CGPS Visualisation Software Information

Please send questions and comments to Richard Gooch.

Overview

Though several software packages are available for the examination of 3-D scientific datasets, Karma was selected for CGPS data visualisation by the CGPS consortium membership at its 2nd annual meeting. This decision was made for a variety of reasons, including functionality, flexibility, expansibility, and developmental access. The latter two were significantly augmented by the hire of Richard Gooch, the principal author of Karma, to carry out further software development for the CGPS consortium at the University of Calgary in 1999. Richard has since moved on to other opportunities, but he continues to develop Karma's capabilities actively.

Karma is not just for use by CGPS scientists, but by anyone with a need to visualise 2-D and 3-D datasets, astronomical or otherwise. It has a worldwide user base, and is available free of charge.

Useful Links

Karma Documentation , including online manuals for users as well as programmers. If you already have Karma installed on your own machine under the /usr/local directory, these same files are accessible under file:///usr/local/karma/www/doc.html.
Karma FTP Site with download and installation instructions.
Karma Home Page . A mirror site is maintained at the Radio Astronomy Group, Department of Physics and Astronomy, The University of Calgary.

Summary of Features

Two basic ways to examine a three-dimensional image are by looking at one or more 2-D slices through the data in various ways, or by studying the 3-D image as a whole with rendering techniques. The latter method can be quite demanding computationally, but sometimes it is the only way to discover features in the data which would otherwise remain hidden. The primary features of various ``modules'', or self-contained programs, of the different visualisation packages are listed below, with the modules sorted by technique and package.

2-D slices
- kvis
  - Animate/manipulate 1 slice (XY, YZ, or XZ)
  - Overlay contours or blink between multiple images
  - Extract point spectra along X, Y, or Z
  - Read-time data subset (subcube and block-average) extraction
  - Cursor sky & velocity coordinate tracking
  - Axis labels / coordinate grids
  - Image magnification, subregion zoom
  - Linear/log/sqrt true/pseudocolour images, contrast control
  - Read FITS/Miriad/GIPSY/karma
  - Write FITS/Miriad/GIPSY/karma/PPM/SunRaster/PostScript
- kslice_3d
  - Manipulate 3 slices (XY, YZ, and XZ) simultaneously
  - Read-time data subset (subcube and block-average) extraction
  - Cursor sky & velocity coordinate tracking
  - Image magnification
  - Pseudocolour images
  - Read FITS/Miriad/GIPSY/karma
  - No output capability
- kpvslice
  - Show arbitrary position-velocity slices (those _|_ to the XY plane)
  - Many other features similar to kview
- kshell
  - Generate radius-velocity map from annular integrals taken in steps outward from a fixed point to a given radius in order to identify expanding shell structures
  - Many other features similar to kview
- krenzo
  - Overlay a single contour of a specified isophote from many velocity channel maps onto a single image, colouring each contour differently to indicate its associated channel
  - Many other features similar to kview
3-D rendering
- xray
  - Voxel-sum, min/max voxel, hot gas, and substance rendering
  - Animate rotation of rendered volume
  - Track 3-D cursor with 3 simultaneous slices (XY, YZ, and XZ)
  - Adaptive filter techniques to pick features out of ``fog'' of noise
  - Colour tables, magnification, zooming
  - Stereoscopic projection (special hardware required)
  - Read-time data subset (subcube and block-average) extraction
  - Read FITS/Miriad/GIPSY/karma
  - Write FITS/Miriad/GIPSY/karma/PPM/SunRaster/PostScript

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