs) are far enough from any feature lines. The representing resolution changes along with the number of DEPs. The case study also shows that a new elevation points sampling strategy is required to ensure the correction of D-TIN and a new visual algorithm to visualize the cliff surface more smoothly.

There is some relationship between the Digital Surface Model (DSM) and the Digital Terrain Model (DTM). The contents they express are relative: DSM expresses the height we focus on about the surface of the ground, including the terrain and the objects on it, and DTM only gives the height of the terrain excluding the objects above it. DSM have the information of DTM, therefore it provides us a chance to subtract the DTM from the DSM. Mathematical morphology is a new method applied to Imagery processing and pattern recognition fields. It provides an effective method of subtracting DTM from DSM. But in practical application, the original calculations of these two are in low efficiency. Especially when it comes to a large template or huge block data, the computation speed can be a very headache question. This paper is studying the implementing process of the Open and the Close operators, especially the Erode and the Dilate calculations. Then we have developed two kinds of quick algorithms, which are aim to avoid the repeated calculation, and to enhance the efficiency sharply. The step of the two operations also should be refined, while the disposals are different from each other depending on the distinct configuration of these two kinds of algorithms.

Digital cartography provides lots of geographic data for our society, although the traditional technology of cartography is very complex and tortuous. Also its long produce-cycle affects the effort of maps. Based on introduction of Model-Driven theory, this article shows a construction of automated framework of task-flow, and gives the methods for building the key components. At last, an example of data exchanging is provided to validate the feasibility of automated framework theory.

For monitoring or tracking a vehicle locally or remotely, positioning information should be stored locally or transferred through wireless network timely. One of those key problems in such a system is to find an appropriate time-duration to update the position of the vehicle. If the time-duration is too small, too much positioning data will be stored locally or be transferred; but if the time duration is too big, the track cannot be recorded faithfully, and you can not identify the actual route the vehicle just went through. To resolve this problem, an adaptive method based on map-matching technology and fuzzy description is presented in this paper. Through running map-matching by comparing the vehicle's positioning information with road network geometrical and topological information in digital maps, a more precise position can be obtained and the current road can be identified. After that, the following factors are considered to detect whether the current position need be updated in center control unit: time duration, running distance, estimation error, the vehicle state changing, and running road changing. A deduction method is used to estimate and compare with the measured vehicle state. And a quantitative fuzzy description is used to describe the speed and angular speed of the vehicle. After that, an OR arithmetic logic computing unit is used to decide whether need update current position to center control unit. Finally, a test is given to evaluate this algorithm. The proposed adaptive algorithm can record the vehicle's track faithfully, and at the same time it decreases the communication cost between the mobile station and the center control unit.

Cartographic visualization represents geographic information with a map form, which enables us retrieve useful geospatial information. In digital environment, cartographic symbol library is the base of cartographic visualization and is an essential component of Geographic Information System as well. Existing cartographic symbol libraries have two flaws. One is the display quality and the other one is relations adjusting. Statistic data presented in this paper indicate that the aliasing problem is a major factor on the symbol display quality on graphic display devices. So, effective graphic anti-aliasing methods based on a new anti-aliasing algorithm are presented and encapsulated in an anti-aliasing graphic library with the form of Component Object Model. Furthermore, cartographic visualization should represent feature relation in the way of correctly adjusting symbol relations besides displaying an individual feature. But current cartographic symbol libraries don't have this capability. This paper creates a cartographic symbol design model to implement symbol relations adjusting. Consequently the cartographic symbol library based on this design model can provide cartographic visualization with relations adjusting capability. The anti-aliasing graphic library and the cartographic symbol library are sampled and the results prove that the two libraries both have better efficiency and effect.

