Visible Layers:

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. Each dot represents the centroid of the geographical area of the city/town. Click on the dot to get the city or town name. Reference Source: U.S. Census, January 1, 2013.
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:, 2016.
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 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, 2013.

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:
Aerial Photography
Aerial Photography refers to ESRI's World Imagery.
Socioeconomic Vulnerability
Socioeconomic Vulnerability refers to the socioeconomic status domain/subset of the CDCís Social Vulnerability Index (SVI), and is at the census tract level. Socioeconomic vulnerability ranks tracts within the state on 4 factors: below poverty, unemployed, income, and no high school diploma. Percentile ranking values range from 0 to 1, with higher values indicating greater vulnerability/lower socioeconomic status. Quartiles were used to create class breaks. For more information see 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.
The quantiles method of classification is provided because: 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.

Map Tools

Zoom In Zoom In: Select this button and then click on the map to enlarge the map. You can also click down and drag your mouse to define an area to zoom to.
Zoom Out Zoom Out: Select this button and the click on the map to reduce the map. The area where you click will be the center of the map.
Note: Select the mouse scroll wheel to zoom in or out.
Full Extent Full Extent: Select this button to see the entire map.
Pan Pan: Select this button to move the map around in any given extent.
Previous Extent Previous Extent: Click on this button to go back to the previous extent.
Next Extent Next Extent: Click on this button to go to the next extent (before previous extent)
Print Preview Print Map: Click on this button to get a printable copy of the map in PNG format as it appears at the moment. Disable any pop-up blockers. Right click on the preview and you can choose to save, copy or print the preview. The preview can also be dragged and dropped to a folder or desktop.

V1.0 (5/11/2022)