Information Technology Reference
In-Depth Information
workflow for remote importing. This workflow allows the generation of signi
cant
information for metadata exploration, e.g., statistics on data values, histogram
calculation and plotting, or a sample extraction of uploaded datasets. Such metadata
is available through the properties portlet, and some can be modi
ed by the user
(e.g., renaming VBTs or related
fields).
The VisIVO Filter portlet allows users to apply a collection of data processing
modules to modify a VBT or to create a new VBT from existing VBTs. The
filters support a range of operations such as scalar distribution, mathematical
operations or selections of regions. For example, decimation or randomization is
typically employed for constructing reduced VBTs to perform a subsampling in
order to
lter
operations are performed, and the portlet automatically displays all applicable
operations allowing input of the relevant parameters. Analogously to the VisIVO
importer portlet, this portlet employs the gUSE ASM API to submit several
workflows to allow the
it it in the available RAM memory. Typically various VisIVO
filtering operations and the generation of metadata of the
processed dataset.
The VisIVO Viewer portlet employs the visualization toolkit (VTK) [VTK]
library for multidimensional visualization. It creates 3D images of datasets ren-
dering points, volumes and isosurfaces within a bounding box used to represent the
coordinate system employed. By using interactive widgets, users can construct
customized renderings, or store data analysis and visualization results for future
reference. Moreover, there is support for customized look up tables for visualization
using a variety of glyphs, such as cubes, spheres or cones.
The VisIVO portlets are independent of each other, and navigation between
them is made possible by a menu located on the upper side of the portal web page
and from the interaction with the data management portlet. The datasets are
managed internally through a relational database that preserves their metadata and
maintains data consistency. Figure 13.2 shows the main portlets of the Gateway
connecting VisIVO importer,
filters and viewer services.
To create customized views of 3D renderings from astrophysical data tables, a
sequence of simple actions is required to rapidly obtain meaningful visualizations.
First, the VisIVO importer portlet is utilized to convert user datasets into VisIVO
VBTs. Then, the VisIVO viewer portlet is invoked to display customized views of
3D renderings. A right-click on any processed dataset in the data management
portlet is used in conjunction with the View button to create user-prescribed Vis-
IVO Viewer views. VisIVO Gateway further allows users to generate scienti
c
movies. These can be useful not only to scientists to present and communicate their
research results, but also to museums and science centers to introduce complex
scienti
c concepts to general public audiences.
Users can access a panoramic movie portlet to submit a workflow which creates
a movie of a given dataset on a camera path of 360
°
±
°
in azimuth and
90
in
s domain. The customized movie portlet allows the
generation of movies produced by intermediate snapshots of a dataset speci
'
elevation within the dataset
ed as
camera positions/orientations by the submission of a workflow. Finally,
the
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