Most of the things that human society cares about happen at addresses.
Where people live, work and play. Where most economic activity takes
place. Where crime happens. Where fires occur. Where
people are injured. Where goods are bought and sold. Where
products are delivered. Where services are rendered.
The address allows us to describe these locations in a way that other people can understand. It is a form of shorthand or an index by which the location can be referenced. It can be built into maps and databases that can be used to find the addressed location and to navigate to it.
In GIS databases, addresses are typically stored as address ranges along block faces (one side of a street between intersections). This is a relatively efficient way of storing address information as a large number of addresses can be referenced using relatively few attributes and graphical features. There is also a one-to-one correspondence between the street vectors and the address range descriptions. To locate an individual address, the specific address is interpolated proportionately along the vector representing the address range in which that address is contained.
This would work very well if addresses were well behaved. Range based addressing as a referencing system is however, seriously flawed. While addresses tend to observe some simple rules such as: even numbers are on the south and west sides of streets and odd numbers are on the north and east sides; numbers increase in intervals of 2; numbering starts at a central street or water feature and increases outwards from that feature, these rules are frequently broken. In commercial areas and industrial parks in particular, many numbers are unused. Numbers are frequently rounded off to create an appealing vanity address. Corner buildings frequently do not face the street upon which they are numbered. In some residential areas, numbers increase in intervals of 4 or more. In older areas, infill housing and monster homes change normal addressing patterns.
Address ranges therefore, lead to several problems:
- The number of dwellings or buildings is often far less than the number of theoretical addresses leading to an overestimation of the number of buildings and occupants
- The size of properties can vary substantially within the same area. Address interpolation assumes all lot frontages are the same, which can lead to geocoded locations that are far away from the actual location.
- Changes in land use can affect the addressing pattern. Parks, lakes and rivers, shopping centers, parking lots and other breaks in the land use pattern often result in significant breaks in the addressing pattern along the street.
- Multi-unit dwellings and commercial units may have one primary address but many secondary addresses (such as unit or suite numbers). The secondary component of the address is often left out in address databases.
- There is a one-to-one relationship with the addressable entity. This is optimal for indexing and cross-referencing.
- Non-existent addresses are avoided, resulting in a much more accurate picture of such characteristics as the density of buildings and population.
- ·Locational accuracy is substantially improved
- Non-standard addressing patterns are easily accommodated
- Ambiguity of reference is avoided.
- Data maintenance and quality assurance are facilitated because point addressing is more stable than address ranges and can be specifically validated.
Point level addressing is particularly beneficial for those applications that are dependent upon locational precision and/or lack of address ambiguity. These applications include:
- Emergency Services (Police; Fire; Ambulance; Homeland Security; Disaster Response)
- Location based services (LBS)
- Infrastructure management (linking physical plant and customers)
- Determination of serviceability (is a given service available at a given location)
- Delivery services (mail and courier services; in-field technicians; trucking)
- Address management (consolidated invoicing; common customer view; CRM)