Mark Harrower

The integration of geographic visualization with knowledge discovery in databases and geocomputation

This paper details the research agenda of the International Cartographic Association Commission on Visualization: Working Group on Database-Visualization Links. The paper stresses the need for the closer integration of three largely disparate technologies: geographic visualization, knowledge discovery in databases, and geocomputation. The introduction explains the meaning behind these terms, the ethos behind their practice, and their connections within the broad realm of knowledge construction activities. The state of the art is then described for different approaches to knowledge construction, concentrating where possible on visual and geographically oriented methods. From these sections, a research agenda is synthesized in the form of three sets of research questions addressing: (1) visual approaches to data mining; (2) visual support for knowledge construction and geocomputation; and (3) databases and data models that must be satisfied to make visually-led knowledge construction a reality in the geographic realm. Conclusions relate this agenda to issues of (1) data, (2) geographic knowledge, and (3) the visualization environment and pose significant challenges to the way we currently represent geographic information and knowledge within computational systems.

The Cognitive Limits of Animated Maps

When it comes to designing animated maps, the bottleneck is no longer the hardware, the software, or the data – it is the limited visual and cognitive processing capabilities of the map reader. Only sporadic progress has been made within GIScience in answering even the most basic questions: Under what conditions and for what kinds of map-reading tasks are animated maps effective, and how can their effectiveness be increased? Fortunately, over the past 20 years cognitive researchers in psychology and education have created a comprehensive set of theories that explain how people look at and learn from dynamic images, under what conditions these images work or fail, and why. Moreover, numerous controlled experiments, often designed to replicate and build upon previous studies, have validated these theories (something that is rare in cartography). This article presents a synthesis of this research and shows how it (1) directly informs mapping practices, (2) explains important cognitive differences between sta...

Tips for Designing Effective Animated Maps

For mapmakers, animating maps presents an amplified cartographic challenge. Because animated maps are difficult and expensive to make—even with today’s powerful software and computers—a designer will want to be reasonably confident that their efforts will pay off with a map that is both attractive and informative. There is no shortage of poorly conceived and clumsily executed maps with animated content to be found these days, and many such examples seem made for no other reason than “they look cool” (Campbell and Egbert 1990). In the spirit of Edward Tufte, it is always worth asking why do I need to animate these data? Does the animation lend something to the representation that would be difficult or impossible to convey in static form? If the answer is yes, than the added expense and time of creating an animated map may well be justified. Cartographers who want to use animation to make a better map must know the strengths and limitations of animation as a tool, and how map-readers are likely to be impacted by animation. This article presents suggestions for creating effective animated maps derived from my experiences both as a user and as a creator of animated maps, as well as insights from formal user-testing over the past few years. Below, I offer some solutions to the four major challenges identified by Morrison (2000) with watching and learning from animated graphics: disappearance, attention, confidence, and complexity.

A Look at the History and Future of Animated Maps

Compared to static maps, animated maps have always been difficult to make, distribute, and access. The PC and Internet revolutions have greatly improved opportunities for animated maps, and a new era of on-demand animated maps is emerging. In this article, a three-tier historical framework is presented that identifies the key conceptual and technological developments of animated cartography related to the means of production, methods of distribution, and modes of use. Such a historical overview is largely missing from the cartographic literature and helps to situate current developments and issues within a broader social and technological context. The future development and direction of animated maps can be informed by identifying the pivotal ideas and technologies of the last 60 years. It is worth revisiting foundational — but technologically impractical — ideas for animated maps developed by pioneering cartographers in the pre-digital and pre-Web era. This research also includes a look at important rema...

