Acknowledgements

LineIntConv

• Displays (large) 2D vector lattices
• Convolves image along vector streamlines
• Uses LIC library of Cabral & Leedom (B. Cabral and C. Leedom, Proceedings of SIGGRAPH'93, 263-270)
• Choice of filters & normalisation
• Executes in parallel on multi-CPU's

Example: turbulent flow field

• Toy vector data - set of vortices
• Input vector lattice is 250 x 500 nodes
• Read in by Read2DV (from NAG)
• Input image is random lattice
• LineIntConv gives convolved image
• Contrast enhanced with HistNormImg

EditChan

• Edits component of multichannel lattice
• Useful for setting discrete colourmap e.g. alpha channel

      a(i) = a0,  0 <_ i < L1
             a1, L1 <_ i < L2
      etc
  

  User control over values and limits
• Written in the Shape language

Example: volume rendering

• Active site of Bovine SOD enzyme
• Electron density from X-ray data
• Input 3D lattice is 97 x 97 x 116 nodes
• EditChan sets opacity of colourmap
• Lattice displayed using
  • VolumeRender slicer algorithm
  • MultiSlice
  with same colourmap for each

NCSA PATHFINDER modules

• Suite developed for atmospheric data
• Support for
  • Hierarchical Data Format (HDF) files
  • Visualising vector data
  • Annotation & display
  • Lattice mathematics
• Pre-compiled or source available from here

Example: storm visualisation

• Numerical simulation of thunderstorm
• Data stored in HDF format (wind velocity, pressure, density, buoyancy...)
• Read using ReadDF
• VectorDisp used for wind velocity
• VolumeToGeom used for density
• Axis used for labelled axes (Written by Rob DeMillo and Oliver Newell, MIT Lincoln Laboratory, 1992)