3.1 Java1489-plotting 3d surfaces using java  (Page 6/24)

More minor peaks

This plotting format also exposes four more minor peaks at the corners of the plot. The light gray color indicates that the level of these peaks is about twolevels up from the lowest elevation. These four peaks are barely visible in the Color Shift plot in the center, and their elevation is clearly not quantifiablein that plotting format. They are not visible at all in the Grayscale plot on the left end of Figure 1 .

The design of this program

There are numerous options available when designing a Color Contour Plotting program. As mentioned above, the Color Contour plotting format in this programsubdivides the surface into 23 elevation levels including the lowest and the highest levels. Then it represents each elevation level with a different coloror shade of gray. This causes a lot of quantitative information to become available that isn't available with either of the other two formats.

(There is nothing unique about 23 elevation levels and 23 colors. It would be very easy to use many more levels and many more colors. The biggestdifficulty when designing the Color Contour format is identifying a large number of colors that are clearly identifiable both on the calibration scaleand on the surface plot. This raises the question as to how many unique colors a human can discern. Theoretically, a computer program such as thiscan generate more than sixteen million different colors. Obviously, a human cannot discern sixteen million unique colors.)

Good quantitative elevation information is available

To determine the elevation associated with a particular color, all you need to do is to locate that color on the calibration scale and determine itsposition relative to the colors at the ends. That will tell you the elevation associated with that color relative to the highest elevation and the lowestelevation. For example, the color at the exact center of the calibration scale represents an elevation that is half way between the lowest elevation and thehighest elevation.

(With this program, there are no absolute elevations. Rather, the calibration scale indicates each elevation level as a percentage of thedifference between the lowest and the highest elevations.)

The elevations of the minor peaks

Once again, this image shows that the elevations of the four minor peaks on the edges match the color aqua on the calibration scale. Judging from theposition of the color aqua on the calibration scale, the elevation of each of the four minor peaks is about thirty-five percent of the elevation of the majorpeak in the center.

This information is clearly not available from the Grayscale plot. It is also not available with this degree of accuracy from the Color Shift plot.

(All that we can tell from the Color Shift plot is that the minor peaks are some shade of green, which represents a rather large range of possibleelevations.)

The lowest elevations

The Color Shift plot does a better job of identifying the locations of the lowest elevations than does the Color Contour plot. This is because the colorblack was dedicated to that purpose in the Color Shift plot, but was used to represent a range of elevations in the Color Contour plot.