SAS/SPECTRAVIEW Software User's Guide

Setting Response Value Ranges and Colors

To set response value ranges and assign specific colors to those ranges, you use the data ramp. The software then uses the specified colors to display response values in cutting planes, point clouds, the response legend, the response histogram, and so on.

For example, if the response values are sales data, you could color the low values in red, the medium values in yellow, and the high values in green, then visually analyze the data to spot trends and relationships not evident in standard reports and graphs.

Understanding the Response Value Ranges and Colors

Located below the text window, the software provides data buttons and color buttons:

The data buttons display data values and allow you to interpolate between ranges of response values. You cannot change the values displayed on the data buttons. Turning a button on (selected) or off (deselected) changes how colors are interpolated between two selected buttons.
The color buttons display colors associated with the data values and allow you to assign specific colors to defined ranges.

In the default data ramp, each selected data button represents the lower bound of a response value range. The range is bounded above by the value on the next selected data button (exclusive of that value itself). The software interpolates (ramps) colors between selected data buttons. For example,

Deselect all data buttons except the top and bottom ones (which you cannot deselect).
Assign black to the top color button by clicking the top color button then using the color chips or sliders to assign 0, 0, 0 to the RGB values.
Assign white to the bottom color button by clicking the bottom color button then using the color chips or sliders to assign 100, 100, 100 to the RGB values.

The software uses the colors assigned to the top and bottom buttons to ramp intervening colors, as shown in Ramped Colors Between Top and Bottom Data Buttons. All intervening values are assigned gradations between black and white, that is, a gray-scale ramp. Similarly, response values in a resulting image, such as a point cloud or a cutting plane, display in black to white gradations.

Ramped Colors Between Top and Bottom Data Buttons

[IMAGE]

If you then select the color button in the middle of the top and bottom color buttons and assign it a third color (for example, yellow), the software ramps the colors between black (top) and yellow, and also between the yellow and white (bottom). All the response values falling above the middle button are displayed in colors ramped from black to yellow, and all response values falling below the middle button are displayed in colors ramped from yellow to white.

If you select multiple intervening color buttons and assign various colors, the software ramps the colors between each pair of selected buttons and displays response values within that range in the colors assigned.

Specifying Response Value Ranges and Colors

To define response value ranges and color:

Select [Palette].
Select [Data ramp], which is the default selection. The software displays RGB sliders, color chips, and the default data ramp, which has preset, evenly spaced ranges.

Determine the level of granularity by selecting:

[8 colors]	to divide the values in the data ramp into 8 segments and colors.
[16 colors]	to divide the values in the data ramp into 16 segments and colors.
[32 colors]	to divide the values in the data ramp into 32 segments and colors. This is the default.

The software creates the color data ramp by determining the range of the response values in your data set, then dividing that range into 8, 16, or 32 equal parts. Even though you can modify the response value ranges so that the 32-color data ramp uses only eight colors, selecting the 8-color data ramp instead has the benefit of uncluttering line contours.

To define a response value range use the data ramp:
1. Select the color button next to the data button that displays the lower bound value of the range. (When you select a color button, the data button is also selected.)
2. Specify a color for the range by using the RGB sliders or by clicking a color chip.
Note that to widen a range, you can deselect a data button. Once deselected, the associated color and those above and below it ramp as part of the surrounding range.
Repeat for each response value range.

Chapter Contents
Previous
Next
Top of Page