The Regional Geological Mapping (RGMAP) System developed by China Geological Survey Bureau is a GIS system for digital geological mapping, which has made a great change to traditional geological survey. RGMAP is composed of two parts: Digital Route System and Digital Section System. Each of them contains two subsystems, namely, the Palm-PC-Based Field Data Capture System and the In-house Desktop System. We discuss mainly the Digital Section System in this paper. In the field, we have achieved the section measuring digitally in computer by means of using the Palm-PC-Based Field Data Capture System. The Digital Section System (In-house Desktop Subsystem) can automatically calculate the thickness bed by bed, as well as create the Measured Section Chart and Columnar Chart, which has dramatically enhanced the measurement of geological section and its cartographical techniques.

Normally, agricultural land parcels being close to town centers and connected with road systems have higher probability to be converted for newly planned settlements because these land parcels have higher accessibility influenced mainly by the transportation condition. A comprehensive method is proposed to simulate the process of allocating land parcels for the newly planned settlements with the raster data model using some elementary spatial analysis functions provided by ArcGIS. The first step of the method is to construct the distribution of the cost-distance from each transferable land parcel to the centers of administrative units at village level (called 'origin' for short). The second step is to simulate the process to allocate the transferable land parcels for satisfying the land demand resulting from the development at these 'origins'. It is quite possible that more than one origin is interested in the same transferable land parcel. Therefore, how to determine the priority of different origins to get the land parcel focused by more than one origin is emphatically discussed as one key point of the proposed method in this paper. In addition, some other aspects, such as the size of the transferable land parcels, which influences strongly on the results of assignment, are discussed as well. The proposed method has been applied in the Sino-Germany project 'Sustainable Development by Integrated Land Use Planning' and can meet the requirements.

The mutual conversion between analog map and digital map is two main contents of the study on digital mapping, which is the production of paper map and spatial data. The visualization of spatial data is the common problem that the spatial data application system confronted, so it is practically meaningful to study the mutual conversion between analog map and digital map. The paper indicates the two processes of the decrease and increase of cartographic information content in two conversions, educes a cartographic information transfer model based on Shannon communication system model, and makes a deep quantitative and qualitative analysis on the decrease and increase of cartographic information in analog/digital conversion in terms of information theory and cartographic theory. The paper also shows that the accuracy of cartographic information should be improved in analog-digital conversion and the information content transformed should be increased to the fullest extent in digital-analog conversion. The corresponding disposal is respectively given for the two processes.

Although the production of nautical chart has developed a lot in China, there are still some defects, such as the long period of producing nautical chart, the continuous correction to the nautical chart published, and so on. On basis of analyzing Chinese chart publishing data and its updating data, this paper researches on the technique of interactively updating server chart publishing data and the technique of automatically updating client chart publishing data, which will lay the foundation for constructing the mode of printing charts on demand in China.

Web online applications present a lot of challenges for spatial data generalization, in this paper, a novel method of spatial data generalization for real time visualization is presented. In this method Quadtree Index of Priority (QIP) is used to control real time data generalization in 3D rendering process. Priorities of points elimination from objects is composed of contrived priority and automatic priority. Contrived priority is determined by attributes of objects, while automatic priority is automatically calculated from object's geometry shape by vision-based algorithm and Fast Segmentation (FS) algorithm. In addition, quadtree index of priorities is also proposed to be used in global data generalization control. In order to test the generalization method, an experiment with large scale vector data visualization is given.

According to studying the coastline, a new way of multiple representations is put forward in the paper. That is stimulating human thinking way when they generalized, building the appropriate math model and describing the coastline with graphics, extracting all kinds of the coastline shape information. The coastline automatic generalization will be finished based on the knowledge rules and arithmetic operators. Showing the information of coastline shape by building the curve Douglas binary tree, it can reveal the shape character of coastline not only microcosmically but also macroscopically. Extracting the information of coastline concludes the local characteristic point and its orientation, the curve structure and the topology trait. The curve structure can be divided the single curve and the curve cluster. By confirming the knowledge rules of the coastline generalization, the generalized scale and its shape parameter, the coastline automatic generalization model is established finally. The method of the multiple scale representation of coastline in this paper has some strong points. It is human's thinking mode and can keep the nature character of the curve prototype. The binary tree structure can control the coastline comparability, avoid the self-intersect phenomenon and hold the unanimous topology relationship.

