伊犁河跨界流域土地利用变化特征分析

土地利用变化引发的水资源问题往往成为跨界流域各国矛盾的焦点,如何充分考虑跨界流域的特殊性和复杂性,对土地利用变化研究提出了新的要求。本文利用 MODIS产品提取了伊犁河流域2001-2009年土地利用数据,划分流域的产水/耗水区,结合流域跨界特点分析其土地利用变化特征。研究时段内,伊犁河流域土地利用以农田和天然植被为主,农田总面积有所下降,天然植被面积基本稳定。其中上中游产水区林地出现萎缩,草地面积增幅较大;中游水库耗水区内农田大幅度转化为天然植被;下游三角洲耗水区土地利用开发受限,人类干预程度下降。产流区内中国农田面积相对境外持续增加,而天然植被面积相对境外则持续缩小。受制度影响,哈萨克斯坦境内土地利用变化波动明显,中国境内土地利用变化幅度相对稳定。     

A modified binary space partitioning tree for geographic information systems

We present a reactive data structure, that is, a spatial data structure with detail levels. The two properties, spatial organization and detail levels, are the basis for a geographic information system (GIS) with a multi-scale database. A reactive data structure is a novel type of data structure catering to multiple detail levels with rapid responses to spatial queries. It is presented here as a modification of the binary space partitioning tree that includes the levels of detail. This tree is one of the few spatial data structures that does not organize space in a rectangular manner. A prototype system has been implemented. An important result of this implementation is that it shows that binary space partitioning trees of real maps have O(n) storage space complexity in contrast to the theoretical worst case O(n² ), with n the number of line segments in the map.     

Designing sound in cybercartography: from structured cinematic narratives to unpredictable sound/image interactions

In this paper we draw on the analysis of sound in film theory in order to explore the potential that sound offers cybercartography. We first argue that the theoretical body developed in film studies is highly relevant to the study of sound/image relationships in mapmaking. We then build on this argument to develop experimental animated and interactive sound maps for the Cybercartographic Atlas of Antarctica that further explore the potential of sound for integrating emotional, cultural and political dimensions in cartography. These maps have been designed to recreate cinematic soundscapes, to provide contrapuntal perspectives on the cartographic image and to generate an aural identity of the atlas. As part of this experimental mapping, an innovative sound infrastructure is being developed to allow complex sound designs to be transmitted over the Internet as part of atlas content. Through this infrastructure the user can select as well as contribute his own sounds. The overall cartographic message is becoming less predictable, thus opening new perspectives on the way we design, interact with, and modify sounded maps over the Internet.     

Possibilities and limits of prospective GIS land cover modelling—a compared case study: Garrotxes (France) and Alta Alpujarra Granadina (Spain)

This study focuses on the possibilities and the limits of a prospective GIS land cover modelling applied to two case studies (France and Spain). The methodology, based on available GIS tools, consists of using earlier land cover maps and relevant environmental factors (calibration data) to model actual, known land cover to validate the model. The model aggregates Markov chain analysis for time prediction and multi‐critera evaluation, multi‐objective evaluation and cellular automata to perform spatial contiguity of modelled land cover scores. The first results give an accurate, pixel by pixel prediction rate of approximately 75%. An important issue of this study consists of analysing prediction residues to improve the model.     

Modeling the scale dependences of topological relations between lines and regions induced by reduction of attributes

The scale dependences of topological relations are caused by the changes of spatial objects at different scales, which are induced by the reduction of attributes. Generally, the detailed partitions and multi-scale attributes are stored in spatial databases, while the coarse partitions are not. Consequently, the detailed topological relations can be computed and regarded as known information, while the coarse relations stay unknown. However, many applications (e.g., multi-scale spatial data query) need to deal with the topological relations at multiple scales. In this study new methods are proposed to model and derive the scale dependences of topological relations between lines and multi-scale region partitions. The scale dependences of topological relations are modeled and used to derive the relations between lines and coarse partitions from the relations about the detailed partitions. The derivation can be performed in two steps. At the first step, the topological dependences between a line and two meeting, covered and contained regions are computed and stored into composition tables, respectively. At the second step, a graph is used to represent the neighboring relations among the regions in a detailed partition. The scale dependences and detailed relations are then used to derive topological relations at the coarse level. Our methods can also be extended to handle the scale dependences of relations about disconnected regions, or the combinations of connected and disconnected regions. Because our methods use the scale dependences to derive relations at the coarse level, rather than generating coarse partition and computing the relations with geometric information, they are more efficient to support scale-dependent applications.     

