How do I...?

IRIS Explorer IRIS Explorer

General Information

  1. How do I save my IRIS Explorer visualization as an image?
  2. How do I save my IRIS Explorer visualization as an animation?
  3. How do I save my IRIS Explorer visualization as a 3D scene?
  4. How do I save a camera position from the Render module?
  5. How do I add captions and titles to my IRIS Explorer visualization?
  6. How do I create and use a For loop in IRIS Explorer?

Visualization Techniques

  1. How do I subsample and crop my data in IRIS Explorer?
  2. How do I process images in IRIS Explorer?
  3. How do I display a two-dimensional array of heights in IRIS Explorer?
  4. How do I display a three-dimensional dataset in IRIS Explorer?
  5. How do I display flows, velocities and other vector-based data in IRIS Explorer?

General Information

How do I save my IRIS Explorer visualization as an image?

You can save any scene from the Render module as an image by wiring a button to Render's Snap port. Pressing the button causes the scene to be output from Render's Snapshot port. You can then view it using the DisplayImg module, or save it to a file using the WriteImg module.

Run ViewDemo with the snap.skm script file to see how it works.

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How do I save my IRIS Explorer visualization as an animation?

You can save any sequence of scenes from the Render module as an animation by wiring a slider to Render's Snap On Redraw port. Setting the slider to a non-zero value causes the scene to be output from Render's Snapshot port whenever it is changed. You can then save it to a file using the WriteMPG module.

Run ViewDemo with the redraw.skm script file to see how it works.

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How do I save my IRIS Explorer visualization as 3D scene?

You can save any part of the 3D scene displayed in the Render module to a file. To save all the geometry, use the Pick All option on Render's Edit menu. The geometry is output on Render's Picked Geometry port, where it can be saved to file using the WriteGeom module. Alternatively, individual parts of the scene can be saved by picking on them, or WriteGeom can be wired directly to the geometry module itself.

Run ViewDemo with the savescene.skm script file to see how it works.

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How do I save a camera position from the Render module?

The camera defines the view of the 3D scene displayed by the Render module. You can save it to a file by wiring the WriteGeom module to Render's Output Camera port. It can be restored using a ReadGeom module wired to Render's Input Camera port.

Run ViewDemo with the savecam.skm script file to see how it works.

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How do I add captions and titles to my IRIS Explorer visualization?

Visualizations can be enhanced by adding text, captions, titles or legends. These are passed into Render's Screen port, from which they are displayed in two-dimensional screen space, independent of the orientation of the camera.

Run ViewDemo with the screen.skm script file to illustrate this using the Legend module.

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How do I create and use a For loop in IRIS Explorer?

You can create a loop in an IRIS Explorer map which causes any parameter value to change from a starting value to an end value by a series of steps. This can be useful when creating an animation, or when trying out a range of parameter values. It is done using the For module.

Run ViewDemo with the forloop.skm script file to see how it works.

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Visualization Techniques

How do I subsample and crop my data in IRIS Explorer?

Sometimes it's necessary to reduce the amount of data which is to be visualized, either for reasons of performance or simplicity. In particular, you might want to only view every - say - fifth data value, or be only interested in a certain part of the data domain. This can be done using the SampleCrop module.

Run ViewDemo with the sampling.skm script file to see how it works.

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How do I process images in IRIS Explorer?

A variety of image processing techniques can be used to enhance or improve the contents of a two-dimensional image. These include edge-detection, blurring, Fourier transforms and color enhancement.

Run ViewDemo with the imaging.skm script file to illustrate the use of some of them.

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How do I display a two-dimensional array of heights in IRIS Explorer?

A two-dimensional array of topographic heights provides an example of a dataset where one variable (the height) is a function of two others (latitude and longitude). Other examples could include the temperature of a two-dimensional surface, or a mathematical function of two variables, f(x,y). In general, the two variables x and y are referred to as independent variables, while the third variable (f) is called the dependent variable. There are two classes of techniques in IRIS Explorer which can be used to display this type of data data:

  • contour-based, in which contour lines are drawn to connect together all places in the dataset having the same value for the dependent variable. This can be done by the Contour module;

    Run ViewDemo with the contour.skm script file to illustrate its use.

  • surface-based, in which a three-dimensional surface is constructed across the dataset. The height of the surface at each point is determined by the local value of the dependent variable. In addition, the surface could be coloured according to a second dependent variable (for example, snow depth over the terrain).

    Run ViewDemo with the surface.skm script file to show how to construct a surface from two-dimensional data in IRIS Explorer.

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How do I display a three-dimensional dataset in IRIS Explorer?

Some examples of a three-dimensional dataset include temperature in a room, atmospheric pressure in a three-dimensional chamber, or a mathematical function of three variables, f(x,y,z). In general, the three variables x, y and z are referred to as independent variables, while the third variable (f) is called the dependent variable. This type of dataset can be displayed by calculating an isosurface, which is a surface in three-dimensional space which passes through all points where the dependent variable has a given value (called the threshold value).

Run ViewDemo with the simple.skm script file to illustrate the calculation of an isosurface using the IsosurfaceLat module.

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How do I display flows, velocities and other vector-based data in IRIS Explorer?

Datasets which have a magnitude and direction at each coordinate are referred to as vector-based. Some examples are flow fields, velocity fields forces and other gradient data. There are two classes of techniques in IRIS Explorer which can be used to display vector-based data:

  • glyph-based, in which an icon or glyph (usually an arrow) is placed at each location in the field. The magnitude and direction of the field at the location is used to determine the size and orientation of the glyph. In IRIS Explorer, the VectorDisplay module can be used to generate this type of visualization.

    Run ViewDemo with the 3dvectors.skm script file to see how it works.

  • particle-tracing, in which weightless particles are released into the field at selected locations. The particles are then moved through the dataset, under the influence of the local value of the field, and the shape of their trajectories contains useful information about the dataset. The NAGAdvectSimple and NAGAdvectAnimate modules are used to generate particle tracing from vector-based data.

    Run ViewDemo with the 3dparticles.skm script file to see how they work.

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© The Numerical Algorithms Group Ltd, Oxford UK. 2001

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