Gazetteer References & Data Sources
Database & Map Update Cycles
- The Physical, Cultural, and Historic Features geographic data is updated 6 times per year. Last update: August 25, 2021.
- The ZIP Code database and ZIP Code maps are each updated 4 times. The database was last updated on April 1, 2023 and the maps were last updated on February 3, 2023.
- The School Attendance Zone Maps are updated 4 times per year. Last update: March 24, 2023.
- The Demographic Data is updated annually. Last update: July 1, 2022.
Source of Geographic Data
The geographic data is provided by two US Geological Survey (USGS) data products. The first one is the Geographic Names Information System (GNIS), the official Federal database for domestic geographic feature names and locative information. The second one is data downloads from The USGS National Map.
Source of Demographic Data
The annual census demographic estimates and 5-year forecasts are based upon data produced by Esri Demographics. Their estimates and forecasts use the latest US Census Bureau annual American Community Survey (ACS) as a starting point. They then combine additional data from multiple sources including residential postal delivery counts from the USPS, a time series of county-to-county migration patterns from the IRS, building permits, housing starts and local data sources that tested well against the most recent census. For more detailed information: Methodology Statement: 2022/2027 Esri Updated Demographics.
Source of School Profile Information
The primary data source for our school profiles is the National Center for Education Statistics (NCES) at the US Department of Education.
Source of Maps, Map Data, and Boundaries
- The base maps, terrain maps, and satellite views are produced by HERE. They also provide the driving directions.
- The defined boundaries for neighborhoods, incorporated places, Census Designated Places, counties and county subdivisions that overlay the maps are derrived on data provided by Esri.
- Both the School Attendance Zone Maps and ZIP Code Maps are derived from data provided by Precisely. Precisely is a new company that was formed when Synscort and Pitnery Bowes Software & Data combined into one organization. Their customers include 90 of the Fortune 100 largest U.S. corporations.
- The Congressional District Maps are based on data provided by the U.S. Census Bureau
Geocoding and Nearby Places
- Forward Geocoding, taking an address and translating it into geographic coordinates, is performed by HERE. Reverse Geocoding, finding the geographic coordinates of a point on a map and then calculating the nearest address to it, is also performed by HERE.
- The data for the "Places" section of the Community Profiles for cities, towns, villiages, Census Designated Places (CDPs), and ZIP Codes is provided by FOURSQUARE.