How Does Height Based Color Work?

Mapping Z Values to a Color

In order to map Z values to a color, we need to know what the range of z values are. There are several ways to set the range.

One method sets the range based on the current scale limits for the z axis. In this case, the grid settings would determine the limits.

Another way to determine the range of values, is to link the range to the maximum and minimum values in the data. When this option is chosen, and all of the data is plotted, then all possible colors in the color scheme are displayed.

Finally, there it is possible to link the range of possible values to an arbitrary values (which are user determined).

Color Schemes

A color scheme is a of generating colors, which defines two points, and an implied path to go from one point in a color space to another point. There are several schemes built into the 3D Data Visualizer. There are as many colors in a color scheme as supported by your computer's hardware.

PreDefined Color Schemes

Hues and Reverse Hues

This color scheme goes around the outer edge of the RGB color wheel, providing saturated colors. (The reverse scheme goes around the color wheel in the other direction) There is a small break in the color path for this scheme. Without this break in the path, the maximum and minimum values would map to nearly the same color.

Black to White and White to Black

This color scheme is actually devoid of color, and proceeds from black to white, using only gray values. The white to black scheme is naturally, the reverse.

Custom Colors

This color scheme obtains two points on the RGB color wheel, and traverses a straight line between the two colors.

Color Maps ...

A color map provides a slightly different way to choose colors for a particular value. Values are mapped to a discrete set of colors (given in the color map).

Color Map Inspector

The 3D Data Visualizer Pro includes a color map inspector. The inspector shows the red, green, and blue components of every color in the color map, as well as a color sample. There is also a graph which displays how the red, green, and blue color components vs the index. Predefined Color Maps Heat and Reverse Heat color map consists of 64 warm colors ranging from red to orange, to yellow. Cold and Reverse Cold maps contain 64 colors ranging from cyan to purple. The Fluid color map progresses from 64 colors which start and dark blue and progress through cyan, to light green, and then to yellow, orange, red, and finally dark red. Naturally, the reverse fluid, goes in the other direction. Hues and Reverse Hues provide 64 colors of saturated hue values.

User Defined Color Maps

It is actually quite easy to define your own color map. The color map itself consists of ASCII data in a table format. Each row defines a color. Each row has 3 columns (separated by commas) - one each for red, green, and blue. Red, green, and blue values are floating point values which range from 0.0 to 1.0. The number of rows determines the number of elements in the color map.

Here is an excerpt from a sample color map file :

0.000000, 0.000000, 0.500000
0.000000, 0.000000, 0.563492
0.000000, 0.000000, 0.626984