Definition

A system of COOR­DINATES in a HORIZONTAL PLANE used to describe the POSITIONS of points with respect to an arbitrary ORIGIN by means of two distances perpendicular to each other. The two REFERENCE LINES at right angles to each other passing through the ORIGIN are called the coordinate axes. The distances parallel to the true (or arbitrarily assigned) north-south axis are called the ordinates, or the y coordinates. The distances parallel to the true (or arbitrarily assigned) east-west axis are called the abscissae,or the x coordinates. The north and east directions are usually taken as positive, and the south and west directions are usually taken as negative. Also referred to as plane coordinates.