The research introduces skeleton extraction algorithms into cartographic generalization to solve the problem of cartographic generalization of cultivated land polygons in hilly areas. The study selects southwest region of the Ningxiang County in the Changsha City as the research area and national land use survey on the scale of 1: 10000 as data source, chooses an appropriate skeleton extraction algorithm depending on the research purpose and data source, and propose an improved algorithm applicable for cultivated land in hilly area after a lot of experiments. And then the improved algorithm is applied to cartographic generalization work of cultivated land in the research area. Results show that: first, the improved skeleton extraction algorithm is simple, easy and efficient; secondly, under the condition that scale changes greatly, it could still retain the Figacteristics of cultivated land polygons' distribution and shape and satisfy the requirements of cartographic generalization and human vision.

The Meta Fractal Dimension (abbreviated as MFD) Model is a method which extends the fractal research of map objects. During the establishment of MFD, the size of sliding window determines the neighborhood range which restricts the segment from the map object and the degree of adjacent overlapped, thus it is one of the most important parameters for MFD. In present research, however, it is chosen artificially, that causes random and unsatisfied operating efficiency. Considering the extended fractal character with scaling variance, and based on its simulating function adopting the Inverse Logistic Model, the paper proposed a method to determine the size of sliding window automatically for constructing MFD of map curve, viz. MFD curve. Several experiments done indicate that this method is easy to operate and has a relatively high calculation precision and a logical result of spatial analysis.

Since decades it has been a dream of cartographers to computationally mimic the generalization processes in human brains for the derivation of various small-scale target maps or databases from a large-scale source map or database. This paper addresses in a systematic way the polarization transformation (PT) - a new algorithm that serves both the purpose of automatic generalization of discrete features and the quality assurance. By means of PT, two dimensional point clusters or line networks in the Cartesian system can be transformed into a polar coordinate system, which then can be unfolded as a single spectrum line r = f(α), where r and a stand for the polar radius and the polar angle respectively. After the transformation, the original features will correspond to nodes on the spectrum line delimited between 0° and 360° along the horizontal axis, and between the minimum and maximum polar radius along the vertical axis. Since PT is a lossless transformation, it allows a straighforward analysis and comparison of the original and generalized distributions, thus automatic generalization and quality assurance can be down in this way. Examples illustrate that PT algorithm meets with the requirement of generalization of discrete spatial features and is more scientific.

It is difficult to carry out the automatic cartographic generalization of urban buildings, because of their complex shape. An algorithm and some constraints for generalization using Least Squares Adjustment theory are presented, with analyzing the procedure of generalization for urban buildings under multi-scale environment. Automatic generalization for building polygons can be carried out in the algebra way, with building the automatic generalization adjustment model including simplification, aggregation, displacement and symbolization. The practice shows that the object shape is represented perfectly by the algorithm, with providing a basis for evaluation on results of generalization, which improves the procedure of automatic generalization in scientific and feasibility.

In this paper, the feature selection rules of patches were regarded as the breakthrough point, based on data analysis and experiments, the computing method of area balance control of land types was put forward in order to solve the problem of area changes of every land type before and after synthesis. The computing method of area balance control of land types can be used not only to check up the rationality of rules before cartographic generalization, but also to provide assistance advice for revising feature selection rules according to the requirement of the synthesized results. It is helpful to enhance the rationality and reliability of synthetic rules, to achieve the area balance of various land types before and after it is synthesized, and to guarantee the quality of the diagram.

Map objects' displacement is an important operator in the map generalization and spatial information visualization. In this paper, the constraints of map objects displacement and their satisfaction method with the finite element method are discussed, in which the constraints of map objects displacement and strategies of parameters of finite element method in the displacement process play important roles for the displacement result, and compromised with the spatial reasoning method, a progressive node displacement method is discussed in this paper, which is examined with a road widening case. And the result shows that the force and the force propagation can be considered comprehensively in this method, through which unnecessary map object displacement can be avoided.

