One common type of SDG file is a Strater Project File created by Golden Software Strater. Strater is a specialized program used in geology, drilling, mining, geotechnical engineering, environmental studies, groundwater studies, soil testing, and construction site investigation. In this context, an SDG file works as a project file rather than a finished document. It may store borehole views, well log layouts, depth-based data tables, lithology information, geological layer descriptions, graphs, legends, symbols, formatting settings, page layouts, and print or export settings. For example, a geotechnical team may record soil layers at different depths, such as topsoil, clay, sand, and limestone, then use Strater to turn that information into a visual borehole log. The `.sdg` file saves the editable project setup so the report can be reopened, modified, printed, or exported later.
An SDG file may also be connected to StarOffice, OpenOffice, or LibreOffice Gallery files. In this case, the file is usually not a normal document or standalone image. Instead, it is part of the office suite’s Gallery system, which stores and organizes reusable visual resources such as clipart, icons, background images, decorative graphics, bullets, and other media items. Gallery themes may include several related files, such as `.sdg`, `.sdv`, and `.thm`, which work together to help the program display and manage gallery items. Because of this, a LibreOffice or OpenOffice SDG file is usually handled by the office application itself and is not meant to be opened directly like a Word document, spreadsheet, or standard image file.
There are also other less common software-specific SDG formats. Some smaller, older, or specialized programs may use the `.sdg` extension for their own project data, drawing information, database records, export files, configuration files, thumbnails, backups, or internal resources. This happens because file extensions are not always exclusive. Different software developers can use the same extension for different purposes. As a result, two files may both end in `.sdg` but contain completely different data. One may be a Strater project, another may be a LibreOffice gallery support file, and another may belong to a lesser-known application.
To open an SDG file, the best first step is to identify the program that created it. If the file came from a geology, drilling, borehole, well log, mining, environmental, or geotechnical project, it may need to be opened with Golden Software Strater. If the file was found inside a LibreOffice, OpenOffice, StarOffice, Gallery, Themes, Presets, Share, or User Config folder, it may be a gallery support file that is managed inside the office suite rather than opened directly. If the file source is unknown, users should check the folder location, file properties, file size, modified date, sender, and any nearby companion files such as `.sdv`, `.thm`, `.csv`, `.dat`, `.xml`, or `.ini`.
It is also important not to rename an SDG file just to force it open. Changing a filename from `file.sdg` to `file.pdf`, `file.jpg`, or `file.docx` does not convert the file into that format. It only changes the label, while the actual internal data remains the same. This can make the file even harder to identify or open correctly. If conversion is needed, it usually has to be done through the original software. For example, a Strater SDG project may need to be opened in Strater first, then exported to a more common format such as PDF, image, or report file.
If an SDG file came from an unknown email sender, a download, an old USB drive, or a backup with no clear source, it should be handled carefully. The `.sdg` extension itself is not automatically dangerous, but unfamiliar files can be misidentified, corrupted, unnecessary, or unsafe. Users should scan unknown SDG files with security software before opening them and avoid downloading random "SDG opener" programs from untrusted websites. The safest approach is to confirm the file’s origin, identify the software that created it, and open it only with a trusted application that supports that specific type of SDG file.