As noted in the first edition of Geography in America, the term “remote sensing” was coined in the early 1960s by geographers to describe the process of obtaining data by use of both photographic and nonphotographic instruments (Gaile and Wilmot 1989: 46). Although this is still a working definition today, a more explicit and updated definition as it relates to geography can be phrased as: “remote sensing is the science, art, and technology of identifying, characterizing, measuring, and mapping of Earth surface, and near Earth surface phenomena from some position above using photographic or nonphotographic instruments.” Both patterns and processes may be the object of investigation using remote sensing data. The science dimension of geographic remote sensing is rooted in the fact that: (1) it is dealing with primary data, wherein the investigator must have an understanding of the environmental phenomena under scrutiny, and (2) the investigator must understand something of the physics of the energy involved in the sensing instrument and the atmospheric pathway through which the energy passes from the energy source, to the Earth object, to the sensor. The art dimension of geographic remote sensing has to do with the creative ways that the scientific interpretations are presented for visualization and measurement. The technological dimension of geographic remote sensing has to do with the constantly evolving hardware, software, and algorithmic manipulation and modeling involved in the collection, processing, and interpreting of data regarding the Earth phenomena under investigation. It is the rapidly advancing combination of these three dimensions over recent decades that has brought remote sensing to be a vibrant and dynamic part of the discipline of geography today. We wish not to dwell at length on the historical aspects of remote sensing as it relates to geography. This has been done quite adequately in the first edition of Geography in America as well as in other publications, such as the American Society of Photogrammetry and Remote Sensing (ASPRS) Manual of Remote Sensing series (e.g. Colwell 1983), that is now going through a third edition and complete update, and is being presented as a compendium of individual volumes that deal with specific aspects of remote sensing science.