In the paper, the main method we discuss and improve relates to the snake model, which is used to displace the roads and resolve the conflict. A snake is an energy-minimizing spline guided by internal constraint forces and influenced by external enforcement. In the paper, the theory of snake model is illustrated in detail. Then, according to the demand of cartography, the snake model is improved as follows. First, the relationship between the parameters of snake and shape character of road is built up in order to keep the shape of displaced road better. Second, the propagation extent of external force in snake model is controlled to keep the accuracy of road position. Third, the power attribute of intersection point between roads is set to control the displacement of the intersection point and keep the topological relationship of roads. At last, the general thought of disposing the spatial conflict of road networks are brought forward by using the improved snake model. One experiment research is made in terms of the general thought, which represents that the roads are displaced and the spatial conflicts are solved well.

This paper presents a new method of extracting and identifying point-shaped symbols of scanned topographic maps based on Distance Transformation. First, we remove of the interferences of transition color pixels on symbol edge, and filter the lines which do not meet the features of point symbols according to curve density and line density, and extract point symbols from the map based on adding hull transformation and removing skin transformation. Then we judge topology consistency by skeleton of symbol and shape consistency by weighted distance function, and use the both consistency to identify symbols. The algorithm can extract and identify rotated or distortional point symbols in the condition of character and line conglutination or complex background, and the identification accuracy is 98%.

In the practice of cartography, people always face two kinds of geographic world's models. One is digital landscape model (DLM), and another is digital cartographic model (DCM). In DLM, geographic feature are expressed by coordinate, attribute and relationship among them, it is independent from symbols. Reversely, DCM is closely related with symbols and paper maps which will be published. In this paper I will discuss the design of map database for DCM. First, this paper introduces characteristics of GIS database and Map database to us, and then elaborates their relationships and differences. Second, it represents the contents of map database, which consists of five parts such as spatial location, attributes, spatial relationship, time, symbol and cartographic expert's knowledge for symbolization control. So we can draw a conclusion that the map database is an organic combination of GIS database and cartographic expert's knowledge. Third, this dissertation depicts the implement of map database by an example which is applied in the paper topography mapmaking and infrastructural geographic information's yield. We design data tables according to geographic feature's geometry type such as point, line, polygon, complex and annotation. By foreign keys related to dictionary tables we can divide features into different geography layers (such as vegetation, river, road etc.) and publish layers (such as red point, black line, green polygon, black annotation etc.). Aiming at different geographic feature possessing of different items of attributes, we also design a universal method to store feature's attribute data. Fourth, this dissertation introduces a method using cartographic expert knowledge and experience to control the process of dynamic map symbolization. The authors think it should formalize the fuzzy and ambiguous expert knowledge and build expert knowledge repository. By an example it illustrates how to establish cartographic expert knowledge repository and how the formalized expert knowledge to control the geographic features' symbolization. And then, it elaborates how the formalized cartographic expert knowledge to controls the annotations' symbolization on a map.

Map projections are attempts to portray the surface of the earth or a portion of the earth onto a flat map surface. This can not be done without any distortions of conformality, distance, direction, scale, and area. There are many map projections, and each of them has its own set of advantages and disadvantages. The mapmaker must select the one best suited to their application needs, reducing distortion of the most important features. However, how to select a 'proper' map projection is a complex process involving general evaluation of map projection alternatives based on a set of characteristics that describe these projections. And this process needs a systemic understanding of map projection, which usually can not be achieved by end users. This paper introduced Expert system (ES) to solve this problem, and used Component Objects Model (COM) technology to develop and interoperate the proposed system (developed with Visual Prolog 7.0 Personal Edition®) with professional Geographical Information System (GIS) software. As an essential part of the article, the authors also represented the knowledge, rules and reasoning methods of selecting an appropriate map projection as well. Implementations and examples had been given to testify the feasibility.

