EnviroInsite provides the capacity to contour stratigraphy depth, elevation, and thickness. The contouring routines provide the same features as for the contouring of measured water levels or concentrations.
This tab allows the user to select the interpolation scheme and the parameters of the interpolation method. The correct selection of interpolation parameters is critical for generation of contours that accurately reflect the field data and our expectations of how the values vary between the measured data points. The default parameters are frequently adequate, although some improvement can be anticipated through trial and error.
The kriging routines are derived from the kt3d routine of the Geostatistical Software Library (GSLIB) authored by Clayton Deutsch and Andre Journel (www.gslib.com).
The reference, GSLIB: Geostatistical Software Library and Users' Guide is highly recommended. Here are the spherical semivariogram models used by EnviroInsite for an isotropic system, where h is the lag, c is the sill, and a is the (practical) range. This is from this link to an introductory text on kriging: Click here for an introductory text on the variogram models
For anisotropic systems h/a in the previous is calculated as
Virtual points are used to control the generation of contours with sparse data. In those cases, it may be advantageous to create virtual measurement points that will control the resulting contours.