Lifting the fog: maps and spatial information emerging as grey literature

Maps as a genre are not typically dealt with in the study of grey literature. The transformation of information from maps to spatial data could likely be omitted from discussions as well. The author argues for an approach that focuses not on product, but on content. Three types of grey map presentations are profiled: a series, the US Geological Survey’s (USGS) Open‐file Report series; a collection, the Long Island Sound Resource Center; and an annual publication, the Environmental Sciences Research Institute’s (ESRI) Map Book. Significant research issues are indicated.