Geographic Information Systems, especially accurate digital traffic maps, have been becoming widely used in the Intelligent Transportation Systems. The GPS data usually are more accurate than the pre-existing base map data. This paper introduces a new cartography procedure for making digital map from a start-up paper map, which has no geography data (longitude and latitude). Contrary to traditional map-making which is first a precise survey-cartography and follow-on digital controlled mapping, the new procedure is first extracting layer from a raster map and vectorization, follow-on geo-adjusting for pinpointing all nodes on the vector map. There are two key processes in the new digital map-making technique. First, the map layer extraction is controlled by output feedback for optimal recognition of road network. Second, a dynamic topological mapping is developed for geo-location and improving the accuracy of vector traffic map by utilizing some recorded GPS data as the controlled pinpoint samples. Different from those traditional geolocation methods such as affine mapping, and the rubber-streeting with manual point-by-point matching, the new adjusting is decomposed into a series of optimal topological sub-mapping on relative sub-map region. Based on pinpointing one sample point to its accuracy location, the sub-mapping adjusts all nodes within the sub-map region.

This paper argues that electric map is formed to an image on the retina, takes the study of image processing and visual physiology as reference, and presents a new quantitative measurement of electric map information. Shape, color, texture and spatial relation are four factors deciding map information. The formula is given also.

Contour line is a closed curve that joined by points of the same elevation. This paper puts forward a new algorithm of creating contour line based on DEM, which uses the method of tracking the same elevation point to study the algorithm based on regular grid. This paper will be divided the algorithm of creating contour line into four sub-algorithms, namely: the algorithm of elevation comparison, the algorithm of calculating the same elevation point coordinates, the algorithm of tracking next point of the same elevation, the algorithm of tracking contour line. The algorithm of elevation comparison is mainly used in judging whether a contour line with appointed elevation passes through a side of the grid; the algorithm of calculating the same elevation point coordinates is used to calculate coordinates of contour lines across the grid's side; function of the algorithm of tracking next point of the same elevation is to track next point of the same elevation by following the trend of contour lines; the algorithm of tracking contour line aims in tracking coordinates of the point which has the equal value of elevation with the point in row x and column y.

The daintily and efficiency of electronic atlas visualization are all along the aim of designers and users. But nowadays most of GIS soft wares adopt GDI mode to display electronic atlas. On account of the localization of GDI, it restricts the beauty and effect of electronic atlas. As the upgrade of GDI, the function of GDI+ is very powerful. Aim at the characteristics of GDI+, the writer introduces the application of GDI+ in electronic atlas visualization detailed, includes advancing of program efficiency, improving of displaying effect and displaying transmutative annotations.

As an emerging field, cognitive map kept playing a significant role in geography these decades. To date, there are two dominant methods to externalize human's internal cognitive map, namely, multidimensional scaling (MDS) and skech mapping. However, among most recent researches on cognitive map, the differences between both methods are always ignored. The usage of one method over another is still under scrutiny. In order to shed light on the similarity or distinctions of MDS configuration and sketch mapping, we conducted an experiment on Beijing residents by requesting a sketch of the region within 3rd Ring and meanwhile extracting distance estimates between 8 landmarks. Employing the Bidimensional regression along with standard deviational ellipse, we studied the global and local distortions among two kinds of cognitive maps and quantitatively measure the overall and local cognitive maps distortions. Besides, we use Monte Carlo simulation method to calculate the radius of distortion for the Distortion Index (DI). It shows that the average cognitive distortion of habitants in Beijing is 2km to 3km, and the distortion takes 2nd-ring road as a border, displaying a southwest-northeast diagonal stretch and an east-west contracted tendency. The distortion in the two methods is remarkably both correlated with factors, such as travel frequency and years of residence. Comparing two methods, it turned out that sketch map was more consistent with real map, while the distortion orientations of sketch map resembled MDS configuration. Finally, we gave possible reasons with regard to above conclusions and advices for future usage of two methods.

Map presentation of geographical information based on GIS is an urgent problem lying in current GIS and cartography. Handling of features' relationship is the key in automatic-mapping. However, the discover and disposal of spatial conflict is the lowest degree of automation in cartography. A lot of work is still in handwork. After analyzing the data in the scale of 1:50,000 and 1:250,000, this article summarizes the relationship of cartographic features as overlapping-relation, attachment-relation and collision-relation. Combined with the data, the article put forward the method which is related to each of relationship.

