The next two categories in the popup set the format and fixed point positions for each coordinate direction and, as they are identical, only setting the format and position of X is described here. The description for Y is identical save that ordinate is replaced by abscissa. The Date format requires that the axis be scaled with respect to the long form of the Julian date. The Degrees format is for latitude and longitude. Below the equator latitudes are negative.
Longitude is assumed positive east of Greenwich and negative to the west.