A radial internal table specifies location in terms of radius, and the data set must contain an identifier specifying that it is a radial table. It also needs a list of identifiers corresponding to the "columnar data" in the file. The columnar data must contain the radial coordinate as well as the scalar data. An example of the file format is given in Radial Internal Table File Format. It is represented in the object tree by a node that has properties and a pop-up menu.
The interpolation method for radial tabular data is a cubic spline. Hence, it is assumed that the radial data are sorted and single-valued.