The coordinate system of the Chart control is relative. Using relative
coordinates ensures that chart objects remain relative to one another when the
chart is resized, making positioning and sizing easier.
The coordinate system has its origin in the upper-left corner with the X axis pointing to the right and the Y axis pointing down (see the figure below). For 3D charts the direction of the Z axis is outward (going out of the page).
Coordinates are always expressed as a percentage of the element they are being applied to.
The coordinate system is applied to two types of objects:
Coordinate values are measured as a percentage of the chart picture's width and height. The top-left corner has the coordinates (0,0), and the bottom-right corner has the coordinates (100,100).
The chart picture's coordinate system determines the position of chart area objects and legend objects (if the legends are not displayed within a chart area).
Coordinate values are measured as a percentage of the chart area's width and height. The top-left corner has the coordinates (0,0), and the bottom-right corner has the coordinates (100,100).
A chart area's coordinate system determines the position of all objects contained within it, such as labels and annotations.