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After demonstrating that rainbow colors are still commonly used in scientific publications, we comparatively evaluate the rainbow and sequential color schemes on choropleth and isarithmic maps in an empirical user study with 544 participants to examine if a) people intuitively associate order for the colors in these schemes, b) they can successfully conduct perceptual and semantic map reading and recall tasks with quantitative data where order may have implicit or explicit importance. We find that there is little to no agreement in ordering of rainbow colors while sequential colors are indeed intuitively ordered by the participants with a strong dark is more bias. Sequential colors facilitate most quantitative map reading tasks better than the rainbow colors, whereas rainbow colors competitively facilitate extracting specific values from a map, and may support hue recall better than sequential. We thus contribute to dark- vs. light is more bias debate, and demonstrate why and when rainbow colors may impair performance, and add further nuance to our understanding of this highly popular, yet highly criticized color scheme.

Thoughtful consideration of the enumeration unit size in choropleth map design is important to ensure the correct communication of spatial information. However, the enumeration unit size and its influence on pattern conveying in choropleth maps have not yet been the subject of in-depth empirical studies. This research aims to address this gap. We focused on the issue concerning whether the ability to recognize spatial patterns on an Equal Area Unit Map is related to the hexagonal enumeration unit size, defined by the number of pixels. The aim is to indicate the range of the enumeration unit sizes, namely, at what point the upper and lower borders of the range where the spatial patterns start, and where the end is visible and recognizable by users. To address this problem, we conducted an empirical study with 488 users. The results show that the enumeration unit size has an impact on the users’ spatial pattern recognition abilities. Choropleth maps with enumeration unit sizes of 26, 52, and 104 pixels were, in the majority, indicated by participants as those most suitable for indicating spatial patterns. This was in contrast to choropleth maps with enumeration unit sizes of 1664 and 3328 pixels, which users indicated as not being useful. However, there were some exceptions to this general finding. Thus, determining the optimal enumeration unit size is a challenging task, and requires further insightful investigations.

It is acknowledged that various types of thematic maps emphasize different aspects of mapped phenomena and thus support different map users’ tasks. To provide empirical evidence, a user study with 366 participants was carried out comparing three map types showing the same input data. The aim of the study is to compare the effect of using choropleth, graduated symbols, and isoline maps to solve basic map user tasks. Three metrics were examined: two performance metrics (answer accuracy and time) and one subjective metric (difficulty). The results showed that the performance metrics differed between the analyzed map types, and better performances were recorded using the choropleth map. It was also proven that map users find the most commonly applied type of the map, choropleth map, as the easiest. In addition, the subjective metric matched the performance metrics. We conclude with the statement that the choropleth map can be a sufficient solution for solving various tasks. However, it should be remembered that making this type of map correctly may seem easy, but it is not. Moreover, we believe that the richness of thematic cartography should not be abandoned, and work should not be limited to one favorable map type only.

As the development of small-scale thematic cartography continues, there is a growing interest in simple graphic solutions, e.g., in the form of numerical values presented on maps to replace or complement well-established quantitative cartographic methods of presentation. Numbers on maps are used as an independent form of data presentation or function as a supplement to the cartographic presentation, becoming a legend placed directly on the map. Despite the frequent use of numbers on maps, this relatively simple form of presentation has not been extensively empirically evaluated. This article presents the results of an empirical study aimed at comparing the usability of numbers on maps for the presentation of quantitative information to frequently used proportional symbols, for simple map-reading tasks. The study showed that the use of numbers on single-variable and two-variable maps results in a greater number of correct answers and also often an improved response time compared to the use of proportional symbols. Interestingly, the introduction of different sizes of numbers did not significantly affect their usability. Thus, it has been proven that&mdash, for some tasks&mdash, map users accept this bare-bones version of data presentation, often demonstrating a higher level of preference for it than for proportional symbols.

Maps are frequently combined with data displays in the form of coordinated and multiple views (CMV). Although CMV are valuable geovisualization tools, novice users may find them complex and thus require explanation. However, no tutorial guidelines have been developed that indicate what is helpful in understanding CMV geovisualization tools. We therefore conducted a study on the learnability of a CMV tool, informed with eye-tracking data, talk-aloud and interaction logs. We have investigated how untrained users work with a CMV geovisualization tool. The study revealed that: (1) despite their initial confusion, users found the tested tool pleasant to play with while getting to grips with how dynamic brushing works, (2) when examining the tool’s interface, participants mainly looked freely at explanatory elements, such as labels and the legend, but they explored interactive techniques only to a limited degree. We conclude with tips about tutorial design and layout design for CMV tools. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.

