Notes on image production

These images have been created form a variety of Digital Elevation Models (DEM's), mainly using IDL and ENVI, but alos PovRay and Wlbur.

Images are given three labels as in : "Palmer : surf : DENR". The first (hyperlinked) part gives the general location of the image, the second part describes the image type while the third references the DEM datasource.

Images types inlcude

  1. "rast" -> raster or density images where colour mapping is propotional to elevation, eg; Indus : rast : GTOP.
  2. "shade" -> artificial illumination of the DEM is employed to highlight specific topographic features, eg; SulimanLobe : shade : GTOP.
  3. "surf" -> perspective view of the DEM draped with a "shaded" image, eg; Palmer : surf : DENR.
  4. "rnet" ->various DEM images overlayed by a rivernet work, eg, MtLoftyRanges : rnet : DENR.

The DEM sources are given by the following acronyms :

  1. ETOP -> ETOPO5 ; a 5' dataset which includes ocean bathymetry
  2. GTOP -> GTOPO30; A 30" dataset
  3. AGSO -> the Australian Geological Survey 9" DEM,
  4. DENR -> South Australian Department of Environment and Natural Resources 100 m
  5. MESA -> Elevations from the Mines and Energy South Australia gravity database gridded to ~3.5 km. SAND -> Sandwell and Smith 2' geosat derived topography

Production of the "shade" and "surf" images involve combinations of "derivative" images and density images on various RGB colour channels. For example the "Palmer : surf : DENR" image uses a 1st vertical derivative image on onechannel, a gradient image on a second channel and a raster image on the third channel.

River networks images have been produced using Scott Peckham's RiverTools.