Defining the Palouse:Using Overlap Analysis to Delineate an Informal Region Forrest Bowlick (bio), Koehler Andermatt, Cathy Besmar, Josh Erbe, Robert Lopez III, Joe White, Daniel W. Goldberg, and Katherine M. Carroll The Palouse is a unique region of loessal hills and astoundingly productive agriculture. Located generally in the inland Pacific Northwest, the Palouse lacks a rigid definition, and varying fields define the Palouse with widely different limits and boundaries. We provide a method using overlap analysis in a geographic information system (GIS) analyzing the varying regional definitions to determine what portions show the greatest overlap, or agreement, within the disparate fields. We determine that a “core” Palouse is easily apparent, though the “border” or “fringe” of the Palouse is much wider and uncertain. Introduction The Palouse is an area of high-yield agriculture in the inland Pacific Northwest, composed of fertile loess in east-central Washington (Treasher 1925). Or, it is a rolling topography of high-relief hills located in Whitman County, Washington, and Latah County, Idaho (Kirkham et. al. 1931). It could be defined as an area of fragmented prairie remnants (Looney and Eigenbrode 2012), or described while considering varying linear topographic structures across Washington, Idaho, and Oregon (Lewis 1960). Suffice it to say, the Palouse (or any region) exists within a number of different definitions. Overall, the Palouse “area” lacks rigid definition, leading to confusing and [End Page 40] erratic labels of “regions” that are defined as the Palouse. Despite its agricultural importance, even U.S. government documents inconsistently define the Palouse either as “the region of loess rolling hills with elevations up to 900 m (3,000 ft.) and spanning 46–48°N latitude” or “eastern Washington, northern Idaho and northwestern Montana” (Muehlbauer et al. 2002 (Web), Cash et al. 1996 p. D-14). Discipline-specific definitions tend to be more precise. Early definitions focused on the soil composition of the fertile loess in east-central Washington (Treasher 1925). Other definitions weigh geomorphology with greater importance, describing the Palouse by its high-relief hill topography located within the constructed borders of Whitman County, Washington, and Latah County, Idaho (Kirkham et. al. 1931). Analyzing these varying definitions requires consideration of multiple components of each definition. These components include the various quantitative and qualitative factors present to determine what shared qualities exist within the varying constructs of the Palouse. The spatial analysis capabilities within a geographic information system can analyze these components. This project investigates these regional definitions using spatial analysis within GIS. Background Disparate fields consider the Palouse through different analytical lenses as a region. Understanding the varied definitions of the Palouse requires a diverse review of literature to discover these considerations. We identify the fields of soil science, geomorphology, ecology, and agricultural science as fields with unique and variant Palouse definitions. These definitions vary subtly and widely, and consider the “Palouse” through different frameworks and under different constructs. The first section of this background considers these varying approaches to a definition of the Palouse. The second component of this background describes existent methods for regional analysis within a GIS framework. While the region delineated here already contains multiple definitions, spatial analysis within a GIS can assist in deriving a regional construct from provided data. Cases of this regional construction are relevant to the Palouse example as specific quantitative definitions apply toward a general Palouse construct. Understanding previous methods for regional construction will guide this project’s analysis goals. The definition of any “region” will depend on scientific interests within the region, the specialization of the investigator, and the scale of investigation [End Page 41] (Omernik 1987). This variation is evident within the definitions of the Palouse. The Palouse The Palouse is surprisingly productive agriculturally despite its small area (Duffin 2005). The soil of the Palouse, deep fertile loess from glacial outflow deposited in large dunes by winds during the last glacial maximum, fuels the heavy agriculture while moderate climate and access to the Columbia River for trade create an appealing economic advantage (Duffin 2005). While the Palouse historically contained prairies, scattered remnants are all that remain of the natural bunchgrass prairie ecosystem of the Palouse since settlement and agricultural growth in the late 1800s...