Dutton e-Education Institute and Assistant Program Manager for Online Geospatial Education, and Adrienne Goldsberry, Senior Lecturer, John A. Dutton e-Education Institute, Beth King, Senior Lecturer, John A.

Dutton e-Education Institute Ryan Baxter, Senior Research Assistant, John A. Instructors and contributors: Jim Sloan, Senior Lecturer, John A. Dutton e-Education Institute, and Director of Education, Industry Solutions, Esri. As illustrated in the map below (Figure 3.17.4), the use of an unlimited set of color hues to symbolize unique data values leads to a confusing thematic map.Īuthor: David DiBiase, Senior Lecturer, John A. This symbolization strategy is designed for use with a small number of nominal level data categories. This option assigns a unique color to each data value. For this reason some might be tempted to choose ArcMap's Unique Values option to map rates, densities, or even counts. Logically or not, people prefer colorful maps. Most textbook cartographers would approve of this, since they have long argued that it is the lightness and darkness of colors, not different color hues, that most logically represent quantitative data.

Color ramps are sequences of colors that vary from light to dark, where the darkest color is used to represent the highest value range. Users may choose a group of predefined colors, known as a color ramp, or they may specify their own custom colors. Users can adjust the number of classes, the class break values that separate the classes, and the colors used to symbolize the classes. Because our ability to discriminate among colors is limited, attribute data values at the ratio or interval level are usually sorted into four to eight ordinal level categories.

Population density map of the us