Pitney Bowes MapInfo Vertical Mapper - Manual (Page 101)

Chapter 6: Working with Grids
User Guide
99
Any numeric grid file generated in Vertical Mapper, using interpolation or modeling, is automatically
assigned a default colour palette that is applied when the file is first opened.
Colour is assigned to a numeric grid file according to ranges of grid values. Assume that a grid
consists of values from zero to 100. Discrete colour gradients are then assigned by range according
to defined inflection points. For example, the range from zero to 25 would be assigned colours
varying from dark blue for the lowest value to medium blue for the highest value, while the range
from 26 to 50 would be assigned colours varying from medium blue for the lowest value through
green to yellow for the highest value in the range, and so forth. This technique is a standard method
of presenting quantitative data in a continuous gridded surface using a gradient colour model, where
blue is commonly used to represent low or “cold” values, and red is commonly used to represent
high or “hot” values.
In addition to assigning colour gradients to numeric grids, you can also apply variations in light and
shadow. Relief shading is an effective visualization process that creates 3D-like images from a
continuous grid surface. The procedure calculates light and shadow effects based upon the angle of
incidence of an imaginary point source of light to create grey-scale or colour images.
Vertical Mapper also supports the generation of true 3D perspective views using GridView. This tool
gives you the ability to compose a Map window of any vector, raster, or textual entity that coincides
with the spatial extents of the grid file and then drape the window onto a 3D representation of the
grid surface. Perspective 3D rendering is supported in Vertical Mapper through implementation of
the OpenGL graphics language.
In assigning colour to classified grids, Vertical Mapper uses a separate function called the Dictionary
Editor. Using this tool, you can assign unique colours to each category of grid cells.
Using the Grid Colour Tool for Numeric Grids
All the display and colour options available for numeric grid files are contained in the Grid Colour
Tool. The settings available in the Grid Colour Tool allow extremely precise control of gradient colour
spread across the range of values found in the grid file. Discrete colour gradients are assigned by
range according to defined inflection points. The Grid Colour Tool enables you to place up to 64
inflection points. A histogram showing the distribution of values in the grid file is displayed in the Grid
Colour Tool window to assist in the placement of colour inflection points.