GIS结点捕捉的广义算法及误差传播模型

根据最小二乘原理，本文提出了结点捕捉的一种广义算法，并建立了伴随的误差传播模型，针对位于模糊公差范围内待捕捉点组中各点坐标误差统计我的各种可能的特殊情况，进一步导出了相应的简化算法以及其误差传播模型，并从理论和数值模拟两方面系统地分析了结点坐标的相准确性一对捕捉结果的影响，理论推导表明，现有的GIS结点捕捉算法属广义算法的一种特殊情况，最后通过算例说明了广义算法和误差传播模型的实际应用前景。     

A spatial contextual immune genetic algorithm to building cartographic displacement

In map generalization, displacement is the most frequently used operator to reduce the proximity conflicts caused by reducing scales or other generalization operations. Building displacement can be formalized as a combinatorial optimization problem, and a heuristic or intelligent search algorithm can be borrowed to obtain the solution. In this way, we can explicitly resolve minimum distance conflicts and control positional accuracy during the displacement. However, maintaining spatial relations and patterns of buildings can be challenging. To address spatial conflicts as well as preserve the significant spatial relations and patterns of buildings, we propose a new spatial contextual displacement algorithm based on an immune genetic algorithm. To preserve important spatial relations and global patterns of map objects and avoid topology errors, displacement safety zones are constructed by overlapping the Voronoi tessellation and buffer areas of the buildings. Additionally, a strategy to shift the buildings in a building group synchronously is used to maintain local building patterns. To demonstrate the effectiveness of our algorithm, two data sets with different building densities were tested. The results indicate that the new algorithm has obvious advantages in preventing topology errors and preserving spatial relations and patterns.     

基于尺度的GIS空间资料表达模型

介绍了基于层的GIS空间资料表达方法易于进行空间查询与空间分析处理的优点,针对其引起的地图难以进行扩展与图像显示转换困难的缺点,提出了基于尺度(比例尺)的空间资料表达新方法.在基于尺度的空间资料表达方法中,地图可以由空间对象,区域,尺度视图三级尺度模型表达.对尺度方法下的地图结构,地图组织,指标结构,地图扩展等在理论上作了探讨,提出了基于尺度的方法与已广为使用的基于层的方法的有效集合,将有可能成为地理信息表达研究的最重要研究方向.     

施工总图空间数据结构研究

根据系统空间数据结构的特点 ,提出了图块_实体数据模型 ,有效地解决了对空间信息操作的复杂性 ,有利于施工中空间数据的动态更新和维护。该系统的空间数据结构为相关信息系统建立适宜的空间数据结构提供了一条可行的途径。     

中误差和邻近关系的多尺度面实体匹配算法研究

地图目标匹配作为空间数据整合和更新的一个不可缺少的过程,有重要的研究意义。中误差是一种衡量地图精度和质量的数值指标,其范围作为制图和综合的重要的标准之一,常用其大小评价空间数据的质量,不同比例尺或来源的地图数据均有不同的中误差大小和阈值。面状要素在很多地图中占有很大的比例,本文将中误差引入面实体匹配的过程,结合相邻面实体邻近聚集算法,提出一种基于中误差和邻近关系的面实体匹配算法,可以有效解决多尺度空间数据匹配的阈值大小和多对多关系难确定的问题,实验结果表明该方法具有良好的稳定性和可靠性。     

Analysing Product-Specific Behaviour to Support Process Dependent Updates in a Dynamic Spatial Updating Model

A scale‐independent database that allows derived maps to be dynamically updated from a centrally maintained data source is an appealing alternative to traditional map revision techniques, which by today's standards are costly and inefficient. This paper presents a dynamic spatial updating model that supports automated updating of non‐standard maps in a scale‐independent database‐centric map production environment. Maps derived from the database are not separate data sets, but rather active views of the database. Each derived map is displayed in a unique way by implementing cartographic operations at the map level. While the operations applied require user involvement for strategic cartographic decisions, and algorithmic initiation and control, the technique allows geographic data to be processed cartographically without affecting the geometric integrity of the database. Each time a derived map is opened it retrieves the spatial data (and updates) from the database and applies the unique cartographic representation methods that persist on the individual derived maps. Database updates are automatically triggered to cartographic products, as process dependent updates, according to their individual product‐specific behaviour. This paper investigates product‐specific behaviour (product multiplicities) and the cartographic processing requirements to support dynamic spatial updating techniques in an object‐oriented map publishing environment. These techniques are implemented in an off‐the‐shelf software environment using ArcGIS.     

