Differences in water flow rates for the Colorado River at Lees Ferry, Arizona are instantly recognized in Surfer using a time-series visualization technique developed by Dr. Richard Koehler, CEO of Visual Data Analytics. These patterns practically jump off the screen when viewing one of the temporal raster maps created by Koehler.
The USGS gauge serves as a valuable case study in identifying and analyzing flow. This point is tied to legally agreed upon volumes flow on the Colorado River basin. Lees Ferry is key to monitor the water flowing past this point, a resource vital to the economies of numerous western states.
Water flow is usually plotted on a 2D line graph with time on the X axis and flow rates on the Y. When many years are layered on each other, a ‘spaghetti plot’ is created where details are very difficult to see.
“The irony of line graphs is the more data you display, the less detail you see,” said Koehler, who presented the Lees Ferry case study in a recent Golden Software webinar.
Using Surfer, Koehler shows flow differently. By using “day of year” on the X axis and using “year” on the Y axis, he can represent specific dates by coloring each day. The results show high water flows as blue and low flows as red/orange colors. Suddenly, the magnitude, frequency, duration, timing and change of flows are easy to see. Deciphering patterns in large temporal datasets is challenging; however, with Dr. Koehler’s visualization technique, patterns that are difficult, if not impossible to see on a line plot are clear as day.