Pitney Bowes MapInfo Vertical Mapper - Manual (Page 57)

Chapter 4: Creating Grids Using Spatial Models
User Guide
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Setting the Number of Points
At each cell of the grid, the Location Profiler measures the distance to every point lying within the
search area and calculates the average value. However, the pattern of geographic centres
generated by the process will vary depending upon the number of points used for each grid cell
calculation. The number of points is determined by defining a search area around each grid cell to
select points, and defining the minimum and maximum number of points to be used for each
calculation.
The next two figures show the result of varying the number of points used by the Location Profiler for
each grid cell calculation. By default, the algorithm sets the search radius and the maximum number
of data points to include 100 percent of the points in the table. Using the default settings thereby
creates a grid that defines the most central region of the point location database.
This illustration shows the geographic profile of a table of point locations (represented
by black dots) calculated using 25 percent of the total number of points. Sites lying
within the more central contour regions are closer to the surrounding points than sites
lying within the outermost regions.
Reducing the number of points involved in each grid cell calculation, by decreasing both the search
radius and the maximum number of data points, tends to create a more complex profile that
highlights local zones of greater point density within the overall distribution of points. This may be
useful if, for example, you want to highlight local areas of greater site density across a geographic
area.