Map Projections

1. National Maps

To facilitate the presentation of information for all U.S. counties, several different map projections were used. For the coterminous United States an Albers–Conic Equal Area projection was used. Alaska was projected to the Miller Cylindrical projection and Hawaii is presented using geographic coordinates (latitude and longitude). Neither Alaska nor Hawaii is to proper geographic scale relative to the continental United States. The combinations of projections and scales allowed the presentation of a relatively familiar orientation of these geographic features.

The coordinate information for the contiguous United States was projected using the Albers Equal–Area projection with the following parameters:

The coordinate information for Alaska has been projected using the Miller Cylindrical project with the following parameters:

2. State Maps

All state maps were projected using the State–Plane projection systems of each state. The state maps are presented to maximize the reader's ability to interpret results for each state and are therefore not to proper geographic scale relative to one another. However, State–Plane coordinate systems are commonly used by state agencies and therefore their use here maximizes the reader's ability to compare these maps with other information.

Many states did not have significant populations of women and men of particular racial and ethnic groups. In many cases racial and ethnic specific rates could not be calculated for any of the counties within the state. Rather than present blank maps for these states, we elected to generate race and ethnicity–specific state maps only if there were at least two counties with heart disease mortality rates for any given racial and ethnic group.

Back to Top

Date last reviewed: 05/12/2006
Content source: Division for Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion