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Displays a dialog box that allows you to specify the size and number of intervals in a generated rectangular grid of 3D points based on the current 3D surface plot.
This routine uses one of two methods to generate Z values. Bivariate interpolation (in general) produces a smoother surface than what is typically displayed with randomly-spaced points. In many cases the resulting grid is a more accurate representation of the input than the triangular-mesh plot, but it should also be obvious to the user that no algorithm can make up for sparse data. Bivariate interpolation does not perform well on surfaces that include sudden changes in elevation. Planar interpolation simply maps each generated point to the planar surface of the triangle containing the point. The generated surface will not be as smooth as one produced by bivariate interpolation, but it does not have the same problems with rough surfaces.
Bivariate interpolation options
Extrapolate points outside convex hull
If checked, DPlot will generate values for the entire extents (specified with the from and to boxes). Depending on the complexity of the existing surface near the edges, these extrapolated values may be, at best, questionable. If this box is unchecked, values outside the limits of the triangular mesh are set to -1.E+38, which in turn causes DPlot to ignore them.
Control points
Number of additional data points used to estimate partial derivatives at the input points. In most cases the default value of 4 works nicely. However in some cases more points are needed to smooth the resulting plot.
The bivariate interpolation method uses the IDBVIP algorithm developed by H. Akima, available from the NETLIB Repository, http://netlib2.cs.utk.edu.
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Related macro commands |
Page url: http://www.dplot.com/help/index.htm?helpid_generate_mesh.htm
