Dot-Density Shading: A Technique for Mapping Continuous Climatic Data

Abstract

Traditionally, spatial distributions of continuous climatological variables have been displayed using isolines. The placement of isolines involves an assumption about the gradient of the variable being mapped. Because of the numerical value associated with an isoline, a degree of precision is associated with this type of map that may not be justified. Dot-density shading offers an alternative technique for displaying these spatial distributions. The continuous nature of the dot-density display makes it an effective means of thematically depicting variations in the magnitudes of climatological variables. This is demonstrated by maps of various climatological variables for Colorado and from an experimental global climate model.