The GTGTechXml2Gtg.exe utility is a command-line tool
for converting one or more GTech Redline XML files to a GTViewer GTG file.
The utility uses a parameter file to provide information necessary for the conversion (this mostly comes from your data's GTM file). The input can be a specific XML file or a wildcarded (* or ?) path to specify a set of files to convert. The output is a single GTG file.
The GTGTechXml2GTG utility will be part of GTData, but it is available now (contact support to get it).