Fetal Death Definitions

Mapping Units
Visible Layers
Base Layers
Definitions
Map Tools

Presentation Information

All numbers and rates pertain to the place of residence (not occurrence).

If an Age group, Race, Sex, Ethnicity or Education Level are chosen, all rates/percentages include only the choices in both the numerator and denominator.

Maps are used to emphasize the spatial distribution of one or more geographic attributes or variables. This site generates choropleth maps as thematic maps in which the geographies are shaded different colors to represent different magnitudes of a variable.
The map projection is Lambert Conformal Conic.

Confidentiality rule:: Numbers based on 0-4 events are classified as a separate static class when a sub-county level geography (Census Tract or County Commission District) is chosen. This is done to assure confidentiality.
Not Reportable: At the County level or higher rates (and percents) based on 1-4 events are not reported due to statistical reliability reasons. At sub-county level (Census Tract or County Commission District), rates and percents based on 0-4 are not reported. This assures confidentiality.
Trendable Maps: Trendable maps are a series of choropleth maps showing change in spatial distribution of data in a selected area over selected period of time. Trendable maps share the same data class breaks which allows easy comparison between each map in the series.

Mapping Units:

County to create a map of a selected geography: counties, Public Health District(s) or Perinatal Region(s); or
Public Health District to create a map of the state by the 18 Public Health Districts; or
Perinatal Region to create a map of the state by the 6 Perinatal Regions; or
County Commission District or Census Tract to create a map of a selected geography: counties, Public Health District(s) or Perinatal Region(s)

Visible Layers:

Census Tracts 2020: Census Tracts are small, relatively permanent statistical subdivisions of a county or equivalent entity that are updated by local participants prior to each decennial census.; Census tracts generally have a population size between 1,200 and 8,000 people. A census tract usually covers a contiguous area; however, the spatial size of census tracts varies widely depending on the density of settlement. Census tract boundaries are delineated with the intention of being maintained over a long time so that statistical comparisons can be made from census to census. Census tracts occasionally are split due to population growth or merged as a result of substantial population decline.; Census tract boundaries generally follow visible and identifiable features. They may follow nonvisible legal boundaries, such as minor civil division (MCD) or incorporated place boundaries in some states and situations, to allow for census-tract-to-governmental-unit relationships where the governmental boundaries tend to remain unchanged between censuses. State and county boundaries always are census tract boundaries in the standard census geographic hierarchy. Reference Source: U.S. Commerce Department, United States Census Bureau, February 2022.
Cities/Towns: A mix of both incorporated places (legal entities) and census designated places or CDPs (statistical entities). An incorporated place is established to provide governmental functions for a concentration of people. Places always nest within a state, but may extend across county and county subdivision boundaries. An incorporated place usually is a city, town, village, or borough, but can have other legal descriptions. CDPs are delineated to provide data for settled concentrations of population that are identifiable by name, but are not legally incorporated under the laws of the state in which they are located. Click on city/town name to highlight the boundary. Reference Source: U.S. Census, 2020.
County Commission Districts: For more information, see http://www.accg.org/. The districts were established in 2014, and were obtained from the Association of County Commissioners of Georgia (ACCG). Further processing was performed by the Office of Health Indicators for Planning (OHIP) of the Georgia Department of Public Health. History and role: In 1868 the state began creating the position of county commissioner to administer the general operations of the county. Today every county has a commissioner; many have a board of commissioners (BOC). As part of general county operations, the BOC must finance county programs. A BOC has the power to adopt ordinances, resolutions, or regulations relating to county property, county affairs, and the operation of local government (http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-589 ).
GA House Districts: Electoral districts from which State Representatives are elected. The Georgia Constitution requires not less than 180 Representatives apportioned by population from representative districts. Layer Source: https://www.legis.ga.gov/, Adopted 2021 – Effective for 2022 Elections.
GA Senate Districts: Electoral districts from which State Senators are elected. The Georgia Constitution limits the number to not more than 56 single member districts. Senate districts are apportioned based on population. Layer Source: https://www.legis.ga.gov/, Adopted 2021 – Effective for 2022 Elections.
Hospitals: Hospitals are the non-Federal acute-care inpatient medical facilities in Georgia. Click on the symbol to get the name. Reference Source: Georgia Hospital Association, 2021.
Interstates: Interstates are the freeways that are part of the Interstate Highway System in Georgia. The Interstate Highway System connects major cities within the United States. Click on the line to get the Interstate number. Layer Source: Esri, March 1, 2012.
Major Roads: Major roads are a combination of both federal and state highways connecting cities and towns. Click on the line to get the route number. Layer Source: Esri, March 1, 2012.
Perinatal Regions: The Perinatal Regions were established by the Department of Public Health in cooperation with the six teaching hospitals located in Atlanta, Albany, Augusta, Columbus, Macon and Savannah. The Regions reflect the hospital referral patterns for high risk pregnant women and newborns Each of the six hospitals has a Regional Perinatal Center which has contracts with the state and receives funding to care for high risk pregnant women and infants as well as to train staff from other hospitals in perinatal care especially for high risk patients. Reference Source: Georgia Department of Public Health, March 2005.
ZIP Code: Established by the U.S. Postal Service for distribution of mail. Zip codes do not generally respect political boundaries or census areas such as tracts. Zip codes usually do not have clearly identifiable boundaries, often serve a continually changing area, are changed periodically to meet postal requirements, and do not cover all land area in the U.S. Layer Source: Esri, June 1, 2020.

