Not really a projection, but the graphical figure obtained by plotting latitude and longitude degree coordinates as if they were Y and X coordinates. The default "unprojection," it is also known as the geographical latitude / longitude projection.
Note that one latitude / longitude projection may be different from another because each such projection assumes that a particular datum is in use. While the WGS84 datum is almost universally assumed to the datum used, it is possible that some person assumed a different datum.
It is also possible to re-project latitude / longitude data into different datums, even including datums that include rotation factors. In such cases Manifold will faithfully reproject the data as direct taking into account datum rotation factors if applicable.
True in degrees along the Equator or vertically along any meridian.
Considerable distortion away from the Equator due to horizontal increase in longitude degrees.
Used to save digital maps in unprojected form using some assumed datum.