Such a projection can be pictured as a finite number of (oriented) arcs in the plane, separated by the crossings of the projection.

There is another reason: Air traffic control's main function is to keep planes safely separated, which is essential for jets flying at hundreds of miles an hour.

In Buddhism, the world is made up of 31 planes of existence that one can be reborn into, separated into 3 realms.

We had two big planes separated by twenty miles, and seven people to begin the investigation.

X-ray analysis shows D molecular symmetry with the aromatic planes separated by 262 pm.

Under these rules, pilots use their eyesight to keep planes safely separated, rather than depending on ground controllers using radarscopes.

Safety groups said the study underscored the need for better runway markings and new radar to keep planes safely separated.

Here, primary reliance is put on pilots' eyesight rather than on controllers at radar scopes to keep planes safely separated.

The constellation will be situated in a low Earth orbit and the satellites will travel on 6 orbital planes separated by 30 degrees of longitude.

On it distant mountains could be seen across a wide plane, separated from the viewer by valleys and rivers in between.