Geocoding is the process of determining geographic coordinates for place names, street addresses, and codes (e.g., zip codes). Geocoding is typically preceded by the data cleaning step of preprocessing and standardizing the format of the data you will be geocoding. Related tasks include:
Batch geocoding: geocoding multiple addresses, place names or codes at one time.
Reverse geocoding: determining the nearest street address for a given point location specified as a latitude and longitude.
Currently the best, most accurate, freely available tools for the UCB community. They include:
The Esri World Geocoding Service provides high quality geocoding for place names, addresses and zip codes within the USA. It also works with locations outside of the USA, but in sometimes more limited ways. Global coverage is documented here: https://doc.arcgis.com/en/arcgis-online/reference/geocode-coverage.htm
For more details on getting started with the Esri tools check out this tutorial guide written by the D-Lab and the Library - Geocoding Options with Esri software and data: A Guide for the UCB Community
Great accuracy and currency, with global coverage. Requires programming to access (R, Python, javascript, etc.) and limited to 2,500 free geocodes per day.
Easy to use graphic interface for geocoding addresses. Just upload a file of up to 1,000 addresses. Has the option of outputting census lookup codes (FIPS codes for census tracts). There is an API for this service as well if you want to programmatically geocode more than 1,000 addresses at a time.
The MMQGIS plugin is a Python plugin for QGIS that contains geocoding tools, which can draw on the Google Geocoding API data, the OpenStreetMap Nominatim service, or a local street address layer, such as the US Census Bureau's TIGER/Line data.
What's the best way to format my data for geocoding?
This depends on which service you are using -- different tools have different requirements. Some will want you to put all of the address information into a single field, while others require the components of the address to be separated into different fields. Check the documentation for whichever tool you are using.
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The following StreetMap North America datasets are available on the GIS workstations in the Earth Sciences & Map Library, as part of the Esri Data & Maps products. Ask at the reference desk for help accessing the data.
UCB faculty, staff, and students with an active CalNet ID can use the Esri site license for geocoding if the output of this process is for research, teaching, or other academic activity.
Computers in campus libraries (including dedicated GIS workstations in the Earth Sciences & Map Library), Geospatial Innovation Facility, and D-Lab all have computers with Esri software installed. The D-Lab also has computers with the geocoding data referenced in this document locally installed. If you would like this software installed in your department’s computer lab, contact your computer lab manager.
Do not use an online geocoding service, a public access computer or a networked computer with restricted use data (RUD). Restricted use data may include data about sensitive topics, or deal with vulnerable populations, proprietary information, or personal identifiers. If your data deal with human subjects, you should make sure the ways you are protecting the data conform with IRB requirements and campus minimum security standards. Contact the D-Lab or the Research Data Management program for information on working with RUD.