[en] Systems that allow users to store and retrieve spatial data, provide for analyses of spatial data, and offer highly detailed display of spatial data are referred to as geographic information systems, or more typically, GIS. Since their initial usage in the 1960s, GISs have evolved as a means of assembling and analyzing diverse data pertaining to specific geographical areas, with spatial locations of the data serving as the organizational basis for the information systems. The structure of GISs is built around spatial identifiers and the methods used to encode data for storage and manipulation. This paper examines how GIS has been used in typical environmental assessment, its use for cumulative impact assessment, and explores litigation that occurred in the United States Federal court system where GIS was used in some aspect of cumulative effects. The paper also summarizes fifteen case studies that range from area wide transportation planning to wildlife and habitat impacts, and draws together a few lessons learned from this review of literature and litigation.

[en] One of the more common activities of environmental scientists in the United States is the preparation of environmental assessments or environmental impact statements in response to the mandates of the National Environmental Policy Act. The central thesis of this paper revolves around a frequent dilemma those scientists face: how to proceed with the environmental impact analysis when information on potential impacts is incomplete or unavailable. The paper examines how the 'hard look' standard that U.S. courts have imposed upon agencies considering proposed actions came about. Further, U.S. courts have said agencies cannot make arbitrary and capricious decisions when deciding to build a project, implement a plan, issue a permit or other give other approvals, and this paper discusses how the courts have defined what arbitrary and capricious decision are, especially when decisions are made when information about impacts is incomplete or unavailable. The paper examines why agencies win or lose lawsuits filed against the environmental assessments or environmental impact statements they write, focusing on those cases that have occurred after the Supreme Court ruled on the issue in 1989. The paper suggests recommendations to environmental scientists faced with incomplete or unavailable information when preparing an environmental assessment or environmental impact statement in the U.S