TopoL NT technology

The new generation of TopoL technology is based on following fundamental principles. Its open modular architecture is based on the standard OLE/COM/OCX technologies for Win32 environments (Windows 95/98/NT/2000). Access to vector-oriented spatial data is based on database principles; i.e. spatial vector data are viewed in the context of database management technologies.

The modular architecture of TopoL NT technology satisfies following rules:

• is based on the OGC's ( OpenGIS Consortium) Pluggable Computing Model;
• makes inclusion of the TopoL technology and spatial data into the context of larger and complex enterprise-wide information systems easier;
• allows to deploy customised solutions for needs of specific applications and customers;
• supports the use of third-party components to augment the technology.

The new concept of data access satisfies following principles:

• is based on the standard OLE DB technology for Win32 environments, which makes possible to access data in different formats in a uniform way;
• follows principles defined in the OpenGIS Simple Feature Specification, which provides interfaces for uniform access to vector spatial data;
• makes accessible data in the current proprietary TopoL format to any system using above given specifications without any need for data conversion;
• makes possible to store any data including geospatial objects into standard database management systems (relational or object-based) and access them using the standard query language SQL92 (or SQL3/MM after its standardisation).

The fundamental principle of the new technology is the complete change of its architecture to component-based (using the COM specification). Geospatial data access is also changed to database and table-oriented, so that spatial data can be easily integrated within common information systems. Above given rules presents clearly that TopoL NT technology closely follows Windows standards and OGC's specifications. The new TopoL technology will include step by step components supplying overall TopoL GIS functionality (e.g. remote-sensing data processing, specific photogrammetric tools - orthorectification, image correlation, etc.) and will take advantage of our deep experience in GIS and RS development. The concept of open system architecture enables us to incorporate components of other GIS vendors (e.g. for DEM processing of the Atlas firm).

TopoL NT technology components

The technology currently consists of several component sets, which were used during TopoLCarto development. Following list shows some of them and illustrates features, which could share applications built with them. This list should not be considered as exhaustive and other components are expected to be prepared.

Vector spatial data access components

Data connector concept is used with TopoL NT technology for data access implementation. A data connector for vector spatial data consists of several objects, which provides OLE DB interfaces. This standard Windows technology makes possible to access common database tables as well as other data sources, which can be seen as tables. TopoL NT technology includes connectors for spatial vector data, which support data retrieval from common database systems (e.g. Microsoft Access, Microsoft SQL Server), from the current proprietary TopoL GIS format and from the public ArcView Shapefile format. One TopoL data block is exposed in the form of a database, which contains tables for each individual TopoL object group (feature class).

Raster spatial data access components

Data connectors for raster data enable us to read and write image files irrespective of their format. TopoL NT technology currently supports following image formats without any need for conversion: TopoL RAS (including RAK variant), TIFF, Windows BMP, CIT, and PCX.

Components for definition of presentation characteristics

These components make possible to define presentation characteristics and order within display or printing area. Vector data presentation characteristics are also closely related to components for standard and user-defined cartographic symbol and text style presentation. For easier definition of thematic maps, display table (transfer) components are provided for colour, cartographic symbol and text style specification.

Presentation components

These components display data on the bases of the definition of presentation characteristics. Raster, vector, text annotation, and map sheet presentation components are available within the TopoL NT framework.

Other components

Other component sets include spatial reference system and transformation management, support for map sheets, project and document management etc. These components supply services for other components and final applications as well.

TopoL NT technology components are used besides of TopoLCarto in the TAXCarto application. Raster data access and raster presentation components are used in the new version of Orbis Mapper product developed in the TopoLPro firm.