Mapping deer habitat suitability using remote sensing and geographic information systems

This paper describes an effort to map the habitat for the Eastern Tehama Deer Herd located in Northern California. The range of this herd encompasses almost 600,000 hectares (1.5 million acres). Knowledge of the spatial distribution of suitable habitat is prerequisite to managing the deer herd. Remote sensing and GIS are appropriate tools for such an assessment. Remotely sensed data were used to map vegetation/land cover. These data along with elevation, aspect, slope, juxtaposition, and various buffer zones were input into a GIS and a model was used to produce a map of habitat suitability. The accuracy of the vegetation/land cover map was assessed and methods for validating the habitat suitability map are presented.     

MapInfo系统线(面)目标缓冲区构建模型存在的问题及其改进方法

通过对由MapInfo系统生成的几个典型的点和线(面)目标缓冲区实例的深入剖析,发现了MapInfo系统在线(面)目标缓冲区构建模型中存在的问题。在对其原因进行深入分析与验证的基础上,给出了具体的改进思路和方法。一方面为GIS用户避免对MapInfo系统的线(面)目标缓冲区分析工具的滥用,以及提高空间分析的精度和可信度提供了具体的改进方法与建议;另一方面又为有关软件开发人员研制新版MapInfo系统及其他GIS软件提供了有益的参考。     

A map‐algebra‐based method for automatic change detection and spatial data updating across multiple scales

The availability of geospatial data has increased significantly over recent decades. As a result, the question of how to update spatial data across different scales has become an attractive topic. One promising strategy is to use an updated larger‐scale dataset as a reference for detecting and updating changed objects represented in a to‐be‐updated smaller‐scale dataset. For such an update method, an understanding of the different types of changes that can occur is crucial. Using polygonal building data as an example, this study examines the various possible changes from different perspectives, such as the reasons for their occurrence, the forms in which they manifest, and their effects on output. Then, we apply map algebra theory to establish a cartographic model for updating polygonal building data. Supported by concepts of map algebra, an update procedure involving change detection, filtering, and fusion is implemented through a series of set operations. In addition to traditional polygon overlay functions, the constrained Delaunay triangulation model and knowledge of map generalization procedures are employed to construct set operations. The proposed method has been validated through tests using real‐world data. The experimental results show that our method is effective for updating 1:10k map data using 1:2k map data.     

一种用于空间数据整合的建筑物面实体对齐方法

提出了一种用于空间数据整合的建筑物面实体对齐方法,可用来改善空间数据的位置精度。首先,采用基于最小外接矩形（minimum bounding rectangle,MBR）组合优化算法的匹配方法识别整合数据之间的同名实体;然后,提出基于几何相似性的成对约束谱匹配算法检测1:1、1:N和M:N同名实体之间的共轭点对;针对1:N和M:N匹配中不可避免存在弱对应点对和错误对应点对的问题,提出基于IGG1权重的最小二乘法来有效对齐同名实体。将所提出的方法应用于对齐较高位置精度的基础测绘地图数据和较低位置精度的谷歌地图数据中,结果表明,该方法不仅可检测存在复杂轮廓对应的1:N和M:N同名实体的共轭点对,而且可实现它们之间的有效对齐,使同名实体的位置信息差异最小化。     

Shapes on a plane: evaluating the impact of projection distortion on spatial binning

ABSTRACT

One method for working with large, dense sets of spatial point data is to aggregate the measure of the data into polygonal containers, such as political boundaries, or into regular spatial bins such as triangles, squares, or hexagons. When mapping these aggregations, the map projection must inevitably distort relationships. This distortion can impact the reader’s ability to compare count and density measures across the map. Spatial binning, particularly via hexagons, is becoming a popular technique for displaying aggregate measures of point data sets. Increasingly, we see questionable use of the technique without attendant discussion of its hazards. In this work, we discuss when and why spatial binning works and how mapmakers can better understand the limitations caused by distortion from projecting to the plane. We introduce equations for evaluating distortion’s impact on one common projection (Web Mercator) and discuss how the methods used generalize to other projections. While we focus on hexagonal binning, these same considerations affect spatial bins of any shape, and more generally, any analysis of geographic data performed in planar space.     

