Geoscience Reference
In-Depth Information
is a standard for semantic 3D modeling of urban objects by Open Geospatial
Consortium). Domain exclusivity of metadata helps communities with homog-
enous 3D models. But, mass dissemination of 3D geospatial models is not limited
to specific domains with mutual repositories.
In such sense, this chapter presents an inventory which has been conducted
on the metadata resources that are used to publish various types of 3D geospa-
tial datasets in eight distinct geo-portals and commercial websites. The inventory
demonstrates that the current metadata either neglects 3D geospatial models or
is exclusive to native definitions of 3D models. Our investigation shows that the
current metadata requires additional information on the internal specifications of
3D geospatial models. This is why we then aim at proposing a structured set of
explicit metadata classes, fields, and suggested domain values which are generi-
cally relevant to 3D geospatial models.
The chapter is organized as follows.
Section 2
looks for and discusses the 3D
metadata requirements according to the literature on reconstruction, management,
and specifications of 3D geospatial datasets with a more particular look on 3D
geospatial models.
Section 3
presents an inventory on the metadata (schemas and
instances) of eight geo-portals and commercial catalogues to assess their suitabil-
ity for 3D geospatial models.
Section 4
presents the current version of the pro-
posed 3D metadata. The proposal is followed by
Sect. 5
which compares it to the
metadata of Canada's CGDI Discovery Portal upon three simulated scenarios. The
chapter is concluded and future perspectives are exposed in
Sect. 6
.
2 3D Metadata Requirements from the Literature
The literature on production, management, and utilization of 3D geospatial models
is quite broad (Scianna
2013
; Breunig and Zlatanova
2011
; Zlatanova et al.
2002
).
Many of the standards and commercial solutions have generic capabilities for pro-
ducing and exchanging 3D models which permit distinct users to adopt them accord-
ing to their needs and rationalities (Basanow et al.
2010
; Stadler et al.
2009
; Ravada
2008
; Nagel et al.
2008
). To have interoperability achieved and data discovery facili-
tated, metadata should explicitly indicate which geometric and thematic modeling
alternatives are employed in every 3D geospatial model. This section is going to
investigate the metadata which have been proposed alongside 3D geospatial mod-
els in the literature. The objective is to identify the requirements which have been
already indicated, the amendments which should be carried out, and the new meta-
data concepts which will come up respectively (i.e. new requirements).
The literature states that several metadata propositions have been tailored for
3D models with respect to their implications in specific domains and applications
such as 3D city models (Dietze et al.
2007
), architectural 3D archives (Boeykens
and Bogani
2008
), 3D web graphics (Flotynski and Walczak
2013
), and human
body 3D scans (Doyle et al.
2009
). These propositions agree on some metadata
requirements (i.e. concepts to be documented) such as the geometric and thematic
