A 3 column data file with the first line an integer value with the number of points to follow. Binary format. - not defined as of this writing. X Y DX format. X Y DY format. X Y DX1 DX2 format.
Error bars bracket the datum.
Error bars are drawn to the right of the datum. Error bars are drawn to the left of the datum. Error bars bracket the datum, but reversed from case 1. X Y DY1 DY2 format. Error bars bracket the datum.