the design and planning level up to political and entrepreneurial level will be addressed during the project initiative based on the
central Energy Atlas platform. On higher levels, policy makers require a high level of abstraction. Basically, an engineer will
focus on energy flows and balances for individual buildings and its proximity, while a more global view will be relevant for
areas of responsibility of a designer or administrative. The greater the area of responsibility is, the more a spatial
aggregation is required to support the decision making process. Figure 1 illustrates this correlation.
The Energy Atlas will facilitate the integration, spatial visualization and analysis of energetic and ecologically relevant
information; energy requirements and consumption; energy streams and distribution; energy sources and production; and
shares in the production, but also in the reductions of greenhouse gas emissions.
Core of the Energy Atlas is the virtual 3D city model of Berlin [Berlin3D, 2009]. The official 3D city model of Berlin consists
of about 550,000 buildings in LOD2, about 100 buildings landmarks in LOD3, and 4 buildings in LOD4 with integrated
Digital Terrain Model. The model is structured according to the CityGML standard and provides geometry, topology, semantics,
and appearance in an integrated way for all buildings in Berlin.
Figure 2: Starter Project Energy Atlas Berlin: Core and Application Fields
In the center of the technical framework of the Energy Atlas, the storage of the 3D city model and all integrated datasets is
implemented using 3DCityDB [3DCityDB, 2012], an Open Source 3D geodatabase structured by a CityGML conforming
relational database schema developed by the Institute of Geodesy and Geoinformation Science of Technische Universität
Berlin see [Stadler et al., 2009] for detailed information. Figure 2 shows the structure of the Energy Atlas framework
with the central database providing functionalities for gathering and calculating energy related objects and properties together
with their semantic information.
2.1 CityGML
The City Geography Markup Language CityGML is an international standard issued by the Open Geospatial
Consortium OGC for the representation and exchange of semantic 3D city models. It specifies classes and relations for
the most relevant city objects in an object oriented way including geometrical, topological, semantic and appearance
properties, generalization and aggregation hierarchies between object classes as well as thematic relations between city objects.
CityGML is an application schema of the Geography Markup Language 3.1.1, based on a number of standards from the ISO
191xx family, OGC, W3C Consortium, Web 3D Consortium, and OASIS [Gröger et al., 2008; Kolbe, 2009]. The language
provides thematic modules for the representation of buildings, city furniture, land use, relief, and vegetation, traffic
infrastructures and water ways including a full 3D geometry representation and the ability of enrichment by application of
specific data, e.g. values concerning energy planning. However, the thematic modules can only cover a basic set of application
fields. For use in further domains CityGML provides concepts of generic objects, generic attributes, and Application Domain
Extensions ADE. An ADE can extend CityGML by specific attributes or objects in a formalized way to cope the additional
thematic requirements. Five consecutive Levels-of-Detail LOD are defined within
CityGML, with increasing detailing in spatial and thematic differentiation from LOD0 2.5D DTM + 3D landmarks and
infrastructure up to LOD4 most detailed 3D structure including an indoor model. Each object may have attached a
separate representation for each LOD simultaneously. The full coverage of geometry, topology, semantic, and
appearance of city objects in diverse LODs coupled with generalization and aggregation hierarchies forming city object
structures on different hierarchical scales and the ability of designing domain specific extensions build a stable
environment
for performing
multi-scale analyses
and simulations on CityGML-conforming virtual 3D city models.
2.2 Starter Project Energy Atlas Berlin: Data and Concept
Integration to cope with Application Fields
Within the initial project Energy Atlas Berlin, in cooperation with academic partners from several departments of the
Technische Universität Berlin and the German Research Centre for Geosciences GFZ; the industrial partners Vattenfall
Europe Berlin AG, GASAG AG, and Berlin Partner GmbH; and the Berlin Senat for Economics, Technology and Womens
Issues as partner of the city government of Berlin; the application fields geothermal heat potential, traffic urban
structure, energy characteristics of buildings, and the creation of new business models will be addressed, see Figure 2. For that
purpose, energy relevant features, e.g., for energy production, distribution, and consumption will be identified and
incorporated. In addition, analysis and visualization tools will be designed and prototypically implemented, such that a
visualization of analysis results in combination with the 3D city model of Berlin is available, allowing a visual interpretation
related to the urban environment. The 3D city model of Berlin itself provides the geometry of
buildings as well as a basic set of semantic information, such as building addresses, usages, and heights. Data integration of
existing energy-related datasets and integration of additional modeling concepts is one prerequisite to augment the model
according to the energy domain requirements. For that purpose, the following datasets and concepts are incorporated into the
3D city model of Berlin:
•
Datasets with solar potentials of the Solar Atlas Berlin [Solaratlas, 2010] obtained from laser surveying of about
500,000 roofs in Berlin are available for buildings and also
Figure 1: Energy Atlas – Levels of Decision-Making
Building Energy Properties,
Balance and Scenarios
Geothermal Heat Potential
Traffic and Urban Structure
Innovative Business Models
Modeling and Data Survey Modeling and Set-Up CityGML
Energy ADE and Database Definition
Data Integration, Implementation of Tools for Analyses and Energy
Assessment Visualization Interaction
Berlin CityGML Energy Atlas
XXII ISPRS Congress, 25 August – 01 September 2012, Melbourne, Australia
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for single roof surfaces. The datasets contain slope and orientation of the roofs; the amount of solar irradiation;
installation costs, energy yields and CO
2
reduction potentials for different solar panel types.
•
The modeling concept of an Utility Network ADE which incorporates supply infrastructures and utility networks
i.e. gas, water, electricity, etc. into CityGML is contributed by another project called SIMKAS-3D
Simulation of Cascading Effects in the Failure of Utility Infrastructures [Simkas3D, 2010] which deals with
scenarios of cascading effects among supplier networks of Berlin’s utility companies that may result in disasters. The
definition of the core network model and its relationship to additional packages can be found in [Becker et al., 2011].
•
Concepts for estimation of the energetic rehabilitation state of buildings and heating energy consumption are
incorporated from [Carrión, 2010 Carrión et al., 2010].
Figure 3: Energy Atlas Berlin: Model and data Integration
Figure 3 illustrates the integrative approach of the Energy Atlas Berlin. Network modeling concepts, Berlin-wide solar potential
data for roofs and the 3D city model dataset of Berlin have been already joined for the Energy Atlas.
2.3 Applicability within other Cities
