Use Of Visual Variables Research Articles

The design of useful graphics in Bertin’s thought. A case study from the Urban Atlas of Jeddah

Abstract. The Semiology of Graphics of French cartographer J. Bertin is not only a seminal work on maps design, it contains also very useful sets of rules and insights that apply to graphics (BERTIN, 1970, 1973, 1987, 2005; DHIEB, 2018). Even though the visual variables are considered by cartographers as one of the most principal discoveries of the book (DE GOLBERY et al., (1996; PALSKY, 2017;), Bertin stated very useful techniques, innovations, artefacts and examples that apply specifically to the design of maps and graphics.One of the most important issues that were not discussed considering the visual variables and the overall design addresses the design of graphics and the use of visual variables. When handling statistical data to design graphics, these latter should not be built randomly; their design should obey strict rules and contain necessary components with regards to the data handled. May we talk about a kind of guideline to help users to choose the most efficient type of graphic depending on the data characteristics the design context, and the message to convey?Yet the specialized software dedicated to graphics design such as Excel do not answer this question and do not help sufficiently the map users to make the best choice and when a choice is made, a useful explanation is not furnished to justify this choice by common users or by cartographers. Our hypothesis is that the design of graphics and the choice of appropriate visual variables according to their properties is worth it: it may greatly influence their attractivity and increase their readability and memorization.This issue was encountered by authors when designing the Urban Atlas of Jeddah (UAJ). Besides detailed maps that portray the spatial distribution and analysis of various data on Jeddah and its districts, the UAJ needed that some of these data to be converted into graphics when the focus is on attribute characteristics rather than on spatial distribution. When inserted in one Atlas, the choice of one given type of graphics does not depends only on scientific criteria but also on design considerations (choice of appropriate visual variables, consistency, homogeneity, and relevance…). For instance, we should not put in one single atlas only one type of graphics, nor the same looks in terms of retained visual variables.Yet, the recent Arabic translation of the Semiology of Graphics (DHIEB, 2018) gave them very useful guidelines in designing Atlas graphics. The goal of this paper is first to put altogether Bertin’s principles and insights that should apply to the design of graphics; second to implement such guidelines in the UAJ project; and third to evaluate such uses stated 50 years ago by Bertin and other graphicians (BERTIN, 1970, 1973, 1987, 2005; BONIN, 1983; BONIN S. and BONIN M., 1989; GIMENO, 1980; BORD, 2000) with regards to the scientific and technical evolution of graphics design. Full automation of graphical design (GRONOFF, J.-D., 1983; MULLER, J.C., 1984) should be inspired by Bertin’s statements on the use of visual variables and the multiple rules that should be extracted from the Graphics Design Guideline (GDG) developed by the authors. Examples of simple graphics or of graphics processing (AMADO, 1994) from the UAJ are furnished according to the sets of prototypes of graphics realized.

Design Issues on Context-Based Cartographic Communication Using Extended Visual Variables

