Some of the real-life uses of polar coordinates include avoiding collisions between vessels and other ships or natural obstructions, guiding industrial robots in various production applications and calculating groundwater flow in radially symmetric wells. Polar coordinates can also be used to determine the best audio pickup patterns for cardioid microphones. Calculations involving aircraft navigation, gravitational fields and radio antennae are additional applications in which polar coordinates are used.
Like the Cartesian x- and y-axis system, polar coordinates exist within a two-dimensional plane. The points on the plane are determined by both their angle and distance from a fixed point, which is called a pole. The distance from the pole is called the radius or radial coordinate. The fixed-direction ray originating at the pole is the polar axis. The angle is referred to as the azimuth, polar angle or angular coordinate.