Chapter Overview
說明本章的各節的內容及主要概念，使用的方式為：
1. 開始閱讀正文前，閱讀概要，瞭解本章的目的，試試和以前學過的相關知識連結。
2. 正文閱讀後，回頭看章節概覽，幫助將本章所有內容，整理成有系統的架構，並且藉以驗證是否瞭解本章內容。
3. 複習時，能夠默寫出OverView的大意。
Chapter Overview
This book covers thematic mapping and the associated expanding area of geographic visualization (or "geovisualization"). A thematic map (or statistical map) is used to display the spatial pattern of a theme or attribute. A familiar example is the temperature map shown in daily newspapers; the theme (or attribute) in this case is the predicted high temperature for the day. The notion of a thematic map is described in section 1.1 and contrasted with the general-reference map, which focuses on geographic location as opposed to spatial pattern (e.g., a topographic map might show the location of rivers).ln section 1.2 the different uses for thematic maps are described: to provide specific information about particular locations, to provide general information about spatial patterns, and tocompare patterns on two or more maps.
An important function of this book is to assist you in selecting appropriate techniques for symbolizing spatial data. For example, imagine that you wish to depict the amount of forest cleared for agriculture in each country during the preceding year, and have been told that the number of acres of forest cleared by country is available on the Web. You wonder whether additional data (e.g., the total acres of land in each country) should be collected and how the resulting data should be symbolized. Section 1.3 presents steps that assist you in tackling such problems, and ultimately that enable you to communicate the desired information to map readers. These steps are as follows: (1) consider the real-world distribution of the phenomenon, (2) determine the purpose for making the map, (3) collect data appropriate for the map purpose, (4) design and construct the map, and (5) determine whether users find the map useful and informative. Despite some criticism of the appropriateness of such steps, they are helpful in avoiding the design blunders that can result from using the most readily available data and software.
Like many disciplines, the field of cartography has undergone major technological changes. As recently as the 1970s, most maps were still produced by manual and photomechanical methods, whereas today, nearly all maps are produced using computer technology. Section 1.4 considers some of the consequences of this technological change, including (1) the ability of virtually anyone to create maps using personal computers; (2) new mapping methods, such as animated maps; (3) the ability to explore geographic data in an interactive graphics environment; (4) the ability to link maps, text, pictures, video, and sound in multimedia presentations; (5) the ability to create realistic representations of the environment (virtual environments or virtual reality) and the related notion ofaugmented reality (i.e., enhancing our view of the real world through computer- based information); and (6) the ability to access maps and related information via the Web.
In section 1.5 we consider the origin and definition of geographic visualization. The term "visualization" has its roots in scientific visualization, which was developed outside geography to explore large multivariate data sets, such as those associated with medical imaging, molecular structure, and fluid flows. Borrowing from these ideas, geographers have created the notion of geographic visualization(or geovisualization), which can be defined as a private activity in which unknowns are revealed in a highly interactive environment. Communication on traditional printed maps involves the opposite: It is a public activity in which knowns are presented in a noninteractive environment.
Although our emphasis in this book is on cartography, we want you to be aware of developments in the broader realm of geographic information science (GIScience), which can be considered to include cartography and the techniques of geographic information systems (GIS), remote sensing, and quantitative methods. In section 1.6, we consider the increased capability provided by GIS and remote sensing, which allow us to create detailed maps more easily than was possible with manual techniques. GIS accomplishes this through its extensive spatial analysis capabilities, and remote sensing allows us to "sense" the environment, particularly outside our normal visual capabilities (e.g., detecting previsual levels of vegetation stress). The major development in quantitative methods relevant to cartography is that of exploratory spatial data analysis (ESDA), which has close ties with the notion of data exploration that cartographers utilize.
While technological advances have had a major impact on cartography, the discipline has also experienced changes in its philosophical outlook. Section 1.7 deals with the increasing role thatcognition now plays in cartography. Traditionally, cartographers approached mapping with a behaviorist view, in which the human mind was treated like a black box. Today cartographers take a cognitive view, in which they hope to learn why symbols work effectively. Section 1.8 deals with social and ethical issues in cartography-there we will see that maps often have hidden agendas and meanings, and that our increasing technological capability provides tremendous opportunity, but also is fraught with potential problems (e.g., the notion of geoslavery).