Base Layers:

Base layers are background information to provide contextual references for local-level maps. They are especially suited for tract-level maps and give real-world reference to maps you create in OASIS. There are three toggle-able (on/off) base layers:
Demographic Clusters: Demographic Clusters refer to the socioeconomic status classifications created by OHIP, and are at the census block-group level. More information here: https://oasis.state.ga.us/gis/demographiccluster/DemoClusters2011.htm
Aerial Photography: Aerial Photography refers to ESRI's World Imagery.
Socioeconomic (SES) Vulnerability: Socioeconomic (SES) Vulnerability refers to the socioeconomic status domain/subset of the CDC’s Social Vulnerability Index (SVI) 2020. Socioeconomic vulnerability ranks census tracts within Georgia on 5 factors: below 150% poverty, unemployed, housing cost burden, no high school diploma, and no health insurance. Percentile ranking values range from 0 to 1, with higher values indicating greater vulnerability/lower socioeconomic status. Quintiles of the percentile rankings were used to create class breaks (Very Low, Low, Average, High and Very High SES Vulnerability). Keep in mind that “Very Low” SES Vulnerability equates to a High SES status. For more information see https://www.atsdr.cdc.gov/placeandhealth/svi/index.html. For data dictionary click here.
Street Map: Street Map refers to ESRI's World Street Map with street-level data for North America.

Data Classification Methods:

Natural Breaks (Jenks)

This method minimizes within-class variance and maximizes between-class variance in an iterative series of calculations. This method seeks to partition data into classes based on natural groups in the data distribution. Natural breaks occur in the histogram at the low points of valleys. Breaks are assigned in the order of the size of the valleys, with the largest valley being assigned the first natural break.

George F. Jenks is considered a pioneer in GIS educational programs. Through an award from the Fund for Advancement of Science, Jenks identified four key objectives for cartographic training. Robert McMaster and Susanna McMaster; A History of Twentieth-Century American Academic Cartography

Source: Brewer and Pickle. Evaluation of Methods for Classifying Epidemiological Data on Choropleth Maps in a Series. Annals of the Association of American Geographers, 92(4), 2002, pp. 662-681.

Quantiles

Data values for each enumeration unit (e.g. county or census tract) are ranked from lowest to highest.
The total number of values is divided by the number of classes specified by the user to determine how many values each class will contain. The object is to obtain a roughly equal number of data values within each class. For example, if you have 100 census tracts and the tract data values are to be classed into 5 classes, each class will have 20 values (100/5 = 20).
In some cases, an equal number of values will not be placed into each class. For instance, if there are an odd number of enumeration units some classes will have a larger number of data values than others. If data values for the 159 counties of Georgia are divided into 4 classes, then some classes might have 39 data values while others have 40. In addition, identical data values are maintained within the same classes. Continuing the Georgia county example, if 45 of the lowest data values are 0, then the lowest class will have 45 data values all with a value of 0.

The quantiles method of classification is provided because:

Quantiles classification is one of the simplest methods of classification and is easy to understand and interpret.
Classes are usually centered on the median, a measure of central tendency, and "they group enumeration units above and below the median into classes with equal frequencies regardless of their values." This makes maps easier to compare with one another.
Many health-related measures are distributed normally (i.e. a large number of values falling near the middle of the data range with a smaller number of values on the low and high ends of the data range) making quantiles classification a logical classification method.