A formal framework for the representation of stack-based terrains

This paper presents a formal framework for the representation of three-dimensional geospatial data and the definition of common geographic information system (GIS) spatial operations. We use the compact stack-based representation of terrains (SBRT) in order to model geological volumetric data, both at the surface and subsurface levels, thus preventing the large storage requirements of regular voxel models. The main contribution of this paper is fitting the SBRT into the geo-atom theory in a seamless way, providing it with a sound formal geographic foundation. In addition we have defined a set of common spatial operations on this representation using the tools provided by map algebra. More complex geoprocessing operations or geophysical simulations using the SBRT as representation can be implemented as a composition of these fundamental operations. Finally a data model and an implementation extending the coverage concept provided by the Geography Markup Language standard are suggested. Geoscientists and GIS professionals can take advantage of this model to exchange and reuse geoinformation within a well-specified framework.     

Multi-criteria modelling and clustering of spatial information

To improve the formal integration of verbally given spatial information in a geographical information system, a methodology for converting such information to a geographical representation was developed. This was applied to examples of a spatial-related analysis of natural language text messages in the domain of disaster management. This article presents an approach for such a conversion by using a suitable knowledge representation as well as formal modelling structures. The structures are provided by an ontology-supported knowledge base. With respect to spatial uncertainty, a formal representation based on possibility theory was defined. Moreover, a cluster algorithm was developed for handling information of different sources and building a spatial context.     

认知地图的空间句法研究

将意识层面的空间意象外化为可被度量及分析的对象,一直是行为学、地理学、旅游学等学科关注的重要课题。本文主要从构建空间意象的结构而非意义入手,对该领域研究中的两种重要方法,即认知地图法和空间句法进行了比较,意图找到两种方法在空间结构性认知方面的相关性。基于句法空间结构的表达模型,分别就长沙太平街历史街区集成度及其认知地图的调研结果进行了比对,通过真实地图句法集成度与579 份认知地图意象要素出现频率等指标的比较,发现集成度指标与意象出现频率等指标存在较好的相关性。在对认知地图样本进行轴线化转换并比照真实地图的轴线索引后,对真实地图句法集成度与579 份认知地图平均句法集成度进行比较,发现认知地图与真实地图的句法分析在结果上仍有较好的相关性,且节点、标志物两要素的出现频次等指标也与所在街道的集成度存在较为明显的对应性。结论说明空间构形对人们结构性意象的形成有着重要的影响力,认知地图的句法分析对揭示人们空间知识的形成机制具有一定的参考价值,两种方法有相互补充的可能性。     

A metaheuristic approach for efficient and effective sketch-to-metric map alignment

Sketching as a natural mode for human communication and creative processes presents opportunities for improving human–computer interaction in geospatial information systems. However, to use a sketch map as user input, it must be localized within the underlying spatial data set of the information system, the base metric map. This can be achieved by a matching process called qualitative map alignment in which qualitative spatial representations of the two input maps are used to establish correspondences between each sketched object and one or more objects in the metric map. The challenge is that, to the best of our knowledge, no method for matching qualitative spatial representations suggested so far is applicable in realistic scenarios due to excessively long runtimes, incorrect algorithm design or the inability to use more than one spatial aspect at a time. We address these challenges with a metaheuristic algorithm which uses novel data structures to match qualitative spatial representations of a pair of maps. We present the design, data structures and performance evaluation of the algorithm using real-world sketch and metric maps as well as on synthetic data. Our algorithm is novel in two main aspects. Firstly, it employs a novel system of matrices known as local compatibility matrices, which facilitate the computation of estimates for the future size of a partial alignment and allow several types of constraints to be used at the same time. Secondly, the heuristic it computes has a higher accuracy than the state-of-the-art heuristic for this task, yet requires less computation. Our algorithm is also a general method for matching labelled graphs, a special case of which is the one involving complete graphs whose edges are labelled with spatial relations. The results of our evaluation demonstrate practical runtime performance and high solution quality.     

