3.1 Java1489-plotting 3d surfaces using java  (Page 10/24)

Display = 3, 4, and 5

These values for the display parameter specify that the surface is to be plotted in the same format as for display values 1, 2, and 3, except that thesurface elevation values are rectified (made positive) and converted to log base 10 before being represented by a color and plotted.

A calibration scale

When the surface is plotted, a horizontal calibration scale is plotted immediately below the surface plot showing the colors used in the surface plot.The colors begin with the color for the lowest elevation at the left and progress to the color for the highest elevation at the right.

Normalization

Regardless of whether the surface elevation values are converted to log values or not, the surface values are normalized to cause them to extend from 0to 255 before converting the elevation values to color and plotting them. The lowest elevation ends up with a value of 0. The highest elevation ends up with avalue of 255.

For display value of 0 or 3

This is a Grayscale plot or a log Grayscale plot as shown at the left side of Figure 2 . The highest normalized elevation with a value of 255 is painted white. The lowest normalized elevation with a value of 0 is painted black. The surfaceis represented using shades of gray.

The shade changes from black to white in a uniform gradient as the normalized surface elevation values progress from 0 to 255.

For display value of 1 or 4

This is a Color Shift plot or log Color Shift plot as shown in the center of Figure 2 . The lowest normalized elevation is painted black and the highest normalized elevation is painted white. (Black and white overwrite blue and red for these two elevation values.)

The color changes from blue through aqua, green, and yellow to red in a smooth gradient as the normalized surface values progress from 1 to 254. (Valuesof 0 and 255 would be pure blue and pure red if they were not painted black and white.)

For a display value of 2 or 5

This is a Color Contour plot or log Color Contour plot as shown at the right side of Figure 2 . The highest normalized elevation with a value of 255 is painted white. The lowest normalized elevation with a value of 0 is paintedblack.

The surface is represented using a combination of unique shades of gray and unique colors as the normalized surface elevation values progress from 0 to 255.This is not a gradient display. Rather, the colors in this display change abruptly from one color to the next.

This display format is similar to a contour map where each distinct color traces out a constant elevation level on the normalized surface being plotted.

The main method

Although the class is intended to be used by other programs to display surfaces produced by those programs, the class has a main method making it possible to run it in a stand-alone mode for testing.

When the class is run as a stand-alone program, it produces and displays six individual surfaces with the lowest point in the upper left corner and thehighest point in the lower right corner. The six images produced by executing the main method are shown in Figure 3 .