geocode

Geocoding is the process of transforming non-spatial data such as street addresses, place names, or postal codes into geographic coordinates that can be used on a map or in spatial analysis. The term geocode is commonly used as a shorthand for this process, with geocoding as the noun and to geocode as the verb. It enables linking tabular data to geographic locations. There are two main forms: forward geocoding, which converts an address or place name into coordinates; and reverse geocoding, which interprets coordinates to return an approximate address or place.

Forward geocoding relies on reference data such as street networks, gazetteers, and administrative boundaries. The result is typically a pair of coordinates (latitude and longitude), possibly with an ambiguity score or confidence level and metadata about the match type, source, and accuracy. Outputs may also include a projected coordinate system or a supplied precision.

Reverse geocoding starts from a coordinate pair and returns the nearest street address, place name, or area, sometimes including the estimated accuracy and the associated location hierarchy.

Geocoding commonly relies on public or commercial datasets and geocoding APIs. Providers include global and regional street datasets, and services that return coordinates with accompanying metadata. Data quality, locale rules, and name disambiguation affect results. Privacy considerations arise when geocoding personal data.

Applications include mapping and visualization, routing and navigation, proximity searches, geospatial analytics, and emergency response. Accuracy varies with data quality, coverage, and the granularity of the input. Standards often use WGS 84 (EPSG:4326) coordinates, though other systems exist.