Gas Production in Southwest Virginia
This figure of gas production in southwestern Virginia uses three different two-dimensional line graphs to compare coalbed methane production, conventional gas production, and total gas production over time. The independent variable time (in years) is plotted on the x-axis; the dependent variable gas production (in billions of cubic feet) is plotted on the y-axis. Graphing more than one two dimensional line graph in a figure is an effective method for highlighting comparisons between different categories of the same variable. One can easily see that coalbed methane production rapidly increased after 1991, and by 1994, yielded more cubic feet than conventional gas production (Ref ).
Copyright © 1998 Central Virginia Governor's School for Science and Technology Lynchburg, VA