Sample OPJ to download to try: Isometic Layer.opj
Graph layer can be set to isometric scaling so the axes will have the same length in pixels for the same scale range. When the layer is resized, the aspect ratio will be kept.
Thus for the above example, X axis spans from 0 to 100 and y axis spans from 0 to 50, isometric scaling will result in a layer with X axis twice the length of Y axis.
For 2D graphs, the control can be found in the Size/Speed tab at the Layer level of Plot Details dialog.The check box will be hidden when the scale is not linear.
For 3D graphs, the control is on the Axis tab at the Layer level of Plot Details dialog.