Stephen M. Ervin

Digital landscape modeling and visualization: a research agenda

Abstract Digital landscape models, whether made for purposes of ‘visual inference’, or for simulating and understanding behavior or other invisible aspects of the landscape, require abstractions and simplifications. Yet for many visual purposes, ‘realistic’ depictions are desirable. The conflicts between these two demands are substantial for landscape modelers. For the basic landscape elements — terrain, vegetation, and water — some standard techniques for convincing static visual representation have been developed, but many complicating questions and obstacles remain. In addition, landscapes are essentially dynamic, and digital techniques for representation of these dynamics are still in their infancy. Surveying these techniques, complications, and possibilities leads to some generalized comments about the promises and problems of landscape modeling, and to a handful of proposed research topics to help pursue the landscape modeling agenda.

Landscape Visibility Computation: Necessary, but Not Sufficient

In this essay we review the major developments in the history and techniques of landscape visibility analysis, providing a number of examples and identifying a few critical challenges to the community of those who would seek to evaluate visibility—and related characteristics such as visual quality or preference—in landscapes. We argue that visibility per se is a necessary prerequisite, but insufficient in itself, as a basis for the common planning, design, and public policy questions in the context of which many visibility analyses are instigated.

Landscape visualization with Emaps

Emaps, a comprehensive environment for displaying geographic data, written in object-oriented Common Lisp and running on a Macintosh computer, is described. In Emaps, a hierarchy of objects-windows, maps, cells-takes advantage of the class-instance inheritance and generic methods of Common Lisp to allow prototyping and exploring of variations. The combination of a class library of objects, a protocol for accessing them, ready access to the full display capabilities of the computer, and the interpreted nature of Lisp make for an interactive environment for visualizing landscapes and exploring geographic information.<<ETX>>

Visualizing n-dimensional implications of two-dimensional design decisions

Experiments in visualizing implications of landscape planning and design decisions using a combination of GIS, CAD, and video animation technology are described. Simple grid-cell GIS databases and site-scale polygonal models are used to provide visualizations of site planning design proposals and environmental impact, with both static and animated images. Rather than pursuing photo-realistic simulations, the focus is on how abstractions and representational conventions can be used to gauge visual and environmental effects of proposals for landscape change, in a dynamic interactive computer-aided design environment.<<ETX>>

A hypermedia GIS : the Massachusetts Turnpike study

Abstract This article describes an information system developed at the Harvard Graduate School of Design in support of a landscape analysis, planning and design project concerned with the Massachusetts Turnpike. This system includes both vector and raster GIS database and analysis software; a video disk containing some 6000 sequential images of the study area; image processing software for producing and editing color bit-maps and producing hard-copy; hyper-media database management and exploration software; and spreadsheet software for statistical analysis and data visualization. The system is selfcontained on a Macintosh IIcx workstation, using commercial software, and linked through a local-area network to other computers for access to a larger database, more complex GIS analysis, and other services such as CAD software.