VisIVO Tools VisIVO Tools

VisIVO is an integrated suite of tools and services for effective visual discovery in currently available (and next-generation) large-scale astrophysical datasets.

VisIVO consists of VisiVO Desktop - a stand alone application for interactive visualization on standard PCs, and VisIVO Server - a grid-enabled platform for high performance visualization.

The main characteristic of VisIVO is to support high-performance, multidimensional visualization of very large-scale astrophysical datasets. Users can obtain meaningful visualizations rapidly while preserving full and intuitive control of the relevant visualization parameters. This section focuses on VisIVO Server allowing intuitive visual discovery with 3D views being created from data tables. VisIVO Server can be installed easily on any web server with a database repository.

VisIVO Server consists of three core components: VisIVO Importer, VisiVO Filter and VisIVO Viewer. To create customized views of 3D renderings from astrophysical data tables, a two-stage process is employed. First, VisIVO Importer is utilized to convert user datasets into VisIVO Binary Tables (VBTs). Then, VisIVO Viewer is invoked to display customized views of 3D renderings.

A VBT is a highly-efficient data representation realized through an header file (extension .bin.head) containing all necessary metadata, and a raw data file (extension .bin) storing actual data values.

VisIVO Importer converts user-supplied datasets into VBTs without imposing any limits on sizes or dimensionality. It supports conversion from several popular formats such as: ASCII and CSV, VOTables or FITS Tables. VisIVO Filter is 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 are typically employed for constructing reduced VBTs to perform a sub-sampling in order to fit it in the available RAM memory. VisIVO Viewer is based on the Visualization ToolKit library for multidimensional visualization. It creates 3D images of datasets rendering points, volumes and isosurfaces within a bounding box used for representing the coordinate system employed. Moreover there is support for customized look up tables for visualization using a variety of glyphs, such as cubes, spheres or cones.

The VisIVO Library was developed to port VisIVO Server on gLite middleware. It allows a job running on a grid node to produce a set of images or movies directly using VisIVO with its internal data arrays without the need to produce intermediate files. This is particularly important when running on the grid, where the user wants to have a quick look of the results during the data production phase. The images in this way can be produced directly in the grid catalogue, while the user code is running in a system that cannot be directly accessed by the user (a worker node).