TopoL 2001

TopoL 2001 is the newest product of TopoL Software company. It is the new version of TopoL GIS (previous version was 6.0). TopoL 2001 is based on TopoL NT technology. This technology has got open modular architecture based on OLE/COM/ActiveX standards for Win32 (Windows 95/98/ME, Win-dows NT, Windows 2000). TopoL NT technology is a set of components, which enable to create any application from simple viewer to map Internet server. TopoL 2001 has got the same functionality of TopoL 6.0 extended by new features of TopoL NT technology. The most important feature of the system is the freedom it offers to users and independent developers. It enables to change the user interface, to implement new special functions or entirely new applications.

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. A data connector for vector spatial data consists of several objects, which provide OLE DB, ADO interfaces. This standard MS Windows technology enables 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 enable data rading/writing from/to common database systems (e.g. Microsoft Access, Microsoft SQL Server), from/to the current proprietary TopoL GIS format (Blk) and from/to the 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). This technology repects principles defined in the OpenGIS Simple Feature Specification for OLE/COM, which provide interfaces for uniform access to vector spatial data. So any vendor can implement their own connector for their data.

This vector data access technology eases the use of geographic data within complex information systems, data storage systems and any other systems supporting ADO (ActiveX Data Object) standard. The use of ADO technology enables to convert GIS data into XML documents, which are currently assumed to be the most effective tool for data exchange or to make them public in Internet/Intranet. The data in XML format can be used in any other applications (spreadsheet) for any other processing as statistical calculations or report generations.

Data connectors for raster data enable 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, JPEG, GIF and PCX.

TopoL 2001 uses also other very important components of TopoL NT technology. It is for example memory cache with spatial index, topological tasks component or boolean operations component. The use of memory cache with spatial index speeds up some operations several times compared with TopoL 6.0. The topological tasks component is designed in that way that the editing functions offer the same comfort as the operator used to have in previous versions of TopoL. ArcView shape file can be edited in the same way. More over several ShapeFiles can be linked together (e.g. ShapeFile with polygons and corresponding ShapeFiles with lines) and when editing lines the system automatically changes the borders of polygons. Boolean operations components serve for the creation of buffers, intersections, subtractions and other logical operations.

The freedom TopoL 2001 offers, which includes the possibility to change user interface (menu, icons, hot keys), is very important. It is also possible to change editing tools or other functions very easily. This is due to the use of OLE/COM architecture for main component of the system and for all its key subsystems. Open fully documented interface of the system enables to add new OLE/COM objects developed in standard programming tools (Delphi, Visual Basic, Visual C++, etc.).

The user interface is described in XML document then. It is loaded when the system is started. The document does not describe only a menu, toolbars and hot keys, but it also defines the actions, which are processed after pressing the icon, selecting the menu command or pressing the hot key. The definition of the action includes the description of the command, which can include a sequence of procedures including simple logical definition for their execution. This concept enables to change the user interface and to modify the functionality of single functions and editing tools, with no need to change the program itself. To imagine these possibilities the brief description of single nodes of XML document follows.

The main element is Project and it includes these elements:

• Actions

  Describes all actions of the system, which can be called by the user. The names of the actions are used for the definition of a menu and toolbars. The hot key definition and a Command, which will be executed, are defined in the action.

  <Actions>
    <Action Name="Exit" Command="ExitApplication" Image="Exit" ShortCut="Alt+X">
      &Exit
      <ShortHint>Exit</ShortHint>
      <LongHint>Close all open files and exits the application.</LongHint>
    </Action>
    ..
  </Actions>

• Commands

  Includes the list of single commands (elements Command). One command is defined as a sequence of single basic procedures (elements Subcommand). The execution of these procedures can be influenced by conditions (elements If and IfNot) and jumps (elements Label and Goto). Each command has got its priority, defining if it can be interrupted or exited by another command. For example zooming can interrupt the line editing (when zoom is finished the system continues in editing) and the area creation can exit the line editing. On the other hand the raster transformation cannot be exited by zooming. The procedure definition (element Subcommand) represents the call of OLE/COM object method with any number of parameters. This object can be an object of TopoL 2001 itself or any other object of any developer. The object has to have some obligatory methods, which enable to create it and call it within the system.

• Images

  Includes the list of external images (icons or bitmaps), which are used for the definition of a menu or toolbars.

  <Images>
    <Image Name="Image1" Source="C:\WINDOWS\SYSTEM\SHELL32.DLL" ID="26"/>
    <Image Name="Image2" Source="|SamplePath|SAMPLEICO.ICO"/>
    ...
  </Images>
  

• Menu

  Includes the definition of main menu (element MainMenu) and single context menus (elements PopUpMenu). The definition of single menus includes submenus (elements SubMenu) and items (elements Item), where action is assigned.

• Toolbars

  Includes the definition of toolbars. The definition of toolbars consists of single buttons (elements Button), where action is assigned.

The set of components for the transformation of coordinates between coordinate systems enables on fly transformation of the data. It is possible to display the data captured in WGS-84 coordinate system in the same window with the data captured in Gauss-Krueger coordinate system.

The statistical calculations, analyzes under database tables with table reports extend the functionality of this newest version of TopoL GIS.