Circle of a sphere the Equator the only great circle. By contrast, all meridians of longitude, paired with their opposite meridian in the other hemisphere, form great circles. The diameter of the sphere which passes through the center of the circle is called its axis and the endpoints of this diameter are called its poles. A circle of a sphere can also be defined as the set of points at a given angular distance from a given pole. When the intersection of a sphere and a plane is not empty or a single point, it is a circle. This can be seen as follows:
Science On a Sphere runs on Linux. SOS was invented by Alexander E. MacDonald, the former director of the National Oceanographic and Atmospheric Administration (NOAA) Earth System Research Laboratory in Boulder, CO, and OAR Deputy Assistant Administrator for the NOAA Research Laboratories and Cooperative Institutes. MacDonald devised the original idea for Science On a Sphere in 1995 as part of other data visualization work he oversaw in what was the former NOAA Forecast Systems Laboratory. A small but highly motivated and inventive team of NOAA staff led by chief designer David Himes wrote the SOS software and developed the SOS hardware and system architecture.