OpenDX stands for Open Data Explorer and is IBM's scientific data visualization software. It can handle complex domains (such as a mechanical gear or a human brain) along with

measured Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared t ...

or computed data. The data may be

scalar Scalar may refer to: *Scalar (mathematics), an element of a field, which is used to define a vector space, usually the field of real numbers * Scalar (physics), a physical quantity that can be described by a single element of a number field such ...

(such as the concentration of a chemical agent in the brain), vector or tensor fields (like the displacement or strain tensor fields when the gear is in action) at different points of the object. The points at which data is measured don't have to be equally spaced and not need to be homogeneously spaced. The project started in 1991 as ''Visualization Data Explorer''. ''OpenDX'' can produce 3D images with the quantities plotted as color or gray-scale coded, or as vectors, streamlines and ribbons. It allows the object to be sliced to obtain a view of the internal structure, and then represent the data on this slice plane as a height-coded graph. It can rotate the object to provide a view of the data from any angle and allows animations of this motion to be made.

Graphical user interface

''OpenDX'' is based on the

Motif Motif may refer to: General concepts * Motif (chess composition), an element of a move in the consideration of its purpose * Motif (folkloristics), a recurring element that creates recognizable patterns in folklore and folk-art traditions * Moti ...

widget toolkit on top of the X Window System. Its graphical user interface has a wide variety of interactors, both direct and indirect. Direct interactors allow the user to directly manipulate images (e.g.

rotate Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...

or zoom). Indirect interactors ( dials, switches, buttons, sliders) enable the user to control various aspects of her visualization. Interactors are ''smarter'' because they are data-driven. Interactors are auto-ranging and self-limiting. They examine the data and, depending on its type, will determine the minimum and maximum of the data, or create a list for an option

menu In a restaurant, the menu is a list of food and beverages offered to customers and the prices. A menu may be à la carte – which presents a list of options from which customers choose – or table d'hôte, in which case a pre-established seque ...

based on the data. The user can even set the label of the interactor based on some aspect of the data (e.g.,

metadata Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive ...

The data-driven concept is not simply for sliders, dials and option menus. It also applies to vector interactors. These reconfigure themselves based on the dimensionality of the data. They also auto-range themselves based on the maximum and minimum of each vector component.

Design

Data Explorer is a system of tools and user interfaces for visualizing data. In general terms the visualization of data can be considered a 3-stage process: * Describing and importing data * Processing the data through a visualization program * Presenting the resulting image. The principal components of OpenDX are ; Data model: This is the set of definitions, rules, and conventions used to describe Data Explorer entities (including data fields, geometrical objects, and images). ; Data Prompter: A user interface for describing data to be imported into Data Explorer. ; Data Browser: A user interface for viewing a data file, determining the layout and organization of the data it contains, and transferring this information to the Data Prompter. ; Scripting Language: A high-level language for creating visualization programs. It can also be used directly in a command mode to perform various tasks. Visual programs—i.e., the visualization programs displayed in the Visual Program Editor window as ''networks'' of module icons—are also written in the scripting language. A visual program constructed in this window by the user is translated into the same language when it is saved to disk. ; Visual Program Editor (VPE): A graphical user interface for creating and modifying visual programs (networks). Programs created with this editor are translated into the scripting language by Data Explorer and are stored in that form. ; Modules: The ''building blocks'' (visualization ''tools'') that constitute a visual program network. They can be directly accessed and manipulated in the ''Visual Program Editor''. ; Module Builder: A user interface for creating customized modules to be used in visual programs. ; Image Window: An interactive window for viewing and modifying the presentation of the image produced by a visual program. ; Control Panels: A user interface for changing the parameter values used by a visual program.

Screen shots

Visualization of a scalar field

In this example we show the visualization of the flow of a particulated material (dust) inside a building. In this case the quantity visualized is a scalar, namely the concentration of the particles. The concentration of particles at each point in space is represented using colors. The reader can deduce the concentration by comparing the colors with the ''colorbar'' at the right upper corner of the image. To improve the visualization the drawing is shadowed as if it had an elevation in the direction normal to the plane proportional to the concentration. In OpenDX this is called the ''rubber-sheet'' effect.

Visualization of vector fields

Vector fields are harder to visualize than scalar ones. Consider in this case the flow in a cubic cavity (the 3D version of the well studie
square cavity
benchmark. The use of streamlines helps in realizing the direction of the flow. The ''rockets'' (the big red arrows on the top of the cavity) represent the imposed flow.

External links

*{{official website, www.opendx.org (out-of-date)
Commercial support, physical media
(out-of-date)
module
for reading HDF5 files Data visualization software Free software programmed in C OpenDX