Pitney Bowes MapInfo Vertical Mapper - Manual (Page 37)

Chapter 3: Creating Grids Using Interpolation
User Guide
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As the exponent increases, the influence a data point has on the calculated grid node
decreases. In this example, the data point has the amount of influence indicated by A;
however, if the exponent is increased to two, the amount of influence B is dramatically
reduced.
The Minimum # of Points box enables you to define the minimum number of points per zone, and
the Maximum # of Points box enables you to define the maximum number of points per zone. This
refers to the minimum and maximum number of data points searched for and averaged to calculate
a single grid node value.
The three options that follow (Number of Zones, Zone Orientation, and Radius Multiplier) define the
manner in which data points are averaged for each estimated calculation. The Number of Zones
box enables you to define the number of equally sized partitions by which each search area may be
divided.
The search area divided into one, two, and three equal zones.
This may be useful if the data contains points that are clustered along a particular orientation such
as data collected along widely separated survey lines. An equal number of points are averaged from
each half, quadrant, or octant of the search area. In the majority of point files, the most appropriate
number of zones is one. You should choose more than one zone only if you are confident that the
data is clustered in a linear orientation.
The Zone Orientation box enables you to define unique orientation parameters in the creation of
search area zones, which is appropriate only if data points are preferentially clustered in linear
zones. This value is expressed in azimuth degrees.