Beyond the epsilon band: polygonal modeling of gradation/uncertainty in area-class maps

A spatial modeling technique is proposed to represent boundary uncertainty or gradation on area-class maps using a simple polygon tessellation with designated zones of indeterminacy or transition zones. The transition zone can be conceptualized as a dual of the epsilon band, but is more flexible and allows for a wide range of polygonal configurations, including polygons with sinuous boundaries, spurs, three-way transition zones, and null polygons. The model is specified using the medial axis to capture the general shape characteristics of a transition zone. Graph theoretic representation of an extended version of the medial axis captures key junctions in both shape and classification and is used to identify well-formed transition zones that can be logically and unambiguously handled by the model. A multivariate classification surface is specified by first defining degrees or probabilities of membership at every point on the medial axis and transition zone boundary. Degrees or probabilities of membership at all other points are defined by linear interpolation. The technique is illustrated with an example of a complex transition zone, and a simple isoline representation that can be derived from the model is presented. The proposed modeling technique promises to facilitate expert characterization of soil formations, ecological systems, and other types of areal units where gradation and/or boundary uncertainty are prevalent.     

A new algorithm for distance cartogram construction

A distance cartogram is a diagram that visualizes the proximity indices between points in a network, such as time–distances between cities. The Euclidean distances between the points on the distance cartogram represent the given proximity indices. This is a useful visualization tool for the level of service of transport, e.g. difference in the level of service between regions or points in a network and its improvement in the course of time. The two previously proposed methods—multidimensional scaling (MDS) and network time–space mapping—have certain advantages and disadvantages. However, we observe that these methods are essentially the same, and the merits of both these methods can be combined to formulate a generalized solution. In this study, we first formulate the time–space mapping problem, which includes the key features of both of the above stated methods, and propose a generalized solution. We then apply this solution to the time–distances of Japan's railway networks to confirm its applicability.     

高校“地图学”课程思政元素挖掘与课堂融入

高校专业课的课程思政建设是高校思想政治工作的基本载体。“地图学”是测绘工程、遥感科学与技术、地理信息科学、地理科学等本科专业的基础课,在测绘、地理等学科的课程思政建设中具有基础性地位。本文依据教学实践,归纳了地图学课程中与课程思政相结合的知识点,并介绍了在教学中如何巧妙、潜移默化地融入思政元素,在地图学课程教学过程中做到能力培养和素质提升共同进步。     

土地信息系统的设计原理

从土地信息的一般概念入手，提出了土地信息系统设计的基本内容，基本原则，并就系统数据的建立，数据的输入与输出，土地信息数据的标准化与规范化等进行了较深入的讨论。     

基于数据库存储方案的高性能瓦片地图服务研究

实时渲染与网络传输是影响WebGIS性能的两大因素,瓦片技术是改进系统性能的最佳选择,它通过对地图数据预先渲染、切片,有效减轻服务器处理压力,减少网络负载和响应延迟,但瓦片数据量庞大,磁盘存储碎片化,影响IO性能,数据可迁移性差,无论是数据备份、迁移或是恢复都耗时漫长。该文设计实现了一种新的基于文件数据库的瓦片存储方案,并将分布式缓存系统Memcached作为缓存支持集成在方案中,不仅克服了传统瓦片储存的缺陷,还在性能方面取得了优异的表现,是构建高性能瓦片地图服务的有益尝试。