Within the Curve Combination Analysis, the user must define the best fit curve graphically. When the Graphical tab is selected, the editor will display a plot and table as shown in Figure 1. A minimum of three points are required to define a graphical frequency curve. In the plot, the frequency curves defined on the Frequency Curves tab will be plotted. The table to the right of the plot allows the user to manually enter data values for the frequency ordinates defined on the General tab.
Additionally, the Multi-Point Edit tool (Figure 2) can be used to define the frequency ordinates by drawing a curve. To use this tool, begin by selecting the tool on the left side of the editor. Then, define the curve by left clicking within the plot window at the desired locations. To finish defining the curve, right click. It should be noted that the Multi-Point Edit tool will not extrapolate frequency information; it will only interpolate to the user-defined frequency ordinates specified on the General tab. Bold, dashed lines will be displayed on the plot that correspond to the output frequency ordinates defined on the General tab. These vertical lines help to visually identify the locations where frequency information will be extracted from the drawn curve.
