Software Overview:
Visualization

[Introduction] [Visualization] [Interface]
[Data] [Download WorldWatcher]

Interpretive Visualization

WorldWatcher provides many of the display features of visualization environments designed for scientific researchers. It displays two-dimensional global data in the form of color maps. To provide geographical context, it displays them with latitude and longitude markings and an optional continent outline overlay (Figure 1). A constantly updating readout follows the user's mouse as it travels over an image, displaying the current latitude, longitude, country or state/province, and data value. Users customize their scientific visualizations by modifying the color scheme, the mapping of colors to numerical values, the spatial resolution, and the magnification. They can also choose to display units in either metric or alternative systems. WorldWatcher provides statistical summaries for entire maps and for user-selected regions. Regions can be selected using rectangular and irregular region selection tools, as well as by specifying geographic areas by name (e.g., China), or data values by range (e.g., all areas with temperatures above 32 degrees F.).

Figure 1. A WorldWatcher Visualization window.

Analytic Visualization

In addition to the statistical summaries described above, WorldWatcher provides a number of functions for the mathematical analysis of data. WorldWatcher supports the quantization of an image, i.e., the transformation of the full range of input data values into a small number of discrete values. It also supports both unary and binary mathematical operations on the data. Within an image, users can add, subtract, multiply, or divide all the values in a region or an entire image by a constant. They can also normalize the values in an image, and using the blackbody equation convert energy values to temperature and temperature values to energy. Binary operations enable users to apply a function at each location in two images. The binary operators in WorldWatcher are addition, subtraction, multiplication, division, maximum, minimum, and correlation. The result is displayed in the form of a new visualization.

Figure 2. Binary math operations in WorldWatcher

Expressive and Constructive Visualization

Some of the most powerful learning activities that we have observed students engage in with scientific visualization technologies are those in which they use representational media to express themselves and construct hypothetical scenarios. WorldWatcher enables students to use scientific visualizations as expressions of their beliefs and hypotheses in three ways. One is through the customization of the display of visualizations using the features for changing resolution, color schemes, and magnification described under interpretive visualization. The second is through the mathematical creation of new data using the techniques for analytical visualization described above or using the model described below. The third is through a direct manipulation interface using a paint metaphor. The WorldWatcher paint interface allows the user to "draw" new data values on a visualization using a paintbrush tool for painting pixel by pixel or a paint can tool for filling regions. Users specify the data values to paint by typing in a value or by using an eyedropper tool to select values from an image or its color scheme.

Figure 3. The WorldWatcher tool bar.

The eyedropper tools toward the left enable users to specify data values to paint. The paintbrush and paint can tools are used to "paint" new data values in a visualization. Students have used the expressive capabilities of WorldWatcher to represent the state of their understanding (e.g., prior conceptions) and to create hypothetical scenarios. Student-drawn visualizations can be used as input to the WorldWatcher model that calculates new energy balance data sets.

WorldWatcher Globebuilder

The GlobeBuilder program was inspired by the HyperGami program developed by Michael Eisenberg at the University of Colorado. GlobeBuilder will turn any WorldWatcher colormap into a cut-and-fold diagram that can be printed and assembled into a 3-d polyhedron representing the earth (Figure 4). GlobeBuilder can generate three different polyhedra: a cube, a middle crystal, and an icosohedron. The resulting approximations of a sphere can serve as powerful learning tools for understanding map projections, the relationship between the earth and sun, and the seasons

Figure 4. A reduced cut-and-fold diagram of surface

temperature created by the WorldWatcher GlobeBuilder application. This figure can be cut out and folded into a "middle crystal" polyhedron consisting fourteen square and triangular faces.

[Introduction] [Visualization] [Interface]
[Data] [Download WorldWatcher]