Specifications

University of Pretoria etd – Combrinck, M (2006)
values. A final filter is applied keeping only values between -5 and 5S/m to grid and
contour. The contouring colour scheme is fixed for all sections and assigns dark blue to
all negative values and a logarithmic scale from light blue (0S/m) to magenta (5S/m) for
positive values. All negatives are grouped together as their presence can be used to help
identify confined conductors and show instances where the assumptions of the S-layer
differential transform were not completely satisfied, but there is little to be gained from
the actual numerical value of these negative conductivities. It is therefore preferable to
spread out the resolution of the colour contour scheme over the positive data range.
Conductor decay constant [s] (Draped over topography)
Imaged Conductivity [S/m] (Sections)
Figure 5-13: Contour map of conductor decay constants draped over topography and
conductivity depth sections in 3D. Top viewpoint is from inclination 20˚, declination 180˚ and
5km distance. Bottom viewpoint is inclination 10˚, declination -100˚ and distance 5km. Axes
are Northing, Easting and Elevation above sea level.
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