Straight lines can be drawn on Graph Reports as best-fit lines through some data set. This can be data from the project database, or an explicit set defined in the report properties.A straight line can be drawn or developed to fit to specified values by specifying a best-fit line as part of the report properties. Best-fit lines drawn in this way can have output conditions applied so that they will not be printed unless the output conditions are met.Sometimes you don’t want the line itself, but some aspect of the line data. These are generated whether or not the best-fit line is actually rendered on the report, and can be accessed using System Data Items. For example, the best-fit line slope angle returns the value of an angle whose tangent equals the slope of the line, while theline intercept returns the intercept of the line through one of the graph axes, depending on the best-fit line options that are selected. Best fit lines plotted against the Independent axis return the intercept value through the Dependent axis and the slope is calculated as the change in the Independent data over the Dependent data. If the best fit is calculated against the Dependent axis, the intercept is the value through the Independent axis and the slope is calculated as the change in the Dependent data over the Independent data.