XDF_018.xsd - eXtensible Data Format - version 0.18 Date: May 3, 2002 XML lanaguage schema definition. An XDF document contains arrays and data structures. It is designed to be both an interchange format for scientific data and to be of archival quality. Multidimensional tables and scalar or vector fields are represented in a consistent way and become self describing. Axial information can be included so that the space in which the data reside is fully described. Thus, XDF provides a consistent way to hold spectra with their wavelength scales, images with coordinate axes, vector fields with unitDirection, data cubes in complicated spaces, tables with complex column headers, and series of table sections with each section having a unique name.