A GMP file is a file that uses the `.gmp` extension, but the meaning of that extension depends on the software that created it. The most common meaning is a Global Mapper Package File, which is used by Global Mapper, a GIS and mapping program. In this case, a `.gmp` file is a self-contained map package that can include the actual map data, not just links to other files. It may contain raster data such as satellite images, aerial photos, or scanned maps; vector data such as roads, property boundaries, routes, points, and polygons; elevation data such as terrain models and contour information; and map settings such as labels, colors, styles, and coordinate system information.A Global Mapper `.gmp` file is useful because map projects often depend on many separate files. For example, a survey or land mapping project may include an aerial image, parcel boundaries, road lines, elevation data, GPS points, and labels. If someone only sends a normal workspace file, the project may not open correctly if the original source files are missing. GMP file opene `.gmp` package solves this by bundling the needed data into one file, making it easier to share, transfer to another computer, or keep as a backup. This is why `.gmp` files are commonly used by surveyors, engineers, GIS specialists, planners, and people working with property maps, GPS data, terrain, or geographic boundaries.The main difference between a `.gmp` file and a `.gmw` file is that a `.gmw` file is usually a Global Mapper Workspace file, which mostly stores project settings and references to external data files. A `.gmp` file, on the other hand, includes the actual map data inside the package. In simple terms, a `.gmw` file remembers the project setup, while a `.gmp` file carries the project data with it. This makes the `.gmp` format better for sending a complete map project to another person.When opened in Global Mapper, a `.gmp` file may appear as a layered map project rather than a single flat image. You may be able to turn layers on and off, inspect coordinates, measure distances or areas, check elevations, edit vector features, and export the data into other formats. If you need to use the data outside Global Mapper, the file usually has to be opened in Global Mapper first and then exported to a more common format such as KML/KMZ for Google Earth, SHP for GIS software, DXF/DWG for CAD programs, GeoTIFF for map imagery, CSV for coordinate points, or PDF if you only need a printable map.However, not every `.gmp` file is a Global Mapper file. The same extension can be used by other programs. A `.gmp` file can also be a Grand Theft Auto 2 map file, especially if it came from an old game or modding folder. It may also be related to Garmin GPS map data, especially if it came from a Garmin, OpenStreetMap, or navigation-related folder. Some sources also associate `.gmp` files with GUEmap, Geomorph tile maps, or GroupMail-related data. Because of this, the file’s source is very important.To identify what kind of `.gmp` file you have, check where it came from, the folder it is stored in, the file name, and the files around it. If it came from a surveyor, engineer, mapper, land project, GPS work, or a folder with files like `.shp`, `.kml`, `.tif`, `.dem`, `.dxf`, `.csv`, or `.gmw`, it is probably a Global Mapper or GIS-related file. If it came from a game folder and is near files like `.sty`, `.scr`, `.gxt`, or `.mis`, it may be a GTA2 map file. If it came from a Garmin or GPS folder and is near files like `.img`, `.tdb`, `.typ`, or `.mdr`, it may be Garmin map data.You can also check the file size and Windows Properties. A very small `.gmp` file may be a settings, index, or simple map file, while a large `.gmp` file may contain real map data such as imagery or elevation layers. In Windows, right-click the file, choose Properties, and check the location, size, date created, and the program listed under “Opens with.” If Windows does not recognize it, that does not mean the file is damaged; it only means the correct program may not be installed.You can open a copy of the file in Notepad or Notepad++ to look for clues, but you should not edit or save it. Some files may show readable words like “Global Mapper,” “Garmin,” or “GTA,” but many `.gmp` files are binary files and will only show random characters. That is normal. The safest approach is to ask the sender what software was used to create the file. If it came from a mapping or survey context, ask whether it should be opened in Global Mapper and whether they can export it to PDF, KML, SHP, DXF, GeoTIFF, or another format depending on what you need.In short, a GMP file is most commonly a Global Mapper Package File, especially when related to maps, land surveys, GPS, engineering, terrain, or property boundaries. It is a packaged GIS file that can contain actual map layers and geographic data. The safest way to open it is with Global Mapper, but if the file came from a game, Garmin GPS device, email marketing software, or another specialized program, it may belong to that software instead.