Alan M. MacEachren (born 1952) is an American geographer, Professor of Geography and Director, GeoVISTA Center, Department of Geography, The Pennsylvania State University. He has played a leading role nationally and internationally in defining a research agenda for human-centered geospatial visualization and in building cross-disciplinary links to related efforts in scientific and information visualization and in statistics.
Alan MacEachren received a B.A. in Geography in 1974 at the Ohio University, an M.A. in Geography in 1976 from the University of Kansas and a Ph.D. in 1979 from University of Kansas, also in Geography.
From 1979 to 1983 he was Assistant Professor of Geography at the Virginia Polytechnic Institute and State University and Director of the Department of Geography Cartography Laboratory. From 1980 to 1983 he was Director of the Department of Geography Spatial Analysis Laboratory, Virginia Polytechnic Institute and State University. In 1983 he became Assistant Professor of Geography at the University of Colorado-Boulder and in 1985 switched to Associate Professor of Geography and Director of the Deasy GeoGraphics Laboratory at the Penn State University, where he worked until 1992. From 1992 he was Professor of Geography, and since 1998 Director, GeoVISTA Center, Department of Geography, Penn State University. In Fall 2007 he was Visiting Professor, Department of Computer Science, Stanford University, and since 2007 also Affiliate Professor of Information Sciences and Technology, Penn State University.
Recent Awards for Alan MacEachren in 2004-2007 include the E. Willard and Ruby S. Miller Professor of Geography, College of Earth and Mineral Science, Penn State University. He became an Honorary Fellow of the International Cartographic Association in 2005: the sixth Fellow from the U.S. since 1974. In 2004 he was also recognized for Exceptional Scholarly Contributions to the Practice of Cartography, Canadian Cartographic Association.
His research interests are Geovisualization; Exploratory Spatiotemporal Data Analysis; Geocollaboration (group work with geoinformation); Cartography; Spatial and Environmental Cognition; Applications in: Health, Environment, and Decision-making. His most recent research focusses on integration of geographic visualization with other knowledge construction methods, natural interfaces to GIS, GeoVirtual environments, and geocollaboration (design and use of technologies to enable groups to work productively with geospatial information). 
Building from a background in cartography and environmental cognition, his work during the 1990s focused on a range of issues associated with geographic representation and geovisualization. Within these domains, a long standing interest has been the interaction between formalized visual and digital representations inherent in maps and geographic information systems and human mental representation of space and space-time.
In "How Maps Work: Representation, Visualization and Design" he develops a cognitive-semiotic theoretical perspective from which to address these and related issues. Much of his work deals with dynamic forms of representation. These include exploratory spatial data analysis tools and map animation for understanding geographic processes.
Application areas focused on in his geovisualization research have included epidemiological analysis, earth science education, implications of global environmental change, and uncertainty in health and environmental data and in meteorological and climatological model results.
Visualizing Structure in Scientific Discourse
In "Visualization for constructing and sharing geo-scientific concepts " (2004) MacEachren describes his initial work toward dynamic, visual methods and tools that support the construction, communication, revision, and application of scientific knowledge. Specifically, he focuses on tools to capture and explore the concepts that underlie collaborative science activities, with examples drawn from the domain of human–environment interaction.
He presents coordinating bottom-up and top-down approaches to analysis, with eight steps:
- Concepts to be used in an analysis are extracted from the ontology and held in an experimental notepad.
- Design for the experiment is constructed by using the Studio visual programming utility.
- The data are analyzed for emergent structures and relationships that can be utilized and for errors and unhelpful attributes that possibly should be removed.
- The experiment produces a result set of categories, held intentionally as pieces of a classifier model and extensionally as a map or dataset.
- Problems with the result can cause the experimental design to be changed.
- Problems with the result might lead to a reexploration of the data.
- Problems with the result might cause the user to modify the concepts being utilized.
- Modified concepts can be inserted into the ontology, leading to a modified ontology.
He has designed and is currently implementing and testing a suite of tools, developed in GeoVISTA Studio (www. geovistastudio.psu.edu; ref. 55) that connect the top-down processes of (i) defining and browsing concepts ontologically, (ii) selecting specific concepts to use in an analysis exercise, and (iii) operationalizing the concepts with classifiers with the bottom-up processes of (iv) data exploration to help formulate concepts from emergent structures in the data and (v) modification of the concepts, classifiers, or data used as a result of poor categories being produced from data.
- Animated mapping
- Figure-ground in map design
- History of cartography
- Spatial analysis
- Theresa-Marie Rhyne
Alan MacEachren has written several books and articles. A selection:
- 1994. Visualization in modern cartography. With D.R. Fraser (ed.). Taylor.
- 1995. How maps work : representation, visualization, and design How maps work : representation,
- 1994. Some truth with maps : a primer on symbolization and design
- 1997. Rediscovering Geography: New Relevance for the New Century. With 13 other authors. Washington, D. C.: National Academy of Science Press.
- 2005. Exploring Geovisualization. With J. Dykes and M.J. Kraak. International Cartographic Association.
- 2005. Illuminating the Path: The Research and Development Agenda for Visual Analytics. With 25 other authors. Pacific Northwest National Laboratory and Department of Homeland Security.
- MacEachren, Alan at www.infovis-wiki.net.
- Alan MacEachren Background. Retrieved 28 June 2008.
- Alan M. MacEachren, Mark Gahegan, and William Pike (2004). "Visalization for constructing and sharing geo-scientific concepts". In: PNAS April 6, 2004 vol. 101.
- Alan M. MacEachren List of publications from the DBLP Bibliography Server.
- Alan M. MacEachren. Director, GeoVISTA Center. The Pennsylvania State University.
- List of Influences: Alan MacEachren by Robert Kosara, 2007-04-03.