To create and maintain a trusted database of addresses that enables users to describe and share locations, it is necessary to implement several formal, technical and practical tasks that are described in this chapter.

To define the boundaries of the different areas that form part of an address it is necessary to establish an area division for the administrative validity area of the addressing system. It is necessary that the boundary of the administrative validity area is well defined geographically.

The administrative validity area is hierarchical and consists of two levels. The first level is for the system itself and equals the national boundaries of the Sultanate of Oman - all addressing units within the country must be addressed according to the National Addressing System standard.

The second level is reserved for administrative division. In the National Addressing System, the second level is reserved for the combination of governorate and wilayat. The purpose of this level is to provide a high-level geographical differentiation between locations inside the country.

From the point of view of naming, it is beneficial to have the possibility to use the same street name in two different administrative validity areas. However, it should be avoided in adjacent areas near administrating validity area borders.

This permits the continued use of existing street names that exist in several places in the country. It will also enable new names to be repeated several places in the country, reducing the number of new names that must be identified and allocated unique names. An example of a street name that already exist several places in the country is Sultan Qaboos Street, a name that is used among other places in both Muscat and Dhofar governorates.

Once areas were not planned at the time of building a city and once the road infrastructure has not been built in understanding with such an area division, there is no easy way to define areas retroactively. Both trying to assign absolute boundaries to existing names as well as introducing new areas is time consuming and difficult. Thus, it is preferable to take as a starting point an existing area division that is well known and agreed upon.

For areas other than the administrative validity area their significance in the addressing system is not a mandatory part of the formal address but as destinations that will aid people to navigate to addresses using the road network.

The importance of areas is for signage and wayfinding. For this purpose, it is enough to know where you must make a turn or an exit to enter an area. For this reason, destinations are typically represented as a point on the road infrastructure inside an area, e.g. an intersection. The exact boundaries of such areas are of little importance.

A destination hierarchy typically consist of three hierarchical levels, called primary, secondary and tertiary destinations. In this document the term “first level” is equivalent to primary, “second level” to secondary and “third level” to tertiary.

Primary destinations are important destinations that are sign posted from the exits on main thoroughfares and arterial roads with high-speed limit. The primary destinations will typically include the administrative validity area of the addressing system.

Secondary destinations are destinations that are sign posted from minor arterial roads and collector roads.

Tertiary destinations are either small named communities/neighbourhoods or civic services or points of interest that are sign posted from minor collector roads and local access streets.

First and second level destinations are usually areas; tertiary destinations are commonly a mix of local area names and individual points of interest.

An example, using existing area names in Muscat governorate include:

• Primary destination (sign-posted 10+ km away): Mutrah
• Secondary destination (sign-posted 1+ km away): Hayy al Mina
• Tertiary destination (sign-posted at exit from collector or local access road)
  • Local area name: Sur Al-Lawatia
  • Attraction: Souq al Sammak
  • Civic services: Sultan Qaboos Port

Areas used in destination hierarchies can overlap and exist in any number of hierarchical levels. In signage, it is usual to constrain the number of different signs to three levels, meaning that all tertiary, quaternary etc. destinations will share the same type of street signage.

While the boundaries are not significant, any names must have a unified spelling in Arabic and a version of the name using the letters of the English alphabet in a manner to imitate the sound of the Arabic name¹ must be standardized for consistent usage in writing and on signage – as well as to facilitate spoken exchange of addresses between Arabic speakers and users of foreign languages.

Having decided the point of origin, streets may be defined. Streets are a series of connected line segments that form an unambiguous axis along which address units may be identified and numbered. Streets are drawn as centre lines in a map.

Plazas, squares and circles may also be denoted as streets. In such cases the street will only have numbered addressable object on the “outside” of the line geometry that delineates i.e. the plaza.

Streets must be classified according to their function, as different rules will apply for street identification for major arterial and collector streets as well as minor local access streets. The National Addressing System will adopt the classification published by the Ministry of Transport, Communications and Information Technology (MTCIT) in cooperation with the municipalities.

