CityGRID Manager

Overview

CityGRID Manager is the core software around which CityGRID is structured.  It uses a platform independent database to manage all of a city’s building and construction models.  Each model is defined by its line structure and photo texture.

CityGRID Manager uses a database to manage all of a city’s building and construction models.  Each model is defined by its current line structure and photo texture and can be opened using its unit ID assigned by the user, its address or a user-defined area of interest.  Building units are imported using CityGRID Modeler using the XML interface or AutoCAD.  Building units are displayed in CityGRID Modeler for editing.  A VRML interface is included for virtual reality visualisation, for example in CityGRID Explorer.  User-defined areas of the city model can be uploaded to CityGRID Planner for simulating projects.  Derived databases can be used for 2D analysis in the GIS or for 3D visualisation in ArcScene/ArcGlobe.  A relational database system is required for installing Manager.  CityGRID currently supports Microsoft SQLServer and Oracle.

Efficient database administration

CityGRID uses lines as the basis of defining a unit’s geometry, meaning it is compact and ideal for database supported administration.  Even textures can be stored within the database.  Using RDBMS means that users can utilise all the advantages that the environment has to offer, applied to true 3D data.  For example, concurrent editing allowing multiple users access to the city model simultaneously.  Transactioning prevents corruption of those edits, and versioning means the editing history of a unit can be tracked at any time.  The original unchanged measurements are always available and never lost.

Scalable solutions

The CityGRID Manager license is scalable and can be designed to meet the needs of municipal users.  The following Levels of (geometric) Detail (LoD) are available:

Figures:

• top left: LoD1 - Block Model with superstructure base version
• top middle: LoD2 - Form model (Optional)
• top right: LoD3 - Roof and façade texture (Optional)
• bottom left: LoD3+ - Detailed façade modeling (Optional)
• bottom middle: LoD4 - Interiors / Underground installations model (Optional)

The solution allows city centres to be illustrated at varying levels of detail (block, roof detail and texture) and the remaining areas can be illustrated at the simplified block level.  The actual built-up area (the size of the area multiplied by building density) is used to determine license costs.

GIS Integration: ArcGIS Extension for CityGRID Manager

CityGRID Manager manages the 3D line structure and the photo texture (if available) for each building or construction unit.  The unit is displayed graphically as a surface model in real time using powerful triangulation algorithms.  This data structure is ideal for creating and updating 3D objects.  We can derive appropriate records for use in GIS.  For conventional 2D GIS’s, lines and surfaces are derived, and 3D information is used to calculate additional attributes such as building height to enable analysis using 3D information.  3D visualisation is currently only possible in the ArcScene and ArcGlobe modules from ESRI.  Manager can generate surface models in Multipatch format for this purpose.

2D Analysis in GIS

Numerous specialised applications still use analyses and simulations based on 2D information.  CityGRID Manager generates a 2D GIS data pool with additional attributes.  For example, 3D roof information can be used to create a 2D area theme with the additional attributes “roof exposure”, “roof pitch” and “inclined roof area”.  GIS can then use this information to analyse which roofs in the city meet the general prerequisites for installing sun collectors, for example.

3D visualisation in GIS

The ArcScene and ArcGlobe modules from ESRI can be used to illustrate large areas of the city model correctly and combine then with results from analyses, for example.

2D analysis with façade information

The facade information contained in the city model, such as the facade surface area, facade height and width, or facade orthophoto, is linked to the “facade” linear theme in the GIS.

Viewshed analysis

CityGRID Manager calculates a grid depth image that contains the site and the modelled building objects for calculating viewshed analyses in the GIS.  GIS modules such as ArcGIS Extension 3D Analyst can be used to simulate places in the city where a new highrise project would be visible, for example.  Municipal department 41 (surveying) of the city of Vienna was kind enough to provide us with the figure opposite.

3D analysis in GIS

CityGRID Manager derives a 3D surface model for 3D-capable GIS modules such as ESRI ArcScene and ArcGlobe.  These 3D models of buildings and underground railway structures can be combined with other GIS themes such as the pipework plan and can be retrieved as single spaces.