Jolanta Korycka-Skorupa

Choropleth maps and diagram maps in atlas of cartographic presentation methods

Abstract The online Atlas kartograficznych metod prezentacji [Atlas of cartographic presentation methods, hereinafter the Atlas] is a research project being carried out at the Department of Cartography of the University of Warsaw. The aim of the project is to systematize knowledge about the use of cartographic presentation methods. This study discusses selected issues related to two of the five presentation methods analysed in the project, viz. the choropleth map and the diagram map. A rational application of two quite commonly-used presentation methods leads to a number of problems. These problems are most easily visible during attempts to program its implementation in the web-based Atlas and are largely due to the difficulties with drawing a clear boundary between what is a good and a bad map. For this reason, the system operator’s skill and eye for the graphics of semi-automated visualisation seem to be of key importance.

The place of the “quantitative signature symbols” in the classification of the cartographic presentation methods

Abstract The authors of the article pay their attention to the lack of a generally accepted classification of the cartographic presentation methods. The classification, which was described in the Ratajski’s handbook (1989) in the mostly extensive way, is commonly used in the Polish literature. According to the authors, it would be appropriate to modify one of the types of symbols (quantitative ones) as an independent method of data presentation at the quantitative level, in addition to the method of diagram, choropleth, dot method and isoline one.

A thematic cartographic visualization of a small region, based on the example of the Mrozy Commune

Abstract The purpose of this study was to produce a multifaceted presentation of a small region. It was realised based on two aims: the collection of spatial and statistical data, and the analysis of the data from the perspective of physical and socio-economic geography. Mrozy commune (Polish – gmina Mrozy) is located in the eastern part of the Masovian voivodeship, in the county of Minsk (Polish – powiat miński). The initial stage involved obtaining data from various sources. The second phase concerned the assessment of the data’s quality. Next, appropriate visualization methods were selected; the authors used cartographic techniques for data presentation, resulting in a set of thematic maps at a scale of 1:100,000. The final part of this research concerned the evaluation of the results and the verification and correction of errors. The accuracy of the maps for this small area has been checked and the maps will be made available to the local authorities.

Cartographic presentation – from simple to complex map

Abstract Nowadays a lot of people are trying to make maps, and especially digital maps. A wide range of computer tools and high graphic capabilities have together made maps increasingly popular and seemingly easy to prepare for any person who can use a computer. It seems necessary to verify the bases of the cartographic presentation methods. There is a need for a new, formalized view of the method as a sequence of steps from data collection, to correct presentation, to map. Two terms related to cartographic presentation should be distinguished in this article: “methods” and “forms.” A method is understood as the process by which data is transformed into a presentation. A form is understood as the end result of this process, i.e. the resulting graphical image or map. In the article five types of cartographic presentation are indicated. In the successive types, one can observe an increasing degree of complexity of cartographic presentation.

Visual clutter reduction in zoomable proportional point symbol maps

ABSTRACT Proportional point symbols are commonly used in map displays. However, when such displays are zoomed out, the available map space shrinks and consequently symbols overlap and the display suffers from visual clutter. Therefore, solutions are needed to reduce visual clutter in zoomable map displays that contain proportional point symbols. The authors add to the body of knowledge through the investigation of the performance of three solutions: aggregation of unit areas, the displacement of overlapping symbols, and modified symbolization; four variations of modified symbolization are examined in detail. The original study begins with a consideration of the strengths and weaknesses of the solutions, with an emphasis on information loss. Thereafter, user sessions with 165 participants are arranged to gain empirical evidence of the performance of the solutions. The results reveal that although participants zoom out the map to zoom levels that implement visual clutter reduction techniques, they tend to zoom in the map and pan it to examine specific areas. Moreover, they willingly use the map with aggregated unit areas in cases when the solution facilitates task accomplishment. A certain amount of skepticism attaches to the solution that displaces overlapping symbols.

The beginnings of the choropleth presentation

Abstract The discovery in the cartographic collections of the Faculty of Geography and Regional Studies at the University of Warsaw of an original map by Charles Dupin – the first choropleth map – provided an opportunity to conduct a closer methodological analysis of the map and to investigate the subsequent development of this presentation method during the first half of 19th century. From relatively early on, the accepted principle was for choropleth map presentations to use statistical data still imprecisely referred to as relative, as well as using a distribution series as a method of generalizing data.

The teaching of cartography and topography in the Polish primary school

Abstract The authors present a content analysis of the selected textbooks for teaching the natural science in the Polish primary school in the scope of cartography and topography. Two series of textbooks edited by the Nowa Era publishing house and approved by the Ministry of National Education are used by the authors. The main aim of this analysis is to determine whether the textbooks meet the requirements of the new core curriculum. The psychological aspects that may cause the difficulties in learning the natural science for students of grades 4 through 6 of the primary school are also discussed. The contents of textbooks are absorbed by the students in varying degrees. It is important, therefore, to take into account the psychological aspects of the students’ learning process and draw attention to the difficulties that may arise in the course of grade 4–6 instruction. Among them there are, inter alia, the difficulties in using a map scale, some problems with imagining the actual distances and areas, a height above the sea level and the relative heights, as well as the issues related to the students’ abilities to read a drawing of contour lines. In the process of natural science education in the primary school, it is very important to develop the children’s abstract thinking, which causes the stimulation of their spatial imagination. The various types of teaching aids, which can be helpful for the both groups, as for the teachers, so for the students, are discussed in this article. These are the atlases, models, interactive teaching aids, books and educational games. The analysis introduced in this article allows for a critical evaluation of the textbooks for primary school from the point of view of their content complacencies on cartography and topography with the new core curriculum. Teaching the bases of cartography and topography from an early age is very important, but developing the ability to use a map requires the continuous exercises. Working with a map helps to develop not only the practical skills, but also the students’ attitudes having a positive impact on the development of such qualities as conscientiousness, accuracy and patience; it also has an invaluable impact on the students’ spatial imagination.

