Items owned or maintained by the NPRA, or items that are of interest to the NPRA operations and maintenance departments, including applying the road network and for analysis purposes, can be defined as such features.
Features are signs, accidents, road surface, and shields as well as more abstract concepts like incidents, injuries, road conditions, and queuing.
The advantage of a centralized feature catalogue is that all features are defined and described in a standardized manner. Computer systems may then employ the feature catalogue as a component, which reduces the system development costs as well as reducing the NPRA’s expenses.
The most important characteristics of the feature catalogue are:
- It is easy to define and maintain features for all purposes.
- A simple and comprehensible machine-readable base code is developed.
- The features can be grouped, compared, and combined.
- Definitions and base code apply for all participants and technical systems within the area of road and traffic data.
The idea behind is to create an easy to use platform for “human definition” of objects; witch in turn is made into computer readable code. We also stressed the importance of making the definition process easy and logical. We believe that in this way it is possible make every definition unique. A traffic sign definition should be so precise that it will work in all of our core businesses. And if it doesn’t, it should be easy to add or change the definition so that it does.
As the feature catalogue is already established and may be employed as a component, the system owners and system developers may reduce the developing process and subsequent costs.
The Feature Catalogue Organisation
When it comes to developing the feature catalogue, only one institution within the NPRA is responsible and liable for the contents. This institution is involved in both long-term work on the catalogue and ad hoc modifications and corrections. The long-term development aim is to define and describe all technical features which will be included in the NRDB. Long term, this indicates that the feature catalogue will be implemented in all systems storing their data or accessing the road network via the NRDB. The short-term perspective focuses on prompt corrections, modifications and unanticipated needs.
This way of organising and these working methods promotes important principles:
- A feature is defined in a manner for all technical areas and fields of expertise to regard the feature as theirs. E.g. the feature “sign” is only defined once, but the managers for the technical areas of sign maintenance and of traffic signs will only be presented with sign characteristics relevant to their field of expertise.
- All systems and users gain instant and unrestricted access to the current feature catalogue.
- The feature catalogue will continue to expand without disturbing the users. The users relate only to the latest version of the feature catalogue.
- One institution (person) is liable for the feature catalogue contents. The institution and the relevant technical division organise the defining procedure.
- All qualified technical divisions have the right to propose modifications and to comment on the feature catalogue contents.
In order to define features efficiently, the number of features needs to be kept to a minimum. Thus, the following principles are introduced:
- Feature reuse. A feature defined for one technical area may be employed in other areas. E.g. the feature “resolution” can both be used in areas of speeding limits and in areas concerned with the maximum allowed axle load.
- Feature characteristics. E.g. “material” may be used for describing all physical features.
- Incident – injury – condition. Definition of “immaterial” features to support product models.