Pitney Bowes MapInfo Vertical Mapper - Manual (Page 77)

Chapter 5: Creating Grids Using Other Methods
User Guide
75
Exploring the Point Density Dialog Box
The Cell Size box enables you to specify the cell size in the coordinate unit of the point file to be
processed.
The Search Area box enables you to specify the area around each cell to search for events. Units
are specified in the coordinate units of the point file to be processed.
Creating a Square Area Point Density Grid
1. From the Vertical Mapper menu, choose the Create Grid, Point Density, Square Area
command.
2. From the Select Table to Grid list, choose the table you want to create a grid from.
3. In the Select Event Sum Column list, do one of the following:
• If you want to count the points found inside the search area, choose Count Points Only.
• If you want to sum the values contained in a given field in the database, choose the name of
the column in the database that contains the values.
4. Click the Next button.
5. In the Point Density dialog box, enter the cell size and search area.
6. Click the Finish button.
Point Density Using Kernel Smoothing
The Kernel Smoothing method enables you to take a set of discrete points, such as specified
locations of crime or disease, and transform them into a continuous surface. These discrete points
are known as “events”. By studying the events occurring within a specified radius, you can
determine the probability of the event occurring in adjacent regions.
You can use two different variations of the Kernel Smoothing technique: weighted or classic. In the
weighted variation, you can apply a weight to a point in order to reflect the occurrence of multiple
events at a location. In the classic variation, all points are seen as single events and have the same
weight.