An evaluation of GIS tools for generating area cartograms

Abstract The purpose of this article is to report a study aimed at systematic assessment of the functionality of commercially available software for the automatic generation of area cartograms. The issue of the wide choice of algorithms developed over the years for generating various types of surfaces has also been raised. Cartograms (called also anamorphic maps) are constructed by changing the surface area of each spatial unit in step with the corresponding value of the mapped thematic variable (area cartogram) or changing accordingly the distance between the preselected focal point and other points on the map (distance cartogram). Depending on the shape of mapping units, the following three types of area cartograms can be distinguished: proportional symbol cartograms were the original shapes of mapping units have been replaced with simple geometric shapes such as squares, rectangles or circles (for example, Dorling Circle Cartograms, square cartogram); continuous regular cartograms where the shapes of areal units on the map resemble the actual shapes of the mapped units but their boundaries have been geometrized to consist of perpendicular sections; continuous irregular cartograms where the shapes of areal units on the map resemble the actual shapes of the mapped units but unit boundaries are not straight lines. Cartograms can also be constructed to preserve spatial contiguity (continuous cartograms) or not (noncontinuous cartograms), with the latter often preserving the underlying neighborhood relationships to some degree. While constructing area cartogram, one needs to decide first the type of a surface to be developed, and therefore, the algorithm to be applied. The next step in map construction is the choice of software, where tool selection depends often on the predetermined type of the cartogram. The study surveyed five programs for the construction of area cartograms – all available free of charge. Each of those software tools was used to generate area cartograms portraying data from the 2010 presidential election in Poland. Two groups of area cartograms where generated for the purpose of this study: maps of the entire Poland by voivodships, showing the number of valid votes cast for the two presidential candidates in each voivodship, and maps of the Mazowieckie voivodship by county, portraying the number of valid votes cast for the individual candidates in each county. The subsequent in-depth assessment of surveyed programs took into account eleven criteria including the number of cartogram types that might be developed using each program, availability of tools for the proper legend construction and display, possibility of supplementing the cartogram with complementary choropleth maps, the option for inserting map labels, the type of spatial data that can be used in the software (reference to points, lines, polygons) and so on. The study has demonstrated that the tool included in the ArcGIS (Cartogram Utility for ArcGIS) best met the survey criteria scoring 9 points. The application Scape Toad placed second (7.5 pts.), while MapViewer 7 came third (6.25 pts.). When generating cartograms in the available GIS programs, one should also pay attention to the visual qualities of the generated maps, and in particular, to the resemblance of shapes of spatial units on the map to the their actual geographic boundaries. Since the shape outlines obtained on the map vary depending on the underlying geodetic reference system, the best coordinate system for the mapped area should be selected. However, if such system cannot be used within a given cartogram generating tool, then the obtained cartogram should be exported and refined with some general software package for graphic editing.

Effectiveness of cartographic presentation methods applied within small-scale thematic maps in the press and on the Internet

Abstract The author discuss effectiveness of cartographic presentations. The article includes opinions of cartographers regarding effectiveness, readability and efficiency of a map. It reminds the principles of map graphic design in order to verify them using examples of small-scale thematic maps. The following questions have been asked: Is the map effective? Why is the map effective? How do cartographic presentation methods affect effectiveness of the cartographic message? What else can influence effectiveness of a map? Each graphic presentation should be effective, as its purpose is to complete written word, draw the recipients’ attention, make text more readable, expose the most important information. Such a significant role of graphics results in the fact that graphic presentations (maps, diagrams) require proper preparation. Users need to have a chance to understand the graphics language in order to draw correct conclusions about the presented phenomenon. Graphics should demonstrate the most important elements, some tendencies, and directions of changes. It should generalize and present a given subject from a slightly different perspective. There are numerous examples of well-edited and poorly edited small-scale thematic maps. They include maps, which are impossible to interpret correctly. They are burdened with methodological defects and they cannot fulfill their task. Cartography practice indicates that the principles related to graphic design of cartographic presentation are frequently omitted during the process of developing small-scale thematic maps used – among others – in the press and on the Internet. The purpose of such presentations is to quickly interpret them. On such maps editors’ problems with the selection of an appropriate symbol and graphic variable (fig. 1A, 9B) are visible. Sometimes they use symbols which are not sufficiently distinguishable nor demonstrative (fig. 11), it does not increase their readability. Sometime authors try too hard to reflect presented phenomenon and therefore the map becomes more difficult to interpret (fig. 4A,B). The lack of graphic sense resulting in the lack of graphic balance and aesthetics constitutes a weak point of numerous cartographic presentations (fig. 13). Effectiveness of cartographic presentations consists of knowledge and skills of the map editor, as well as the recipients’ perception capabilities and their readiness to read and interpret maps. The qualifications of the map editor should include methodological qualifications supported by the knowledge of the principles for cartographic symbol design, as well as relevant technical qualifications, which allow to properly use the tools to edit a map. Maps facilitate the understanding of texts they accompany and they present relationships between phenomenon better than texts, appealing to the senses.