Geoscience Reference
In-Depth Information
state, which are responsible for the real estate cadastre and state survey (Official
German Surveying and Mapping), cooperate within the Working Committee
(AdV, URL:
http://www.adv-online.de
) of the Surveying Authorities of the States
of the Federal Republic of Germany to discuss technical issues of fundamental
and nationwide importance targeting standardized regulations.« This includes the
determination of common standards for the acquisition of 3D Building Models
across Germany. In 2012 AdV decided a product standard for 3D Building
Models. According to that, the building ground plans are derived from the offi-
cial digital cadastral map and the buildings are represented as blocks uniformly
with a flat roof in the so called first detailed level (Level of Detail 1—LoD1).
Since 2013 a central LoD1-dataset is initially assembled which is expected to be
centrally delivered in the middle of 2013. The data exchange between the states
and the central service center uses a nationwide uniform profile of the AdV based
on the City Geography Markup Language (CityGML) Encoding Standards from
OpenGIS® and the Open Geospatial Consortium (OGC) Specification CityGML
1.0.0.
The future is three-dimensional. Photo-realistic motion pictures impress the
viewers. There is a demand for the local authorities, to take part in the digital
revolution. Up to now, inter-department web based viewers (e.g. BayernAtlas,
EnergieAtlas Bayern) and applications for overall national planning of land use or
standard land value are available in geodata infrastructure projects. All of these are
two-dimensional.
With the assignment of the 3D-topic to the AdV, the authorities follow the
trend. Vendor independent standards for 3D City Models and digital surface mod-
els (DSM) had to be developed. In this context, the states had to start with the pro-
duction of City Models according to standard guidelines.
The AdV-CityGML-profile is designed for the delivery of building data with
standardized roof shapes as building models of the second detailed level (LoD2)
with optional photo-realistic textures. The degree of automatic recognition of roof
shapes and the elevation accuracy of the automatic roof reconstruction are on the
one hand dependent on the degree of generalization of the roofs to the standard
roof forms and on the other hand based on the acquisition basis. If Light Detection
And Ranging (LiDAR)-data rom airborne laser scanning is used for the acquisi-
tion, then the density of the point cloud is significant. When oriented aerial photo-
graphs are used, the accuracy of the orientation elements and the point allocation
determines the quality of positional and elevation accuracy. The usage of the
building outlines simplifies the building reconstruction from LiDAR-data and aer-
ial images (Vosselman
2002
; Rottensteiner and Briese
2003
). The ISPRS bench-
mark on.
3D Building reconstruction (Rottensteiner et al.
2012
) contains three out of
seven different methods, which use building outlines or building maps.
Independently from the used acquisition method and the underlying dataset an
update after the first acquisition of a 3D Building Model has to be ensured. This
requires a comprehensive concept containing the first acquisition, the data man-
agement and the update process combined in one workflow.