MapShaper.org: a map generalization Web service

Map is a macromedia flash-based WYSIWYG map generalization Web service for real-time generalizing and editing of vector map data. Requiring only a Web browser with the flash plug-in, it offers line and shape simplification and smoothing. Users can upload map files, perform generalization operations, and export and download their work

Addressing Map Interface Usability: Learning from the Lakeshore Nature Preserve Interactive Map

These are exciting days for cartography, as emerging technologies have greatly expanded the possibilities of online, interactive maps. These developments, however, now require cartographers to think about issues that only a few years ago fell solely in the domains of human-computer interaction (HCI) and web design. Further, given how fast these changes have occurred, there are few tried-and-true guidelines for building digital maps. This paper reports on the design, development, and evaluation of the University of Wisconsin-Madison Lakeshore Nature Preserve Interactive Map (www.lakeshorepreserve.wisc.edu) and outlines many of the insights gleaned from this process. The purpose of this article is to strengthen the important bridge between cartography and usability evaluation (i.e., how we study the way in which users interact with their maps and how we measure the success of those interactions) so that the efforts of a team of developers and stakeholders can be coordinated in a way that ensures the map works equally well for all potential end users. We outline the relative merits of two broad categories of evaluation techniques, arguing that there is no single, correct evaluation technique appropriate for all evaluation scenarios, and then detail the specific strategy adopted for evaluation of the Lakeshore Nature Preserve Interactive Map. We conclude by offering four design guidelines for online, interactive maps revealed during the evaluation of the Lakeshore Nature Preserve Interactive Map: two positive strategies we recommend for consideration when designing map interfaces (inclusion of cascading interface complexity and provision of map browsing flexibility) and two pitfalls we caution to avoid (minimalist design of interface widgets and employment of a lorem ipsum map during development).

Visualizing Change: Using Cartographic Animation to Explore Remotely-Sensed Data

This research describes a geovisualization tool that is designed to facilitate exploration of satellite time-series data. Current change-detection techniques are insufficient for the task of representing the complex behaviors and motions of geographic processes because they emphasize the outcomes of change rather than depict the process of change itself. Cartographic animation of satellite data is proposed as a means of visually summarizing the complex behaviors of geographic entities. Animation provides a means for better understanding the complexity of geographic change because it can represent both the state of a geographic system at a given time (i.e. its space-time structure) and the behavior of that system over time (i.e. trends). However, a simple animation of satellite time-series data is often insufficient for this task because it overwhelms the viewer with irrelevant detail or presents data at an inappropriate temporal and spatial resolution. To solve this problem, dynamic temporal and spatial aggregation tools are implemented with the geovisualization system to allow analysts to change the resolution of their data on the fly. These tools provide (1) a means of detecting structures or trends that may be exhibited only at certain scales and (2) a method for smoothing or filtering unwanted noise from the satellite data. This research is grounded in a delineation of the nature of change, and proposes a framework of four kinds of geographic change: location, size/extent, attribute and existence. Each of these kinds of change may be continuous (a process) or discrete (an event).

INTRODUCTION Critical Interventions and Lingering Concerns: Critical Cartography/GISci, Social Theory, and Alternative Possible Futures

Welcome to this special issue on Critical Cartographies and GIScience. The call for papers for this issue emphasized three major themes. First, we encouraged authors to focus on socio-political relations inscribed in mapping products and practice, including exploration of the potential for increased democratization of mapping technologies. Second, given the rapidity and intensity of technological innovation and change in the last few years, we were interested in papers that considered the particularities of this current moment with respect to cartographic and digital technology and diffusion, including how these changes force

Depicting classification uncertainty using perception-based color models

Fuzzy classification typically assigns a location or an area to a category with some estimated degree of uncertainty. There are strong incentives for depicting uncertainty along with category, and numerous authors have recommended that this be done using progressive desaturation of the entitys color with increasing uncertainty. This article shows that such recommendations cannot be naively applied using color models widely used in computer graphics because colors equally ‘saturated’ do not appear equally certain. We demonstrate that models based on color perception are preferred, particularly if one wishes to compare uncertainties across classes. We discuss geometrical complications arising with perceptual models that are not present with models closely tied to hardware. An algorithm for selecting colors is presented and illustrated using the model.

The Role of Color Saturation in Maps for Children

Bright, saturated colors are very common on maps for children, especially maps in grade-school textbooks. This is despite the tendency of professional cartographers to use highly saturated colors sparingly in much of their work. This research seeks to determine if highly saturated colors are necessary for children to understand a map’s content and if children prefer highly saturated colors. Two hundred forty two fourth and fifth grade students were tested for both performance and preference on land use and time flow maps. Saturation’s effect on performance appeared to be largely negligible, however the students, both male and female, strongly preferred the maps that were highly saturated.