Abstract. Visual variables are the fundamental notion for the transcription of information or data into visual representation (Bertin, 1967). But if we introduce the notion of manipulation and communication of the visual representation, various situations will appear (Morita, 2011, 2018). Nowadays, we use many context-based cartographic communications in our information society using a network system, computer and mobile devices. In this context, information and communication are driven dynamically in response to the necessity of one’s activity in the real world. In cartographic communication, there are two levels of context. One is within the cartographic representation: the relationships between cartographic symbols on a map and the figure and background composed of symbols. The other context is map use: the relationship between a map and its surrounding environment in a specific situation of map use. Cartographic symbols are represented through the use of visual variables. But in context-based visual communication, visual variables have to be combined with other notions of visual manipulation for efficient representation. In the case of, for example, the scale selection, the synthesis of different visual variables, and the use of ideogrammatic symbols, complementary guidelines − especially regarding what you should not do − are needed for the practice of design process. What are the elements to be considered to this end?If the scale of map has to be changed, the problem of what is called ‘generalization’ will appear. The difference between zoom in/out and a scale change of more than ten times should be well recognized. In the latter case, signification of what is being represented might be changed. Name placement also has the same character. Each name has its own territory and they are arranged in a hierarchical structure. The most common inconvenience is the overlapping and congestion of symbols and letters. In a bad case, it is impossible to extract meanings from the dumpling zone, furthermore meaningless areas become no more than “noise”? Very often we meet this phenomenon in the application software of web-mapping (Figure 1).If the symbol has to incorporate both quantitative and qualitative meanings, this is possible by using composite symbols of visual variables, size and color, for example. But what about other combinations? For relief representation, contour lines is a basic method but layer tint is also used. In the latter case, the contour band is tinted by the combination of colour and value. For colour selection, it is necessary to have a design policy the section of which should be emphasized. In Tanaka Kitiro’s method (Tanaka, 1950), the contour band is shaded by lighting from the upper left (Figure 2). The shading uses human intuition to perceive the concave and convex of a relief, which contributes to the understanding of the basic context of spatial structure.If the symbol is nominal or qualitative and to minimize the action of having to refer to the legend, ideogrammatic symbol could be useful instead of abstract ones. But the design of ideogrammatic symbols depends considerably on cultural tradition as well as the surrounding physical environment. Symbols of industrial equipment are rather similar − a wind power plant (Figure 3), for example − but cultural places, such as religious sites, are different in each country. Since there might not be a universal solution, it is desirable at least to know what others do. If we can establish an intermediate language for each symbol, it might be possible to translate instantly between symbols using a symbol dictionary through a system.In visual variables, the principal notion is developed in the form of a matrix composed of six variables − size, value, texture, colour, orientation and shape − and three geometrical characters: point, line, and zone. With this, the characteristics of abstract symbols are described. But if we introduce the notion of scales, composite symbols, and ideogrammatic symbols, elements of context and design need to be considered in order to build a map quickly and for it to be easily understandable.

Crisis Maps—Observed Shortcomings and Recommendations for Improvement

Cartographic communication through crisis maps takes place in a unique environment characterised by the immediate risks of considerable loss and stress. Many such maps are designed by practitioners with limited resources, pressured for time, and who often fail to pay the necessary attention to map graphics. This can reduce map clarity and make orientation to and understanding of essential crisis information difficult. To identify the most frequent shortcomings that may compromise the interpretation of depicted objects, phenomena presented, and actions required, we assessed the map graphics of 106 maps specifically designed for communication and action in crises. The results showed that they were often visually overloaded. Crisis data were not conveyed by appropriate cartographic representations, and due to the inappropriate use of visual variables, the associative and selective properties of cartographic symbols were overlooked, and their ordered and quantitative features ignored. The use of colour was often not adapted to conventional visual language, and colour symbolism was not always taken into account. The cartographic symbols used were often incomprehensible, illegible, ambiguous, and unclassified, and they lacked symbolism and hierarchical organisation. The article aims to address these problems by proposing guidelines which do not require much time or expertise, but which would ensure that cartographically correct crisis maps are well designed. Objects, phenomena or actions specific to crisis management would be indicated using appropriate map graphics and their importance highlighted, so as to make interpretation easier for all participants in a crisis event, and so facilitate crisis communication and response.

Off-Screen Landmarks on Mobile Devices: Levels of Measurement and the Perception of Distance on Resized Icons

While bringing portability and convenience to their users, the small screen size of mobile devices raises the concern that it might impact a user’s acquisition of spatial knowledge. Visualizing information of off-screen objects on mobile device has thus been introduced as a possible way to overcome this problem. Some approaches encode the distance to off-screen objects very well, but they have not considered the identities of objects, which could serve as easily-recognizable landmarks of recognition. Other approaches have addressed the visualization of distant objects’ identities as landmarks, but they have not considered the representation of distance to their actual locations. Following these approaches, this study introduces the use of visual variable size in the design of symbols for off-screen landmarks to translate both information about both direction and distance. To further investigate the efficiency of using these graduated size symbols, we apply ratio and ordinal levels of measurement to assign size to the symbols. Results show, size at the ordinal level leads to higher efficiency in understanding distance to off-screen locations. Both designs, however, yield challenges in participants’ understanding of distance based on the symbol’s size. As the initial step of investigating the use of visual variables in the design of symbols for off-screen landmarks, we suggest more visual variables be considered in follow-up designs to provide a more comprehensive understanding regarding the effectiveness of visualizing off-screen landmarks on mobile devices.

