Cartesian Coordinate Graphs:

The most general type of graph using the Cartesian coordinate system is one in that all values of both the x-coordinate and the y-coordinate are positive.  That corresponds to Quadrant I of a Cartesian coordinate graph.  The relationship among two physical quantities is frequent display on this type of rectangular plot. The x-axis & the y-axis have to first be labelled to correspond to one of the physical quantities. The units of measurement along every axis must also be established.  For instance, to show the relationship among reactor power level and time, the x-axis could be used for time in minutes and the y-axis for the reactor power level as a percentage of full power level. Data points are plotted using the related values of the two physical quantities.