The introduction of an addressing system does not improve the accessibility of addressable objects, it just eases the process of identifying their location. In the Sultanate of Oman today there exist areas without formal road access but with addressable objects.

In such cases, instead of numbering addressable objects to imagined and non-existent streets, the street will be replaced by an area within which addressable objects will be assigned unique numbers.

Once streets are defined, the segments that belong together and should have one name must be assigned a system identifier, typically a numeric value that is used by IT systems and applications for referencing a street. Streets should also have a public identifier, typically a name, a number or a combination of name and number.

A street name may consist of several elements:

• A name part such as “Mazoun”
• A directional part such as “North”, “N” or “South”, “S” etc.
• A designator such as “Street” or “Road”
• A sequence number such as “1”, “2” or “3”

For the name part of street identifiers, the same principle applies as for area identifiers – any name used for identification should have a standardized spelling in Arabic as well as a consistent transliteration to “English² letters” for consistent use in writing, on signage and in speech.

To assign address unit identifiers it is necessary to determine what should be addressed. Address units are planned and reserved based on a variable distance along a street. Address units are commonly assigned to public entrances, buildings, gates, parks — or even plots if there is any visible structure to attach a sign to. The purpose of the address unit is to identify a delivery point for goods people or services that is so accurate that if a user arrives at the given address, it is easy to identify the location of the recipient.

Some addressing system uses plots as addressing unit, but since one plot may contain many buildings, this may cause difficulties in identifying the location of a recipient. Such difficulties are acceptable when it comes to mail or parcel delivery – but is more problematic when it comes to emergency response.

Each single address unit will be represented in a map as a geographical point. This point will have coordinates.

To facilitate way-finding, address units are typically sequentially numbered along a street. The most common way of numbering address units is to assign the first building on the left side of the street number 1, the first building on the right side 2, the second building on the left side of the street 3, the second building on the right side of the street 4 etc.

Figure 2: Examples of numbering schemes for address unit identification

In cases where an address unit identifies a location with multiple delivery points, such as a multi-dwelling unit, sub-addresses are used to specify the recipient's location. This applies, for example, to closed compounds and residential high-rise buildings.

For existing buildings and compounds, established numbering systems will be applied. For new constructions, a standard will be used whereby a sub-unit will be identified by a combination of the floor it is located on and the number of the sub-unit on the floor. Apartment 402 should be the second apartment on the fourth floor.

A standardized sequence of floor numbers must be agreed – as well as a numbering direction (e.g. clockwise) for units on a floor. Similarly, it is necessary to identify permissible sub-unit designators such as “office”, “villa”, “apartment”, “flat”.

This information must be collected through modification of existing processes by the municipalities or the utility providers in the country. It may be possible to force the collection of sub-address units at the time of renewing tenancy contracts, similarly it may be possible to do it at the time of renewing utility contracts.

The public elements of addressing systems are targeted at people. Today, the usefulness of the addressing system is however closely linked to its successful adoption in information technology driven CRM and public services delivery processes.

It is common for such systems to store the complete address redundantly. This is however a practice that is sensitive to typing errors and makes it more complicated to geocode an address to a location by referencing the addressing data. Even more so in the Sultanate of Oman where multiple alphabets are used.

A better practice is to implement cascading search forms that permit users to select addresses by specifying area, street and building number using drop-down boxes that are populated incrementally as the user selects the hierarchically superior element.

Having identified the address, the remote system stores an address code rather than the full text of the address. This permits easy lookup of coordinate locations and/or updated names if the spelling of these is changed.

In the National Addressing System where the digital system will precede both the physical implementation and the naming process for individual streets, the address code is envisaged to be very important.

In systems where the post code identifies individual addresses rather than areas or streets, it is common for the address code and the post code to be the same. This has the added benefit that it is possible to use a code that the public is familiar with as the only input to identify a location, i.e. in a navigation system.

If using codes that are already supported by mainstream navigation providers, i.e. Map Codes (Here, Navteq) or Open Location Codes (Google) the address code can be used without any implementation effort on the part of the organization that has authority over addressing.