Complexities of designing terrain maps illustrated with horizontal hachures

ABSTRACTDesigning maps involves numerous decisions on the part of the cartographer, while designing terrain maps adds unique complexities. Terrain is often conceptualized as varying in a smooth and continuous manner, leading to data being stored with field-based models, often using raster datasets. The focus of many map design books and other literature, however, is on symbolizing object-based models. Vector layers such as contours and hachures can be derived from grids, but are conceptually abstract and require special consideration for three-dimensional display. We propose a classification scheme for terrain maps based on four principal elements of design: layer tinting, shading, texturing and form lines. We also propose a new method for automating horizontal hachures that illustrates how the latter three elements meet at a critical design juncture where location, orientation, derived attributes and the use of visual variables to symbolize the terrain intersect. Horizontal hachures combine multiple design elements into an innovative methodology, and can also be combined with terrain mapping elements on other design levels.

La generalización en cartografía básica y temática

El conocimiento y explicación de la organización espacial y sus variaciones es inherente a la Geografía y constituye su esencia para la expresión gráfica (cartográfica). La organización espacial puede entenderse como una jerarquía encajonada de sistemas y subsistemas a diferentes escalas; por tanto requiere ser clasificada jerárquicamente y representada cartográficamente como espacios geográficos de diversos tamaños, dando cabida á la generalización cartográfica. Sin embargo, al revisar los materiales cartográficos prbducidos por diversas entidades nacionales es evidente el uso de clasificaciones planas o no jerarquizadas (a un único nivel). Este hecho obstaculiza el proceso de generalización cartográfica y presenta serias dificultades tanto conceptuales como de procedimiento en el momento de cambiar la escala cartográfica. En este trabajo se plantea una conceptualización de generalización cartográfica con base en la teoría jerárquicay la noción de nivel de resolución, y se muestra cómo la vocación aplicada o instrumental de la clasificación jerárquica es la cartográfica, puesto que cada nivel jerárquico necesita una dimensiórí espacial suficiente para expresarse.Definida la base conceptual, se propone un procedimiento de generalización cartográfica basado en un modelo jerárquico escalar, que define los conceptos que se desarrollan en cada nivel de la jerarquía y los rangos escalares en los que se representa cada nivel. Además se muestra el empleo correcto de las variables visuales que reflejan el nivel de la información y la clasificación jerárquica. La propuesta anterior se aplica en seis ejemplos de generalización para cartografia temática, en los cuales la clasificación jerárquica es fundamental para, a partir del nivel de mayor resolución, avanzar hacia niveles jerárquicos superiores que se representan en escalas cada vez menores.

The Distance–Similarity Metaphor in Network-Display Spatializations

Dimensionality reduction algorithms are applied in the field of information visualization to generate low-dimensional, visuo-spatial displays of complex, multivariate databases—spatializations. Most popular dimensionality reduction algorithms project relatedness in data content among entities in an information space (e. g., semantic similarity) onto some form of distance among the entities, such that semantically similar documents are placed closer to one another than less similar ones. In previous studies of point-display spatializations we have shown that people indeed associate metric straight-line inter-point distances with the semantic dissimilarity of documents depicted as points in two-dimensional space. In this paper we investigate the strategies viewers employ when conflicting notions of distance (straight-line metric vs. network metric vs. topological proximity) are jointly shown in a spatialized network display of Reuters news articles depicted as points connected by links. We report empirical results of an experiment where viewers are asked to assess document similarity, depending on various distance types. We also investigate how cartographic symbolization principles (the use of visual variables, such as size, color hue, and value) influence similarity judgments. These findings provide rare empirical evidence for generally accepted design practices within the cartographic community (e. g., the effects of visual variables). In addition, empirical results from this and related studies can be used to develop design guidelines for constructing cognitively adequate spatializations for knowledge discovery in very large databases. We conclude by presenting design guidelines for network spatializations within the context of cartographic practice and theory.