The late 1980s saw an extensive development of marine computer simulators ensuring excellent cost-effective training of high-class specialists in the sphere of navigation. Developing along with the computer simulators are the databases (scenes) for them, i.e., virtual models of environment, of its physical properties. The production of such databases is a high-tech process using the most up-to-date and costly computer equipment in the conditions of permanently growing requirements for the end product quality which should comply with the electronics development level and competition terms within the framework of a limited number of users. Another specific feature of the database production for the computer simulators is that it requires highly professional personnel capable of being easily adapted to the changes in the production procedure and quality level. In these circumstances, the key factor determining the economic efficiency and flexibility of this kind of production is a spatial data modelling system (SDMS). This work describes approaches to the creation of a SDMS and their implementation in TRANSAS

　

 The know-how of creating SDB for the marine simulators has a number of specific features allowing it to bee singled out into a separate direction of the spatial design. These specific features include:

　

 The aforementioned technological characteristics determine the main problems in the creation of SDB for the MNS, which include the shortage of source data, technological difficulties, shortage of qualified personnel, technical problems.

　

 The shortage of source data is determined by the partial absence of non-availability of digital charts for the modelled area. This dictates the necessity for the user formation of digital data from the paper charts, plans, drawings and photographs. More often then not, data from different sources does not correlate with each other, and the operator has to manually associate it.

　

 Technological difficulties consist in that the SDB generation procedure is a creative process, which takes from several weeks to several months to complete, the achievement of the ultimate result being strictly dependent on the human factor. The subjectivity of assessing the final data quality makes the production planning process rather problematic.

　

 The qualified personnel problems originate in the requirement to have fundamental knowledge not only in the spatial design area, but also in the navigation, radio navigation, cartography and other spheres connected with navigation. This causes considerable time and material expenditures involved in the training of SDMS operation specialists, and consequently, complexity of flexible organisation of the production and technology advance.

　

1.2 Analysis of the Structure of SDMS Users

　

 SDMS users can be arbitrarily divided into professionals and non-professionals. Professional users are specialists whose principal line of activities consists in the SDB production. As a rule, this kind of production is organised with the aim of further distribution of the SDB for the MNS, or providing of consultancy services . The professional production requires considerable investments for its organisation.

 A professional user of the spatial database system should be a specialist in the spatial design, and in this case, the capability to create a 3D object of any complexity level and of high visual quality is a mandatory requirement imposed on the SDMS along with the accuracy of the navigational information display.

　

 Non-professional users are specialists whose principal line of activities is connected primarily with the operation of MNS, they are normally professionals in the sphere of navigation and are not proficient in the spatial design. Non-professional users create SDB to be used in their own simulator and do not, as a rule, impose stringent requirements on the visual quality of data. The main criterion in the assessment of the SDMS is easiness of operation and accuracy of the navigational data display.

　

 Professional users make up 1-2 per cent of the MNS market; these are major consultancy and training centres and some regional distributors of simulator products. Theoretically, the remaining 98 per cent of the market belong to the non-professional SDMS users, i.e., to the rest of the MNS users. Unfortunately, the non-professional SDMS users' market is now practically not covered; this is due, to a great extent, to the fact that the user has no idea about the availability of a simple-to-use SDB production technology.

　

1.3 Components of a SDB for the MNS

　

 Depending on the simulator module, which uses a certain part of the SDB, data can be divided into components. Each component is normally presented in its own format, e.g., the visual component may use Open Flight for its format. The main data components are visual, radar and chart components. Proceeding from the simulator training goals, the necessary set of components may vary:

　

　

 It is important to note that regardless of the final set of components, the SDB production should be carried out within the framework of a single SDMS, the number of created components reduced through cutting down the system functionality.