基于弹性力学思想的居民地点群目标位移模型

本文引入弹性力学思想对空间目标进行冲突探测及受力分析 ,用空间距离聚类及建立最小生成树的方法把空间关系较近的、相互独立的点状要素聚类组合成多个有机的整体 ,对每个整体用有限元的方法通过多次迭代。本算法的实验结果满足了诸多的制图约束条件 ,能够很方便地应用在制图综合中的位移操作中     

基于SuperMap Deskpro & CorelDraw的电子地图制作——以上海长风公园导航地图为例

以上海长风公园导航地图的制作为例,探讨了结合GIS软件与传统绘图软件制作电子地图,提高电子地图可视化质量的方法;分析了电子地图制作过程中数据转换、地图配准等技术问题的处理措施.结合CorelDraw的绘图功能和SuperMap Deskpro的空间数据处理功能,可使导航电子地图的视觉效果明显增强.     

Exploiting IKONOS and Hyperion data fusion for automated road extraction

We present here the examples that show how fusing data from hyperspectral sensors with data from high spatial resolution sensors can enhance overall road detection accuracy. The fusion of hyperspectral and high spatial resolution data combines their superior respective spectral and spatial information. IKONOS (MSS) and Hyperion images were fused using the principal component analysis (PCA) method. The approach for road extraction integrates multiresolution segmentation and object oriented classification. Road extraction is done from an IKONOS (MSS) image and a Hyperion and IKONOS (MSS) merged image and comparisons are made depending on accuracy and quality measures such as completeness and correctness. This article also emphasises the types of roads which are giving better accuracy of extraction after fusion with hyperspectral image. This can vary because of types of material and condition of roads. The methodology was applied on roads of Dehradun, India.     

Building Displacement Based on the Topological Structure

Map data at smaller scales than their source can result in spatial conflict, whereby map symbols become too close, or overlaid. Server map generalisation operators may be applied to solve this problem, including displacement. In this paper, we show how an optimisation algorithm, the snake algorithm, was used to displace multiple objects in order to resolve spatial conflicts and maintain important spatial relationships between objects during displacement. Two principles based on the snake algorithm are proposed in this paper. First, the truss structure mirroring spatial proximity relationships between buildings and between building and road is formed based on the weighted proximity graph derived from constrained Delaunay triangulations (CDT) in each map partition. In the weighted proximity graph, each connecting line is determined as a snake and as an element unit to assemble the global stiffness matrix in snake algorithm. Second, a buffer method that calculates force between a building and a road (or other linear features) or between pair of buildings is adopted in the snake algorithm. This avoids the imbalance phenomenon caused by different force calculation methods during the displacement. The feasibility of the approach is demonstrated in obtaining real geographic data. Finally, the results are cartographically usable and in particular, the spatial relationships between objects are preserved.     

轨迹分割与图层融合的车辆轨迹线构建道路地图方法

传统道路地图构建方法将轨迹点（线）同等对待提取道路数据,忽略车辆轨迹的空间差异性,制约其结果精度与应用范围。为此,本文根据轨迹速度将轨迹线集分割滤选为3个轨迹线子集,将轨迹方向与Delaunay三角网模型集成探测路网拓扑结构;顾及轨迹线子集的特征差异选取不同参数值和约束条件并分层提取道路几何、交通语义数据,分别构建3个道路图层;运用缓冲区方法并根据道路几何、语义特征将多个道路图层融合为单个完整道路地图。运用出租车轨迹数据进行试验分析,结果表明：该方法顾及轨迹分布差异性,能将道路几何、交通语义信息融合提取,更适于处理复杂道路结构下的轨迹线。     

