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GMT Converter
Survey, cadastral and client data should not go through an upload form. reaConverter converts GMT files offline, with no size limit.
How to Convert .gmt Files in Bulk
1. Install reaConverter
2. Select GMT Files
3. Start Conversion
Step by step
See It in Action
For quick and effortless GMT file handling on your PC, reaConverter offers powerful conversion tools with batch processing. Best of all, it works entirely offline — ensuring your sensitive data never leaves your computer.
GIS Toolkit
Do more with your GIS data
Need GMT data in someone else's software? reaConverter moves layers between GIS, CAD and document formats without QGIS or ArcGIS, and works through whole folders in one pass.
- Move layers between GIS formats such as Shapefile, GeoJSON, KML, KMZ and GPX
- Bring map data into CAD as DXF or DWG, and turn CAD drawings into Shapefiles
- Render maps to PDF, SVG, PNG or JPG for reports, slides and print
- Convert incoming survey and field data automatically with Watch Folders
- Script GIS conversions from the command line for pipelines and scheduled jobs
- Keep cadastral, utility and client data on your PC: nothing is uploaded
User reviews
From those who tried it
Average User Rating:Last updated on July 28, 2026
Questions & Answers
GMT files: Frequently Asked Questions
What are GMT files?
GMT (GMT ASCII Vectors) is a plain-text vector format in two flavors. An old, simple file holds only coordinates, one pair per line, and it is treated as a set of points, or as lines if a segment header starting with the character > appears before the first vertex. A new-style file follows the OGR/GMT convention and begins with a comment line that starts with # @VGMT1.0, which activates the extended parsing. The same line may declare the geometry type, for example @GPOINT, @GLINESTRING, or @GPOLYGON, the names of attribute fields after @N, separated by vertical bars, and their types after @T, such as string, double, or integer. Further comments give the region with @R and the coordinate system with @J, and the line # FEATURE_DATA ends the header. Each feature then has its own segment header, which may carry plot options and attribute values after @D, and a polygon uses @P for the outer ring and @H for holes. All features in one file must have the same geometry type, and each layer is written as a separate .gmt file. Unlike Shapefile, the shapes and the attributes live in a single file. The older versions of the Generic Mapping Tools also used the .gmt extension for a binary data file, so the content must be checked. Supported by the Generic Mapping Tools.
Can reaConverter open GMT files?
reaConverter fully supports the GMT file format – open, edit, and export GMT files to any other popular file format with ease.
Do I need QGIS or ArcGIS to convert GMT files?
No. reaConverter reads GMT files on its own, so the conversion needs no GIS installation and no licence. It handles whole folders at once, which suits survey archives, tile sets and data deliveries that have to reach people working in other software.
How do I change GMT to another format?
reaConverter is a user-friendly tool for converting GMT files. Once installed on your computer, it allows you to convert all your .gmt files at once with just a few clicks. You can even convert gmt images directly from Windows Explorer using the right-click menu — fast and convenient.
Why choose offline conversion with reaConverter?
Keep your sensitive data 100% private with offline processing that never exposes files to cloud risks. Our software meets strict compliance standards (GDPR, HIPAA, CCPA) while handling confidential documents for legal, healthcare and financial sectors.
Can I convert GMT online?
If you only want to convert a few GMT files, you are welcome to try our free online GMT converter.
How can I turn GMT files on my computer to another format?
The best way to convert GMT files on your PC is to get a quality piece of software, such as reaConverter. This software is extremely efficient in managing a wide range of batch files conversions, including conversion from GMT.
How can I automate GMT files conversion?
reaConverter supports all the essential automation features, such as right-click сonversion and Watch Folders, for the most efficient automated file conversion in any software of its kind.
Can I convert GMT files using scripts or the command-line interface?
reaConverter provides full access to all its features from the Windows command-line shell, including the command-line gmt converter.
What else can I do with reaConverter?
Convert vector filesChange image DPIChange format settingsCopy IPTC dataConvert Gerber files
What formats can I convert a GMT file to?
Discover More
Beyond GMT conversion
Convert .gmt files in batches of any size, with editing and processing applied along the way. The same tool also handles 800+ other formats, including CAD, medical imaging, and GIS.