Sketch Maps and Qualitative GIS: Using Cartographies of Individual Spatial Narratives in Geographic Research

Mental and sketch maps have a long tradition in modern geography. Little theoretical and methodological distinction has been made, however, between different hand mapping approaches. Mental maps emerged from behavioral geography of the spatial science tradition as a technique to understand human behaviors based on peoples’ perceptions of their spatial environment. More recently, sketch maps have been used in participatory and qualitative geographic information systems (QGIS) to develop cartographies of group and individual spatial narratives. They are a tool that helps achieve QGIS's objectives of collecting unique spatial data of individual experiences, visualizing socio-spatial processes, breaking down particular barriers of positionality in research, and developing new uses of GIS. Two case studies illustrate the use of sketch maps in research, including a project examining job accessibility among working poor individuals and a study of the experiences of fear and safety in public spaces among lesbian, gay, bisexual, and transgender community members. Sketch maps in QGIS have many methodological merits. They add an invaluable dimension to the qualitative interview process, offer countermapping perspectives, generate detailed spatial information of individuals, and facilitate data interpretation.     

海岸带遥感资源调查的计算机解译方法探讨

该文介绍了一种利用计算机遥感图像解译进行资源调查的方法———斑块边界自动矢量化辅以目视栅格图像校正法。解译的主要步骤包括 :建立解译标志、影像配准、数据分析、图像增强、监督分类、目视解译修正、草图输出、实地检验、栅格转矢量、结果输出等。笔者结合案例对每一步出现的问题及其解决方法进行了探讨 ,并取得了海岸带资源遥感调查蓬莱幅的结果     

An evaluation of ontology matching techniques on geospatial ontologies

Standardization is one of the pillars of interoperability. In this context, efforts promoted by the Open Geospatial Consortium, such as CityGML (Technical University, Berlin), a standard for exchanging three-dimensional models or urban city objects, are welcomed. However, information from other domains of interest (e.g. energy efficiency or building information modeling) is needed for tasks such as land planning, large-scale flooding analysis, or demand/supply energy simulations. CityGML allows extension in order to integrate information from other domains, but the development process is expensive because there is no way to perform it automatically. The discovery of correspondences between CityGML concepts and other domains concepts poses a significant challenge.

Ontology matching is the research field emerged from the Semantic Web to address automatic ontology integration. Using the ontology underlying CityGML and the ontologies which model other domains of interest, ontology matching would be able to find the correspondences that would permit the integration in a more automatic manner than it is done now.

In this paper, we evaluate if ontology matching techniques allow performing an automatic integration of geospatial information modeled from different viewpoints. In order to achieve this, an evaluation methodology was designed, and it was applied to the discovery of relationships between CityGML and ontologies coming from the building information modeling and Geospatial Semantic Web domains. The methodology and the results of the evaluation are presented. The best results have been achieved using string-based techniques, while matching systems give the worst precision and recall. Only in a few cases the values are over 50%, which shows the limitations when these techniques are applied to ontologies with a partial overlap.     

Formal representation of qualitative direction

This paper reviews formal approaches to representing spatial knowledge about qualitative direction. Unlike geometric direction information, qualitative information does not employ numerical values but relies on comparison. The qualitative approach is often regarded as suitable for capturing commonsense concepts and thus is relevant to human-centered interfaces for spatial information systems. To establish a context for the work on qualitative direction, we preset a brief history of the development of qualitative temporal and spatial representations from different scientific perspectives. We identify main focal areas of these representations of spatial direction and propose a taxonomy. In the light of more than three decades of fruitful research, we obtain a map of formal representations that reveal interrelationships between different research strands in the field.     

Does base map size and imagery matter in sketch mapping?

Sketch mapping has been an important data collection technique for geographers since the 1960s. Structured sketch mapping requires participants to draw spatial data onto a base map containing cartographic information, in order to assist with spatial referencing. A concern that base map characteristics may influence sketch map content has been raised repeatedly in the research literature. However little scholarly attention has been paid to systematically testing the effect of base maps.This paper aims to test the effects of base map size and imagery on structured sketch maps of avoidance behaviour in university students. Using an experimental design, 272 sketch maps were compared for differences in: sketch map style; the location of collective avoidance hotspots; the extent of the reported area avoided; the number of reported areas avoided; the intensity of avoidance; and the tortuosity of sketch map features.No significant differences were found between base maps in sketch map style or the size, intensity or number of areas avoided. Provision of larger base maps caused respondents to draw more detailed sketch maps. Collective avoidance hotspots shifted location slightly between base maps, probably due to difficulties interpreting aerial photographs.Sketch map content appears to be remarkably robust to changes in base map. Base maps appear to assist respondents with spatial referencing rather than cueing respondents to report specific features.     