Colour is one of the most useful variables to be applied in map design for information visualization. The choice of colour scheme affects the visual appearance of the map, its aesthetics, and how pleasant it appears. Consequently, it may, potentially, impact data perception, which has been proved by various authors (e.g. Brewer et al. 1997, Brychtova and Çöltekin 2015). There are established guidelines regarding colour use in cartography, for example, in textbooks. It is a well-established rule that when presenting quantitative data, the various values of the mapped data should be mainly represented by varying the colour value. But a growing frequency in colour use that contradicts the rules of cartographic visualization has been observed. The case is particularly true of the rainbow colour schemes (Figure 1.), which are commonly applied in geovisualisation practices in thematic maps; in the past, mainly on isoline maps; and currently, also on choropleth maps. The schemes involve the use of varying hues for presenting quantitative data, typically via a gradation based on the electromagnetic spectrum, instead of the practice recommended in cartography of varying colour value. The scale is interpolated through the saturated, spectrally ordered hues: blue, cyan, green, yellow, and red. The result is a vivid, fully saturated colour map that looks like a rainbow. This colour scheme is commonly considered to be a very poor way of representing data due to several problems. The disadvantages most often raised are as follows: (1) it is not perceptually ordered and there is no logical ordering (Monmonier 1991), which means there is no innate sense of higher or lower values; (2) it introduces sharp transitions between hues as the perceptual changes in the rainbow colours are not uniform (Moreland 2016), and which may be perceived as being a considerable transition in the mapped data; and (3) the middle values may be interpreted as extreme values since yellow has a highlighting effect, being perceived as brighter than the other colours. The rainbow colour scheme is applied mainly in visualizing the quantitative data of various themes, both natural (weather maps, elevation) and socio-economic. The colour scheme can be found on on isoline maps; and currently, also on choropleth maps. Using rainbow colours for mapping natural phenomena such as temperature or elevation seems to be understandable, as they are presented using isolines. The use of spectral progression for relief maps is a convention of long standing; it is now well known through its regular appearance on school maps and atlas maps for the general public. However, applying this colour code to social data mapping using choropleth maps may not always be intuitive. Choropleth maps do not show the order of the colour on the face of the map, in contrast to isoline maps where colours are always in the same order on the map. The issue of the incorrect use of the rainbow colour scheme in cartographic visualization was raised two decades ago. What is important is that Brewer (1997) raised doubts concerning the warnings that spectral hues were not ordered; and considered that this idea may no longer be valid due to users’ continuous exposure to spectral graphics. There is a ‘likelihood that the public is learning this code, through its use on most scientific visualizations that enter the public sphere.’ (Brewer 1997: 217). Nowadays, this issue is still important with even more frequent use of spectral colour schemes in practice, often for non-diverging, sequential data. This makes the need for validating current practices more vital in order to verify if the commonly applied rainbow colour schemes can actually represent quantitative, non-diverging data on maps as effectively as the traditionally recommended sequential colour schemes. Further research is thus needed to validate the current common practices of using rainbow colours, and to establish evidence-based guidelines for color-coding on thematic maps. The aim of the study is to empirically evaluate the usability of the rainbow colour scheme for thematic maps. For this investigation choropleth maps presenting social data will be selected. Over 200 participants (high school students) will take part in the study and will be asked to solve different tasks using the presented maps. The participants will be dived into two groups, with each group solving the same tasks but using choropleth maps with differently designed colour scales: (1) a rainbow colour scheme, and (2) a colour scheme considered to be correct for non-diverging data, i.e., a sequential, value-varied colour scale. The study applies usability performance metrics, expressed as effectiveness (response correctness), efficiency (answer time), and preferences (users opinions). The participants will be given various tasks, ranging from reading quantities, to noting distributions and extracting patterns. Participants will also be asked to recall the studied maps. The tasks partially refer to the questions asked by Mersey (1990) in an in-depth evaluation of various colour schemes (including spectral). We thus want to compare this study’s results with those collected over 30 years ago, and verify the assumption posed by Brewer (1997), that is, if nowadays, frequent exposure to rainbow maps results in improving usability of the rainbow colour scheme for maps, in a similar way – or to some extent – to the use of spectral colours for elevation maps. By conducting this empirical investigation we hope to contribute to an increased understanding of how thematic geovisualisations should be designed in order to support users effectively. We also want to empirically verify the rules that have been established in cartographical theory, but which are often violated in practise. As Brewer (1997) noted, cartographers cannot stop people from selecting spectral schemes, but we can try to assess the consequences of applying such colour schemes to thematic maps.

