Pitney Bowes MapInfo Vertical Mapper - Manual (Page 113)

Chapter 6: Working with Grids
User Guide
111
Hiding or Showing the Legend
• Position the cursor over a grid histogram, a cross section graph, or a point-to-point solution
graph, right-click and choose the Hide Legend or Show Legend command.
Smoothing a Grid
The Vertical Mapper Smoothing feature reduces the variability in a numeric grid by averaging cell
values contained in a specific area. In general there are two categories of filters. The first category
includes low pass (averaging) filters used for smoothing the variation of cell values found in a grid.
The second category consist of edge detection or high pass filters, these are typically used for
enhancing edges in grids and images. The new Vertical Mapper Smoothing feature uses the first
category of these filters.
What is Smoothing?
Smoothing is the act of filtering a grid by modifying the values of every cell in a numeric grid to be the
average of it's neighboring cells. This averages out the data in the grid to provide a more high-level
or relative representation of the data, thus removing any ‘noise’ from contours created from grid data
and reducing the size of those contour files.
The basic principal of averaging filters is to pass a window (3x3 or 5x5 cells) through the grid,
calculating the average value of all pixels inside the window and assigning this value to the central
cell in the window. The size of the window has an impact on the results; a greater degree of
smoothing will result when using a larger window size.
Using the Smoother Utility
The Smoother utility only works on numeric grid data. With at least one numeric grid file open, click
Smoother from the Vertical Mapper menu within MapInfo Professional. The Smoother dialog box
displays.
Use the Input Grid drop-down list to choose a grid file to smooth from a list of all opened numeric
grids.