A method graphically presents a selected group of data values of a series of data values in a predetermined presentation area. The largest data value within the selected group of data values is determined. A scaling factor for the determined largest data value to correspond with a lateral dimension of the presentation area is determined. The determined scaling factor is applied to all the data values in the group of data values. The scaled group of data values within the presentation area is graphically presented. Advantageously, the graphical presentation of the data values is scaled according to the data presented in the presentation area, thus maximizing the detail shown in the graphical representation. The method is preferably implemented in the form of a computer program.