Climate

Synopsis Provides an example application encompassing the following features and capabilities: Multiple graphical display windows, each displaying multiple disparate data types Multiple simultaneous animations in separate windows Imposition of isosurface and orthoslice representations on both a 2D image and a data-mapped 3D geometry Innovative data-presentation techniques to enhance end-user understanding

Key AVS/Express Modules Used

• rect_climate
  A combination of Express-standard modules including FPlane, bounds, advector, ReadImage, isosurface, combine_vect, and texture_mesh.


• sphere_climate
  A combination of Express-standard modules including isosurface, orthoslice, extract_scalar, and Read_Geom.


• Uviewer3D
  Standard Express module that defines all of the necessary components for the display portion of a graphics application.

Analogous Applications

• Medical Analysis - Multiviewer comparative analysis of patient data; orthoslice views.


• Plant-floor Operations - Simultaneous micro- and macro-views of a plant floor.


• Oil & Gas Exploration - Registration of multiple data sources; orthoslice views of volume data.

Instructions for use

1. Open the Climate demo by dragging its object from the library into the Application space.

   In AVS/Express, you begin building an application by finding the objects you need in the Libraries section of the Network Editor and then dragging them into the application workspace. This process is called instancing. When you instance an object, the AVS/Express Object Manager executes the functionality associated with that object.

   So in this case, where the Climate object represents a complete (albeit simple) application, instancing it causes it to execute the completed Climate application. To learn more about instancing objects, see AVS/Express Concepts, Getting Started with AVS/Express, Section 2.2 Instance Objects in the Network Editor.

2. In the application windows that open, notice the three main components:
   • The tallest, vertically oriented window, called Climate, holds a panel devoted to user interface controls, or Editors. At the top of this panel, note the drop-down menu labeled Modules, with Summary as the currently selected menu item and the other Modules that make up Climate also listed. Choosing a Module in this menu causes its controls to appear in the panel. For now, we'll leave Summary chosen because it provides a top-level user interface for the overall Climate demo. It does this by presenting the most important subset of controls for the Modules doing the real work. In that respect, this panel is a simple example of an application-specific UI that you might create.
   • The Scene#1 window is referred to as a DataViewer, which is where AVS/Express displays data and the end-user interacts with it. Scene#1 shows a sphere with color-mapped data as well as 3D data representations surrounding it.
   • The Scene window is a second DataViewer and has the same general interactive qualities as the Scene#1 window, but shows a wireframe box with a 2D image as a floor or backwall and both 3D and vector data representations overlaid.
3. Back in the Summary panel, do this:
• Click the Animate Wind checkbox so that it is checked. In the Scene window, the arrows representing wind vector data begin cycling through an animation sequence.
• Click the Animate Slices checkbox so that it is checked. In the Scene#1 window, the orthogonal slices representing latitudinal and longitudinal positions begin cycling through an animation sequence.

Interacting with Data in the Data Viewer

In the display area of either Scene window (Scene or Scene#1), click and drag with the left mouse button; the scene rotates. Releasing the mouse button while dragging causes the scene to rotate continuously until clicked.

Controls in the Individual Module Editors

The following section briefly covers the editors for the most important individual modules within the Climate demo.

1. Arrange the Scene#1 (sphere) window and the Climate (Editor) window so that you can see both of them.
2. In the Climate window, find the Modules drop-down menu and choose Modules -> Surface Component. The Surface Component Module Editor appears.

u, v and w refer to the mapping coordinates for a texture to the sphere: u is width, v is height, and w is depth. Choosing u, v or w maps the corresponding component of the velocity field (like an xyz value for each point that indicates direction) to affect the color mapping on the sphere. The humidity radio button causes humidity data to be mapped to the sphere's surface as ranges of color. The temperature radio button causes temperature data to be mapped to the sphere's surface as ranges of color.

Change the selection to humidity and observe the effect on the sphere display; change the selection back to temperature.

3. Use the Modules drop-down menu to choose Isosurface (Sphere). The Isosurface (Sphere) Editor appears.

   This module controls the data-mapping and scaling of the isosurface imposed around the sphere. The iso component radio buttons choose which type of data the isosurface's shape will represent; the iso slider has a unique range for each possible component. Click the "..." button to see the min and max values per component selection. If you change a value, press Enter to commit your change.

   Choose humidity for iso component and temperature for the map component, which controls the color-mapping of the isosurface. Then adjust the iso level slider to about 0.01. The iso slider determines the value to display for the chosen iso component: the resulting isosurface indicates the presence of that value. The temperature choice for map component colors the isosurface according to the temperature values at those same points.

