Cartographic maps

Thematic Mapping

 Thematic maps use different visualization techniques to show the assoication between a geographic area and a theme. Thematic maps are useful to help provide information about spatial patterns, and to compare locations. There are 4 types of thematic maps: choropleth, isarithmic, dot, and proportional symbol maps.  

Choropleth Map

Obesity has grown to become a risk factor for many chronic diseases in the United States. This choropleth map shows the prevalence of obesity in the United States for each state in 2008. A choropleth map is a useful tool that aggregates data by geographical areas. It improves communication between public health professionals and the public by using a simple visualizing technique with different colors and/or shading that represents the statistical data for the topic analyzed. In this map the variation in shading and colors represent the prevalence of obesity in each state based on the statistical information gathered by the National Center for chronic Disease and Health Promotion. The lighter colors and shading indicate a low prevalence of obesity, while the darker shading represents high prevalence rates for obesity.

Isarithmic maps

Isarithmic maps are contour maps that contain continuous and smooth phenomenon using isolines that represent constant values over geographic areas. This map is an isarithmic map that indicates hydrogen ion concentration from field laboratories in 1998.

Dot Density Map

A dot distribution map uses dots to represent the presence of a phenomenon in a geographic area. Dot maps create a visual impression of density and should be used to represent raw data. The dots on this map indicate the amount of tobacco produced in each state. In this map 1 dot represents 1,000,000 pounds of tobacco grown.

Proportional Symbol Map

                       

A proportional symbol uses symbols of different sizes to represent data relative to that location. This map shows the number of lynchings for each state from 1882-1968. The size of the symbols depends on the number of lynchings found in that state. This information is useful for formulating corresponding death rates in the United States.   

            

                             Environmental Sensitivity Index Map

Environmental Sensitivity Index  (ESI) Map shows a compilation of coastal resources at risk for an oil spill. The information provided allows public health professionals to plan cleanup strategies before an accident occurs and save natural resources.  Shoreline are color coded to show their sensitivity to to oiling. The back of most ESI maps have tables showing when species are present in the areas shown on the front of the maps and indicate their seasonality, breeding times, and threatened/endangered status. 

References:
Heer, J. (2010, May 23). A Tour through the Visualization Zoo . Retrieved from ACMQUEUE: http://queue.acm.org/detail.cfm?id=1805128

Marzulli, F. N. (1942). THE EFFECTS OF HYDROGEN ION CONCENTRATION UPON THE METAMORPHIC PATTERN OF THYROXIN- AND IODINE-TREATED TADPOLES. Journal of General Physiology, 623-647.

National Oceanic and Atmospheric Adminstration. (2014). What is an environmental sensitivity index map? Retrieved from National Oceanic and Atmospheric Adminstration: United States Department of Commerce: http://oceanservice.noaa.gov/facts/esimap.html