Integration of multi-source remote sensing data for land cover change detection

The objective of this study is to develop a methodology to integrate multi-source remote sensing data into a homogeneous time series of land cover maps in order to carry out change detection. We developed a method to increase the comparability between land cover maps coming from panchromatic aerial photographs and SPOT XS (multi-spectral) data by equalizing their levels of thematic content and spatial details. The methodology was based on the hypotheses that: (1) map generalization can improve the integration of data for change detection purpose, and (2) the spatial structure of a land cover map, as measured by a set of landscape metrics, is an indicator of the level of generalization of that map. Firstly, the methodology for data integration was developed by using land cover maps generated from near-synchronous data. Results revealed that, by controlling successively the parameters that influence the level of map generalization, the percentage of agreement between the near-synchronous land cover maps can be increased from 42% to 93%. The computation of five landscape metrics for a set of generalized land cover maps and for the target map allowed us to optimize the level of generalization by measuring the similarity in landscape pattern of the maps. The optimum level of generalization of the land cover map obtained from the aerial photographs for comparison with a land cover map derived from SPOT XS data was found at a resolution of 41m for two generalization levels of the thematic content. The spatial structure of a land cover map, as measured by a set of landscape metrics, is thus a good indicator of the level of generalization of this map. Secondly, the method was applied by integrating a land cover map obtained from aerial photographs of 1954 with a land cover map obtained from a SPOT XS image of 1992.     

Quantitative measures for spatial information of maps

The map is a medium for recording geographical information. The information contents of a map are of interest to spatial information scientists. In this paper, existing quantitative measures for map information are evaluated. It is pointed out that these are only measures for statistical information and some sort of topological information. However, these measures have not taken into consideration the spaces occupied by map symbols and the spatial distribution of these symbols. As a result, a set of new quantitative measures is proposed, for metric information, topological information and thematic information. An experimental evaluation is also conducted. Results show that the metric information is more meaningful than statistical information, and the new index for topological information is more meaningful than the existing one. It is also found that the new measure for thematic information is useful in practice.     

COMPARING DISTORTION ON SKETCH MAPS AND MDS CONFIGURATIONS*

The mental images on which an individual bases spatial decisions are often distorted versions of real-world geography. Distortion in these images is studied by extracting paired distance estimates and by requesting a sketch of a place drawn from memory. Reliance upon either technique to elicit large-scale spatial information assumes that distortion in the congnitive map is not introduced by the technique (sketching or configuration) used to construct it. Both techniques have been used in this study to produce cognitive maps for a common set of landmarks in Seattle. Map distortions are analyzed and compared to determine that significant differences result from the technique used.     

南北过渡带1∶5万植被类型图遥感制图案例研究

编制南北过渡带地区1∶25万和典型山地1∶5万植被类型图是南北过渡带综合科学考察的主要任务之一。以往植被类型图的编制都是采用大量的地面调查来完成的,地面调查方法虽然精确,但费时费力,并且由于自然条件的限制,地面调查往往只能覆盖较小的范围。遥感数据因为其全覆盖的优势,可以很好地弥补样方调查的局限性,但目前大范围的植被类型遥感信息提取尤其是自动提取方面仍然存在一定的困难和瓶颈。本文以1∶5万太白山植被类型图的编制为例,利用多源多时相的高分辨率遥感数据,结合地面调查数据、以往的各种比例尺的植被类型图数据和森林资源调查数据等,探讨并研究基于山地垂直带谱的中大比例尺植被类型图的遥感提取方法和制图方法。研究结果表明：① 山地植被垂直带谱可以有效地支持1∶5万山区植被类型图的遥感制图。利用太白山植被垂直带谱和1∶1万数字表面模型数据（DSM）可以生成具有垂直带谱信息的地形约束因子;将地形约束因子与多源多时相高分辨率遥感数据、地面调查数据、以往的小比例尺植被类型图数据等相结合,可以有效提取各级植被类型,从而实现中大比例尺植被类型图的编制。② 典型山地1∶5万植被类型图的遥感制图基本流程为植被型组解译→植被群系组、群系、亚群系解译→植被型、植被亚型分类,采取自上而下和自下而上相结合的分类方法来分类。本文的研究成果可以为中大比例尺植被类型图的编制提供示范和科学依据。     