　

1.4 Tasks fulfilled by the SDMS for the MNS

　

 Regardless of the user category, the SDMS for the MNS is intended for the accomplishment of the following main tasks:

　

 The expected demand for the fulfilment of the aforementioned tasks for the professional and non-professional user is set forth in the table below:

　

　

 Therefore, the sole difference in the requirements between the professional and non-professional SDMS sets consists in the availability of the spatial editor of polygonal data; examples of this are provided by the commonly known programs like AutoCAD, Multigen, Studio Max. For this reason, the rest of the tasks should be accomplished within the framework of a technology ruling out the direct polygonal modelling and oriented to the user basically familiar with the marine software applications; a typical example of such application being the ECDIS.

　

 The approach to the development of SDMS for the MNS has been worked out within the framework of SDMS4 project on the generation of "Model Wizard" product, part of solutions used unique in their area.

　

 MW system is integrated with the global collection of Transas vector electronic charts, which includes more than 9000 sheets, and provides coverage with adequate accuracy charts for any water surface fragment. In addition, the system includes a world DB on radar transponders and magnetic declinations enabling the automatic selection of necessary data for the set area.

　

 The MW includes a function for the automatic creation of a source database from the navigational charts on different scales, and elevation data from different sources. In additionally developed algorithms allow the creation of plausible surface terrains of various types for the parts of the area where the data on elevations is not available. The process of creating a 3D terrain model and display logics is automated and does not require the user participation.

　

 The base MW scene editor is built in the form of ECDIS chart layers and has a graphic user interface oriented to the marine applications. The process of the DB construction and editing consists in handling source data (depth contours, depths, heights, etc.) and making settings for the methods of 3D surface generation (textures and construction accuracy) and thus rules out the direct user editing of spatial data (polygons), which makes work on the construction of scene in the MW similar to the process of creating an exercise for the MNS. The product includes a base library of textures and 3D objects including the more typical models of port structures and cultural objects, as well as aids to navigation as per IMO specification.

　

 Data within the MW system project are divided into the following main groups: source data for the terrain formation; settings of the terrain formation methods; description of the scene objects features including links to the 3D object models and their parameters. The MW project does not, therefore, store spatial triangles, which, on the one hand, reduces the project size by tens of times, and, on the other hand, guarantees that the change of data (e.g., coastline configuration) will result in the adequate changes in the visual, radar and charts components at the time of the DB export into the simulator.

　

 Model Wizard represents a set of software modules, which enable construction, editing and viewing of the SDB components. The product can be presented in the following configurations:

　

 The first three sets allows the use of the MW by a non-professional user; at the same time the program allows the export of construction results to the commonly accepted spatial data exchange format, as well as the use of AutoCAD as a polygonal data editor, or Multigen or Studio Max as a possible alternative.

　

2.5 Analysis of efficiency of the selected approach

　

 For the analysis of the MW program operation efficiency an experiment was staged, which involved a non-professional user (training centre instructor) who used the MW program and a professional Transas designer who used one of the spatial data polygonal editors. In the course of the experiment it was necessary to create a simulator SDB for the area of the port of Kessenuma (Japan), 32 NM² in size, by using PC PIV 1.7 GHz 256 RAM. The DB included visual, radar, sensor and chart components, which described the following data: surface and submerged terrain with three levels of detail and realistic texturing, as well as the aids to navigation including light characteristics and alphanumeric notations. The production process included the following technological stages:

　

　

　

 Transas Model Wizard SDMS is intended for a broad range of MNS users including those who do not have spatial design skills, and is suited ideally for the accomplishment of the following tasks:

　

 The composite approach to the creation of the Model Wizard determines flexibility and cost-effectiveness of the system within the framework of accomplishing a broad range of tasks involved in the possible MNS use.

　

 Mr. Vladimir Ponomarev graduated from the Russian Naval College in St. Petersburg in 1993 with a BS in Hydrographic Engineering. In 1993-1998 he worked on hydrographic and oceanographic researches in the Baltic Sea and the Atlantic Ocean. Since 1998 Mr. Ponomarev works in St. Petersburg office of Transas Marine Ltd. In 1998-2001 he organized spatial database development group for marine simulators and worked as the Group Leader. In 2001 Mr. Ponomarev took the leadership over the Spatial Database Development Software group.

　

 In 2003 Mr. Ponomarev was promoted to Manager of Marine Navigation Simulators Development department.