A PTM file is a map file used by the MapPoint mapping software developed by Microsoft which is discontinued by now. It contains maps data extracted from Microsoft’s Terra Server. The maps information contains data related to business travel routes and territories. MapPoint was later replaced by Bing maps. Other files used in conjunction with PTM files include MPP (MapPoint Map), WPT (MapPoint Waypoint), and RTE (MapPoint Route).
PTM File Format
PTM filed format is a proprietary file format and the internal file structure of .ptm files is not publicly documented.