5. Task 4: System Functions
5.2. System functions specification
According to the Needs Assessment23, the core needs for a DRB GIS should be satisfied by a
toolset for information production, handling, and dissemination. The DRB GIS will make environmental geoinformation available via the Internet and should be the foundation database for further common (geo)datasets of the Danube River Basin.
The four common needs of user groups identified in the Needs Assessment are: > maps
> a system on the overview scale
> a centrally initiated and developed GIS database > public access
The most important system functions of the DRB GIS are outlined in the Strategic Plan24:
> Provide data for Member States GIS
> Receive information from Member States GIS
> Provide information for ICPDR users, Member States GIS, and external users including the public
The system functions are designed using UML (Unified Markup Language). The use case diagram is a state-of-the-art way to explain system functions on the basis of a common language. To facilitate mutual understanding, comments describing the use cases are added. A detailed specification of the most important use cases is integrated in Annex C. For a detailed description of special workflows, activity diagrams are added to show when, where, from whom and how input is required or output should be provided. These diagrams are added to the tool descriptions when necessary to understand the workflow in the background.
23Towards a Danube River Basin GIS: Needs Assessment and Conceptual Design for the Danube River Basin
GIS System, KTH, Department of Land and Water Resources Engineering, Stockholm, 2003.
Figure 22 delineates the use cases necessary to differentiate. From top to bottom, the roles within the blue frame (DRB GIS system) successively receive more tools and privileges to change the input of the system. For example, the data input user may access every tool from the user above (the expert user), but not from the user below (e.g. the administrator). A detailed view of the use cases is portrayed in chapters 5.3 (Data handling functions & conversion requirements), 5.4 (Access & Security functions), and 5.5 (WebGIS client functionalities and OGC interfaces).
> Public User: any web user who is interested in the condition of the Danube. He/she will be able to view dynamic maps with a WebGIS application (use case: "views public WebGIS"). Querying of the database is integrated, but only "pre-defined", simple queries are available and not the whole content of the DRB GIS database can be viewed (use case: "calls pre-defined queries").
> Expert user: this user also has access via the Internet but to gain more information than the public user, special system privileges are provided ("authorized user"). The expert user inherits all user rights from the public user, and the rights are extended to viewing more complex maps (use case: "views expert WebGIS") and querying more information from the database (use case: "creates advanced queries"). This user has the specialised knowledge to realize when datasets are wrong and can submit an error message to the data input user (use case: "submits data errors"). Since this user is interested in creating reports (use case: "creates reports") she/he is usually also has the right (granted by the data input user) to download data (use case: "downloads data"). The purpose may be creating the WFD roof report (use case: "creates Roof report") or any other kind of report (use case: "creates any report").
> Data input user: This user's main activity is the delivery of data to the Danube River Basin GIS (use case: "uploads data"). The data input user represents the ICPDR Member States' GIS user who releases the data (and metadata) and who wants to retrieve GIS data from the DRB GIS (use case: "downloads data", inherited from the expert user). Before data upload occurs, schema mapping of national data to the schema of the DRB GIS dataset can be conducted (use case: "maps national data to DRB schema"). After the decision maker has permitted publication, the data input user releases the datasets of her/his country to the public WebGIS (use case: "releases final data version").
> Administrator: The administrator is responsible for maintenance of the whole system architecture with all its functions. The installation of users and their associated roles is one of the main tasks of the administrator (use case: "manages users"). She/he is not involved in the thematic content of the portal but in the appropriateness of the web application and the database (use case: "administrates portal").
Outside the DRB GIS:
> Reconcile user: This user is a special data input user with extended rights. The institution/person responsible has to be nominated by neighbouring countries. She/he supervises the matching of transboundary datasets and thus has to communicate with national data input users to get commitment to the shared boundary areas (use case: "reconciles data"). The result of the matching process is submitted to the data input user. Since the data input user remains responsible for his/her national data and thus can also reject the reconcile user's suggestion, the reconcile user is an optional role.
> There is one decision maker per country who is responsible for the data in a legal sense. The decision maker permits the publication of data sets (Use case: "permits publication"). The data input user can release the final data version at her/his disposition.
Figure 22: Use cases for DRB GIS
While an information system like the DRB GIS provides a toolkit for information supply, business processes can not be handled solemnly with these tools, but also need support from outside the actual system. The DRB GIS thus provides a variety of different instruments, while the optimal workflow also includes aspects that lie beyond the mere technical solution. In Figure 22, the blue frame comprises the DRB GIS' system scope. The decision maker and the reconcile user, however, are working in a national legal framework with strong connection to WFD-reporting. Their main tasks lie outside the actual system, on a higher level of integration (e.g. the role of the reconcile user includes consultation with the national mapping agencies involved).