A file with .igs (Initial Graphics Exchange) extension is a 2D-3D design exchange file format that is independent of source or destination file format specifications used by CAD applications. It is used to exchange design information about circuit diagrams, wireframes, the freeform surfaces between two independent systems. IGS files can be opened by applications such as Autodesk, FreeCAD, CADEX CAD Exchanger, and other similar applications.
Files with ODS extension stand for OpenDocument Spreadsheet Document format that is editable by the user. Data is stored inside the ODF file into rows and columns. It is an XML-based format and is one of the several subtypes in the Open Document Formats (ODF) family. The format is specified as part of the ODF 1.2 specifications published and maintained by OASIS.
You can also convert IGS into many other file formats. Please see the complete list below.