Geocoding relies on a computer representation of address points, the street / road network, together with postal and administrative boundaries.
Geocoding – a subset of Geographic Information System (GIS) spatial analysis – has been a subject of interest since the early 1960s.
On 1 July 1963, five-digit ZIP codes were introduced nationwide by the United States Post Office Department (USPOD).
In 1967, a team at the Census Bureau – including the mathematician James Corbett[3] and Donald Cooke[4] – invented Dual Independent Map Encoding (DIME) – the first modern vector mapping model – which ciphered address ranges into street network files and incorporated the "percent along" geocoding algorithm.
DIME was intended for the use of the United States Census Bureau, and it involved accurately mapping block faces, digitizing nodes representing street intersections, and forming spatial relationships.
In the late 1970s, two main public domain geocoding platforms were in development: GRASS GIS and MOSS.
The early 1980s saw the rise of many more commercial vendors of geocoding software, namely Intergraph, ESRI, CARIS, ERDAS, and MapInfo Corporation.
[6] This database – along with the Census' nationwide coverage of households – allowed for the birth of TIGER (Topologically Integrated Geographic Encoding and Referencing).
In 2003, geocoding platforms were capable of merging postal codes with street data, updated monthly.
For example, parcel-centroid allowed a geocoder to determine the centroid of a specific building or lot of land.
An APN is important for geocoding an area which is covered by a gas or oil lease, and indexing property tax information provided to the public.
This involved geocoding a numerical point location – with a longitude and latitude – to a textual, readable address.
Thus, it is common to first go through a process of data cleansing, often called "address scrubbing," to find and correct any errors.
This is especially important for databases in which participants enter their own location geocodes, frequently resulting in a variety of forms (e.g., "Pennsylvania," "PA," "Penn.")
Finally, several caveats on using interpolation: A very common error is to believe the accuracy ratings of a given map's geocodable attributes.
One study[10] by a group of Iowa researchers found that the common method of geocoding using TIGER datasets as described above, can cause a loss of as much as 40% of the power of a statistical analysis.
Emergency services, for example, do not make an authoritative decision based on their interpolations; an ambulance or fire truck will always be dispatched regardless of what the map says.
[citation needed] In rural areas or other places lacking high quality street network data and addressing, GPS is useful for mapping a location.
In contrast to geocoding of structured postal address records, toponym resolution maps place names in unstructured document collections to their corresponding spatial footprints.
In addition to scientific publication, the new approach and subsequent prototype gained national media coverage in Australia.
[16] Geocoded locations are useful in many GIS analysis, cartography, decision making workflow, transaction mash-up, or injected into larger business processes.
Geocoding, along with GPS provides location data for geotagging media, such as photographs or RSS items.
Law enforcement agencies have experimented with alternative geocoding techniques that allow them to mask a portion of the locational detail (e.g., address specifics that would lead to identifying a victim or offender).