   
   
4. Use the Modules drop-down menu to choose Animate Wind. The Animate Wind Editor appears.
   

This module controls the various attributes of the wind animation in the Scene (rectangle) window. The top set of sliders are used to control various aspects of the wind simulation. Think of the area over which the simulation occurs as a grid. N-segments, put briefly, specifies the number of steps used to calculate a cell's worth of movement; Max Segments sets the upper limit on that detail. Order further specifies the detail level of each calculation step. Minimum Velocity filters out particles based on their velocity. Direction controls the simulation direction. Under Mode, the main difference between Scalar and Vector is the directional quality of the resulting glyph. Components is more powerful when used with more-detailed glyphs than are shown here; it maps additional vector detail onto the glyph's scaling. Glyph Normalize and Scale adjust the size of the arrow representations, singly and relative to each other. The Start Time, End Time, Step and Release Interval sliders all control simulation attributes and can each be rescaled by clicking the "..." button.

5. Use the Modules drop-down menu to choose bounds. The bounds Editor appears.
   

This module is quite simple but demonstrates some important display capabilities. The combination of choices shown at the right yields the following scene by making certain sides of the bounding box not only visible but data-mapped:



6. Take a moment to look at each of the Read_* module Editors. Each one allows user specification of a file to be read into the application, whether for an image, a geometry, or a dataset to be used.
7. Choose Modules -> FPlane and adjust each slider slightly to the right. Note the increased density of data display in each dimension.

To exit the Climate application

If you wish to continue, skip to the next section and come back to these instructions when you are finished working.

• Exit the Climate application from the application itself by choosing File -> Exit.
• Exit AVS/Express by choosing File -> Exit from the AVS/Express Network Editor window.

Discussion of Key Modules

For this section, please switch to the Network Editor Window. The Network Editor looks like this:

You can view the sub-components of any module by double-clicking directly on it; close any opened module by double-clicking its title bar. You can see man-page style help on any module by right-clicking it and choosing Help from the resulting contextual menu.

Uviewer3D

Uviewer3D defines all of the necessary components for the display portion of a graphics application: a default graphics window like the ones in which you are viewing the Climate app, and a collection of user interface editors that you can use to control the display of these objects. Uviewer3D is fed information about the items it needs to render by rect_climate and sphere_climate, which are covered below.

sphere_climate

sphere_climate handles presentation of the climate data in the Sphere Scene window, available by choosing Windows -> Sphere scene. It does this by combining several AVS/Express-standard modules to cover various functions. FPlane generates a 3D plane of variable size that can be transformed in three dimensions, making it useful for sampling or slicing data before it is fed to another object. In this case, it is applied to the netCDF file brought in by Read_Rect_Data to produce the rectilinear representation of the weather data. isosurface creates a 3D isosurface representing the data type mapped to it, in this case the rectilinear field that was read in by Read_Rect_Data.The bounds module generates a bounding area for the rectangular climate display, with the various parameters and their effects already shown above. advector provides many of the controls seen in the Animate Wind module shown above; behind the scenes it places massless particles into the vector stream described by the actual wind data to create a visible representation of the wind's movement. combine_vect does exactly what its name indicates: it combines u, v and w into a node data vector to describe wind direction in this case. This enables the advector macro to construct particle paths through the vector field defined by this new node data vector.

rect_climate

rect_climate handles presentation of the climate data in the Rectilinear Scene window, available by choosing Windows -> Rectilinear Scene. It does this by combining several AVS/Express-standard modules to cover various functions: isosurface, which creates a 3D isosurface representing the data type mapped to it; orthoslice, which produces a cross-section of the data; extract_scalar, which pulls the data corresponding to a specified vector component of a field; and Read_Geom, which reads in a file representing the contour of the globe.

Discussion of Analogous Applications

Medical Analysis

The ability to view multiple scenes representing related data collections could be used to combine data from multiple patients for comparative purposes, various facets of a single patient's condition for correlative analysis, or educational applications for demonstrating relationships between multiple systems within the body, for example under changing conditions such as temperature or exertion.

Plant-floor Operations

Similarly to the medical example just described, the ability to view multiple related data sets could be used to examine behavior of multiple machines on the same plant floor under changing conditions, or to view multiple possible designs of an identically purposed piece of equipment for simulation-based comparative analysis.

Oil & Gas Exploration

Registration of seismic data and analysis of large-volume data are just two challenges related to oil & gas exploration that could be addressed in a custom AVS/Express application employing some of the same data processing and visualization techniques used in this Climate demo application. In particular, FPlane and orthoslice have clear uses for analyzing exploration data, and advector could be used in an application that simulates flow behavior around a given well.