GIS 6005 Lab 4: Working with Color

Color ramp	Notes	Stepwise Intervals
Linear progression		R20	G35	B27
	-Lightest color selected using approximately the same ratio of RGB as darkest -The RGB steps divided by 5 leads to R steps of 20, G steps of 35, and B steps of 27	20 20 20 20 20	35 35 35 35 35	27 27 27 27 27
Adjusted progression
	-Using the same dark and light colors of purple, the adjusted progression steps are based on the general rule (provided in lab text) that the darker color steps are a third higher than average and the lighter color steps are a third lower than the average.	27 24 20 16 13	47 40 35 29 24	36 32 27 23 17
ColorBrew
	-The steps provided by colorbrew created a more defined color progression with greater variations in the steps between each color.	69 2 -22 11 29	28 73 47 37 53	52 57 23 19 28

              

The differences between my linear and adjusted progression color ramps are subtle, but the increased step size between the darkest colors in the adjusted progression ramp does aid in differentiating them. The Color Brewer ramp, however, created a progression of individual colors that are more defined and easier to distinguish. The RGB values show that Color Brewer varied the steps between each color selection much more than the linear or progression ramps. For example, the step from the darkest purple to the next color is large for R and B but relatively small for G, but the step to the next color is tiny for R (2) and very large for G (73). The third step actually reduces the R value instead of increasing it. This reflects our text in showing how complicated the relationship is between RGB values when creating color ramps and how many options we have in creating our maps.