As the development of thematic map design and mapping, the trend of geosciences knowledge and cartographic mapping knowledge representation is becoming formalized and quantified. This research is aimed to discuss application of geosciences knowledge and cartographic mapping knowledge in thematic map design, to investigate classification and representation method of them, and to analyze their practicability and efficiency in thematic mapping intellectualization design. It could be used as basis for decision making in automatic thematic map design. This research proposed the Thematic Mapping Intellectualization Design Model (TMIDM), which is the key issue for thematic mapping intellectualization. And geosciences knowledge and cartographic mapping knowledge application models for thematic mapping intellectualization design were also discussed.

Landform feature points and lines have been used as basic landform descriptors of landform skeleton in many fields, including surveying, simulation of hydrology, landform classification, and vegetation mapping. With the objective of landform classification from DEMs, an approach has been put forward based on topological parameters and the extended ones. The methodology for landform classification is implemented as a three-step process: choice of appropriate scale for analysis, extraction of feature lines, and quantitative measurement of feature lines. Five parameters, entropy of graphs, edge adjacency index and elevation difference weighted adjacency index, number graphs and density of graphs are used to classify different landforms. The result shows that topological index and descriptive parameters of graphs, aided by mean elevation is capable to classify of the high mountain, Loess Mao, Loess Liang and Low mountain.

Building detection and extraction from digital surface model (DSM) becomes more and more attracted when high resolution airborn radar and CCD sensor find their more applications in photogrammetric field. Because DSM contains the terrain heights, we firstly derive DTM from DSM, and then generate Normalized DSM (NDSM). The buildings are extracted from NDSM. However, since urban appearance is complex, with large buildings, small buildings, trees in mass, etc., building extraction is implemented through several stages. Local Surface Normal Angle Transform (LSNAT) is implemented to the height field. Big buildings are distinguished from other large regions generated from binary NDSM. Watershed segmentation is used to detect trees in mass together with LSNAT. Roofs of the small building are extracted based on the histogram of LSNAT. A case study is presented and analyzed in the end of this paper.

Map annotation is an important information representation method in computer-aided cartography and GIS. It is a supplement for map symbol system. With the development of computer technology, the Automatic Placemen of Annotation for map becomes a hotspot subject in computer-aided cartography. Usually, map Annotation is divided into three kinds: point feature, line feature and area feature. Specifically, the Placement of Annotation in Area Feature has being discussed by some scholars and many kinds of algorithms are given, mainly referring to the angle of the Annotation Placement. This paper discusses the Placement of Annotation in Area Feature within a point of view of the spatial geometric structure of the map, gives a new algorithm based on Map Spatial Geometry Information Measurement to complete the placement of annotation and compares the research results with the others.

In this paper, mapping and cartography in historical geography research are topic subjects. The authors take efforts to talk over the relationships of GIS and cartography, historical map and ancient map, historical map and contemporary map. On the basis of historical geography studies, the compiling of Liuchao-Jiankang historical map is discussed in details. In fact, a case study on compiling of the Distribution Density Map of Yangzhou' Registered Residences show clearly the methods and related digital technologies on historical geography mapping.

The paper describes an extended arc data structure, it is especially suitable in some vector-based operations. The existing vectorial arc data structure can store and organize coordinate information effectively, but some vector-based calculations are inefficient. Enlightened by the idea of spatial index, the paper proposed to divide arc into subsections, obtain spatial limit information of each segment and build up to arc data structure. The paper also gives realizing method for this modified structure, analyses time efficiency and space efficiency in some frequently used procedures. Taking the computation of the distance between point and arc for example, this paper analyses the relationship between computational efficiency and sub-arc node number, gives practical results using artificial and real arcs from a GIS environment. Tests results indicated that it would improve the efficiency of vector operations, and accelerate some vector-based algorithm practical indirectly with the extended data structure.