Pitney Bowes MapInfo Vertical Mapper - Manual (Page 34)

Triangulation with Smoothing
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Vertical Mapper 3.7
The 5th Order Solution button enables you to apply a complex polynomial expression to the
calculation of each grid node value. The calculation is based on solving a number of slope
derivatives. The result is a more highly smoothed surface that displays minor angular artifacts from
the original TIN.
The Linear Solution button enables you to calculate the grid values directly from the TIN surface;
therefore, no derivative slope solution is applied. The result is a grid surface that exactly duplicates
the angular appearance of the TIN.
The Cell Size box enables you to set the cell size in real units. The value chosen should be a
compromise between the degree of resolution required for analysis and visualization purposes and
the processing time and file size. The default value is calculated by dividing the diagonal extent of
the point file by 500, which is considered an optimum number based on the average computing
power available.
The Weight Factor box enables you to define the degree of influence imposed by neighbouring
triangles in calculating a slope value for each triangulation point. Increasing the weighting factor will
increase the relative influence of more distant triangle faces and will result in a greater degree of
smoothing of the derived surface. Values range between one and 100.
The Exponent box enables you to set the variable that defines the exponential decay of influence of
neighbouring triangle faces the farther they lie from each point. Increasing the exponent will
decrease the relative influence of more distant triangles. Values range between one and 20.
Note The default values for the weight factor and the exponent are appropriate for most data.
However, you should experiment with various settings in order to evaluate which variable
generates the most appropriate representation of your data.
The Create MIF from TIN check box enables you to save the .tri file as a MapInfo format region file
(.mif). You can then view the triangulated surface in a Map window as a wireframe representation
using the Import command from the Table menu in MapInfo Professional.
The File name box enables you to enter a new file name for the .mif file.
The Extents button displays a summary of the geographic size and the z-value range of the original
point database, the density of the points, and the data value units.