Planar deformation features (PDFs) in quartz are the most important diagnostic features that allow the unambiguous identification of impact structures on Earth. In order to confirm that these features (that are characterized by planar character and form along specific crystallographic planes) are indeed PDFs, they need to be properly investigated and indexed. Following universal-stage measurements, the process of indexing is usually performed manually, using a Wulff stereonet and following a strict procedure, which is time consuming and error prone. In this article, we present WIP, a new Web-based program for indexing planar deformation features in quartz. The correctness of our program is shown by its application to measurements that had previously been indexed manually. The observed minor differences, especially in the absolute frequency percentage of PDFs, are negligible and not significant enough to influence the estimation of shock pressure that could be calculated from the indexed results. Usability of this program is shown using the spatial relationships between a statistically significant number of 278 quartz grains with 409 sets of PDFs analyzed within the area (~35 mm2) of a single thin section of a meta-greywacke from the Bosumtwi impact structure. Our program is not only more accurate and faster than the manual (graphical) method but also removes the human error from the plotting process and allows control of several parameters, such as the value of estimated measurement error used in the indexing calculation or method of aggregated error handling. The program also provides information about the angles between the planes of the measured PDF sets present in a grain, which allows determination of the angles between (for example) indexed {} and {} sets.

We discuss the process of designing, using, and evaluating maps during planetary analog missions. We present the evolution of the mapping strategy within the Austrian Space Forum (OeWF) that took place between 2006 and 2018 in response to increasing complexity and fidelity level of the field missions. We also provide suggestions for the efficient preparation of maps to be used during future planetary analog missions.

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 legend is a critical tool in reading and interpreting a thematic map. The goal of the study reported here is to understand how the legend works as a map is read. The methodology combined usability performance metrics with the thinking aloud method. Subjects were asked to perform two sets of tasks using two thematic maps with different legend layouts. While latency and accuracy of answers for the first set of tasks did not differ significantly between users of the different layouts, users clearly preferred legends that were simple or familiar. The thinking aloud protocols from the second part of the study revealed different patterns of legend comprehension for each legend design. In addition, the study identified four problem-solving strategies that were adopted by the subjects. Finally, some principles for designing legends were developed from the results of the study.

Geographic visualization tools with coordinated and multiple views (CMV) typically provide sets of visualization methods. Such configuration gives users the possibility of investigating data in various visual contexts; however, it can be confusing due to the multiplicity of visual components and interactive functions. We addressed this challenge and conducted an empirical study on how a CMV tool, consisting of a map, a parallel coordinate plot (PCP), and a table, is used to acquire information. We combined a task-based approach with eye-tracking and usability metrics since these methods provide comprehensive insights into users’ behaviour. Our empirical study revealed that the freedom to choose visualization components is appreciated by users. The individuals worked with all the available visualization methods and they often used more than one visualization method when executing tasks. Different views were used in different ways by various individuals, but in a similarly effective way. Even PCP, which is claimed to be problematic, was found to be a handy way of exploring data when accompanied by interactive functions. © 2016 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/),which permits non-commercial re-use, distribution, and reproduction in anymedium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.

MARS2013 was an integrated Mars analog field simulation in eastern Morocco performed by the Austrian Space Forum between February 1 and 28, 2013. The purpose of this paper is to discuss the system of data processing and utilization adopted by the Remote Science Support (RSS) team during this mission. The RSS team procedures were designed to optimize operational efficiency of the Flightplan, field crew, and RSS teams during a long-term analog mission with an introduced 10 min time delay in communication between "Mars" and Earth. The RSS workflow was centered on a single-file, easy-to-use, spatially referenced database that included all the basic information about the conditions at the site of study, as well as all previous and planned activities. This database was prepared in Google Earth software. The lessons learned from MARS2013 RSS team operations are as follows: (1) using a spatially referenced database is an efficient way of data processing and data utilization in a long-term analog mission with a large amount of data to be handled, (2) mission planning based on iterations can be efficiently supported by preparing suitability maps, (3) the process of designing cartographical products should start early in the planning stages of a mission and involve representatives of all teams, (4) all team members should be trained in usage of cartographical products, (5) technical problems (e.g., usage of a geological map while wearing a space suit) should be taken into account when planning a work flow for geological exploration, (6) a system that helps the astronauts to efficiently orient themselves in the field should be designed as part of future analog studies.

Quite a few examples in the cartographic and information visualisation literature suggest that multi-component animated maps may be appropriate for examining complex spatio-temporal phenomena. Such space–time visualisations typically consist of multiple dynamic map or data windows, linked by means of interactive tools. Little empirical evidence exists, however, providing support of the potential advantages of such complex visual space–time displays. This research aimed at filling this gap. An empirical study was carried out to obtain insight on how multi-component animated maps are used to explore dynamic spatio-temporal phenomena. We examined which particular components attract users’ attention and in what sequence, and whether display effectiveness can be characterized by users’ viewing behaviours. Based on behavioural data collected with the eye-tracking method, we find that component size, and employed dynamic variables attracted users’ attention most. We are also able to identify visual behaviour patterns that result in performance differences between participants, using multi-component animated map. Finally, we highlight component layout design issues that should be further examined empirically, in order to reduce potential split attention effects.