Measures of spatio-temporal accuracy for time series land cover data

Remote sensing is a useful tool for monitoring changes in land cover over time. The accuracy of such time-series analyses has hitherto only been assessed using confusion matrices. The matrix allows global measures of user, producer and overall accuracies to be generated, but lacks consideration of any spatial aspects of accuracy. It is well known that land cover errors are typically spatially auto-correlated and can have a distinct spatial distribution. As yet little work has considered the temporal dimension and investigated the persistence or errors in both geographic and temporal dimensions. Spatio-temporal errors can have a profound impact on both change detection and on environmental monitoring and modelling activities using land cover data. This study investigated methods for describing the spatio-temporal characteristics of classification accuracy. Annual thematic maps were created using a random forest classification of MODIS data over the Jakarta metropolitan areas for the period of 2001–2013. A logistic geographically weighted model was used to estimate annual spatial measures of user, producer and overall accuracies. A principal component analysis was then used to extract summaries of the multi-temporal accuracy. The results showed how the spatial distribution of user and producer accuracy varied over space and time, and overall spatial variance was confirmed by the principal component analysis. The results indicated that areas of homogeneous land cover were mapped with relatively high accuracy and low variability, and areas of mixed land cover with the opposite characteristics. A multi-temporal spatial approach to accuracy is shown to provide more informative measures of accuracy, allowing map producers and users to evaluate time series thematic maps more comprehensively than a standard confusion matrix approach. The need to identify suitable properties for a temporal kernel are discussed.     

空间分析方法在道路网自动综合拓扑构建中的应用

在道路网的自动综合中,一般的方法都必须对道路网进行自动拓扑生成,建立起点、线、面之间的关系,以利于道路选取时网眼的分析和选取后的路径分析。本文考虑到数字地图的数据特点,在进行道路网自动拓扑过程中,对经常遇到的线状要素无法合理构面的问题进行分析并提出了合理的解决方法。方法中主要运用了缓冲区分析和叠置分析,通过把居民地层数据叠置到道路层数据进行联合分析,为道路网的自动选取构建出了正确的空间拓扑关系。     

地图符号游程编码表达及其应用

地图符号化将抽象的空间数据转换为可见的地图,其结果以栅格结构存储,进行地图输出时受限于栅格数据量。压缩符号化后的栅格数据来降低计算机资源开销是提高地图输出效率的一种有效途径,据此本文提出利用游程编码表达地图符号的方法,建立面向符号的游程编码数据结构,利用直接的游程运算取代栅格运算来完成地图的各种操作,并在此基础上完成地图输出。该方法减少了数据冗余,直接的游程运算提高了运算粒度,可以满足高分辨率地图输出对处理效率和内存开销的要求。     

The effect of spatial autocorrelation and class proportion on the accuracy measures from different sampling designs

Four binary thematic maps with combinations of two spatial autocorrelation levels and two different class proportions are simulated to study their effect on the precision of accuracy measures from different sampling designs. A series of eleven sample sizes (from a minimum of 25 to a maximum of 1296) are simulated using three popular sampling designs, including simple random sampling (SRS), systematic sampling (SYS), and stratified random sampling (StrRS) on the four simulated maps. The conventional error matrix and related accuracy measures are calculated for each simulation, and the precision of different estimates of accuracy measures is compared among the three sampling designs.The selection of a particular sampling design and sample size depends on the spatial autocorrelation level, the class proportion difference, and the accuracy indices that a given application requires. In general, the class proportion difference has a greater impact on the performance of different sampling methods than the spatial autocorrelation level does on a map. For estimating the accuracy of individual classes, stratified sampling achieves better precision than SRS and SYS with smaller sample sizes, especially for estimating the small class. For estimating the overall accuracy, different sampling designs achieve very similar levels of precision with fewer samples. To achieve a better estimate of the kappa coefficient, stratified random sampling is recommended for use on a map with a high class proportion difference, while random sampling is preferred for a map with low spatial autocorrelation and a low class proportion difference.