The representation of geoscience information for data integration

In mineral exploration, resource assessment, or natural hazard assessment, many layers of geoscience maps such as lithology, structure, geophysics, geochemistry, hydrology, slope stability, mineral deposits, and preprocessed remotely sensed data can be used as evidence to delineate potential areas for further investigation. Today's PC-based data base management systems, statistical packages, spreadsheets, image processing systems, and geographical information systems provide almost unlimited capabilities of manipulating data. Generally such manipulations make a strategic separation of spatial and nonspatial attributes, which are conveniently linked in relational data bases. The first step in integration procedures usually consists of studying the individual charateristics of map features and interrelationships, and then representing them in numerical form (statistics) for finding the areas of high potential (or impact).Data representation is a transformation of our experience of the real world into a computational domain. As such, it must comply with models and rules to provide us with useful information. Quantitative representation of spatially distributed map patterns or phenomena plays a pivotal role in integration because it also determines the types of combination rules applied to them.Three representation methods—probability measures, Dempster-Shafer belief functions, and membership functions in fuzzy sets—and their corresponding estimation procedures are presented here with analyses of the implications and of the assumptions that are required in each approach to thematic mapping. Difficulties associated with the construction of probability measures, belief functions, and membership functions are also discussed; alternative procedures to overcome these difficulties are proposed. These proposed techniques are illustrated by using a simple, artificially constructed data set.     

AN APPROACH TO REPRESENTING THE SPATIAL STRUCTURE OF THE INFORMATION SOCIETY

With recent advances in information and communications technologies (ICT), traditional conceptualizations and models of spatial interaction need updating. In a previous paper, this author developed an analytical framework that incorporated telecommunications capabilities as well as transportation modes and residential and work locations into a unified representation of the “geography of opportunities” (Shen, 1999). In this paper, the initial framework is extended by the inclusion in the formulation not only of employment opportunities, but also of other types of opportunities. Each type of opportunities is distributed among three components of geographic space: the physical space, the hybrid space, and the virtual space. The effects of ICT are captured by: (1) the saving of travel time for people who can partially substitute telecommunications for transportation as means to access opportunities in virtual and hybrid spaces and (2) the migration of opportunities from physical space to virtual and hybrid spaces. Individuals' position in the emerging spatial structure of the information society is measured in terms of accessibility to a wide range of economic and social opportunities. This new approach is shown to be an operational and promising analytical tool in a hypothetical setting. However, its refinement and application is currently constrained by the lack of systematically collected data on many aspects of the human geography. [Key words: telecommunications, human geography, spatial structure, spatial analysis.]     

多尺度地图空间相似关系基本问题研究

基于多尺度地图数据库建设中地图自动综合的终止判断条件,引出多尺度地图空间相似关系问题。基于集合论给出空间相似关系的定义,论述空间相似关系的5个性质,即反身性、对称性、非传递性、多尺度自相似性与尺度依赖性;并从图形相似和属性相似的角度论述多尺度地图空间相似关系的分类体系。该成果是研究地图自动综合和地图空间相似查询等的基础。     

数字高程模型在活动断层位置及地表变形变位特征提取研究中的应用

活动断层的位置分布及其地表变形变位特征的准确识别是研究和评价活动断层的基础,国内外学者利用数字高程模型(DEM)对断层提取进行了大量研究。本文基于DEM的活动断层位置的提取方法进行综述,总结了DEM提取断层位置的地貌形态特征分析、图像处理以及综合处理提取方法,突出介绍了高分辨率DEM在详细的断层位置分布提取中的优势,DEM在断层地表变形变位及其特征参数提取研究中的最新应用进展。随着高分辨率DEM的快速发展,DEM及其空间分析技术已成为一种常见的地学研究方法,将其与野外调查、遥感、测年等技术结合进行综合分析,能够促进对活动断层的深入研究,并成为断层定量化研究强有力的技术手段。     

Same space – different perspectives: comparative analysis of geographic context through sketch maps and spatial video geonarratives

ABSTRACT

The importance of including a contextual underpinning to the spatial analysis of social data is gaining traction in the spatial science community. The challenge, though, is how to capture these data in a rigorous manner that is translational. One method that has shown promise in achieving this aim is the spatial video geonarrative (SVG), and in this paper we pose questions that advance the science of geonarratives through a case study of criminal ex-offenders. Eleven ex-offenders provided sketch maps and SVGs identifying high-crime areas of their community. Wordmapper software was used to map and classify the SVG content; its spatial filter extension was used for hot spot mapping with statistical significance tested using Monte Carlo simulations. Then, each subject’s sketch map and SVG were compared. Results reveal that SVGs consistently produce finer spatial-scale data and more locations of relevance than the sketch maps. SVGs also provide explanation of spatial-temporal processes and causal mechanisms linked to specific places, which are not evident in the sketch maps. SVG can be a rigorous translational method for collecting data on the geographic context of many phenomena. Therefore, this paper makes an important advance in understanding how environmentally immersive methods contribute to the understanding of geographic context.