GEOO.APP

GMT to GeoJSON

Convert GMT to GeoJSON online for free — right in your browser. No upload, no sign-up, batch conversion, coordinate systems and attributes preserved.

Features

Fast Conversion

Efficiently convert from GMT to GEOJSON format

Data Security

All processing is done locally in your browser

Standard Format

Output standard GEOJSON format

gmt to geojson

Convert gmt to geojson online for free — right in your browser. No upload, no sign-up, batch conversion, coordinate systems and attributes preserved.

Drag and drop files or folders, or click to upload

Related Tools

GEOJSON → GMTSHP → GEOJSONKML → GEOJSONGML → GEOJSONTOPOJSON → GEOJSONGEOPACKAGE → GEOJSONCSV → GEOJSONXLSX → GEOJSONGEOJSON → SHPGEOJSON → KML

About

GMT

GMT ASCII Vectors is a text-based vector data format used by Generic Mapping Tools (GMT) software. GMT is widely used in earth science research and academic paper map making. The GMT format records geographic features as text lines, each containing coordinates and optional attribute information.

GeoJSON

GeoJSON is a geospatial data interchange format based on JSON. It can represent Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection geometries. Defined by RFC 7946, GeoJSON has become one of the most popular data exchange formats in web GIS. GeoJSON files use WGS84 coordinates and support Feature objects with associated properties and FeatureCollections for organizing multiple features.

Conversion trade-offs

GMT: limitations to know

  • Only used in GMT software ecosystem, low universality
  • Does not support complex attributes and style information

GeoJSON: what you gain

  • Human-readable, easy to manually edit and debug
  • Supported by virtually all GIS software and mapping libraries
  • Naturally suited for web applications and API data transmission

Why convert GMT to GeoJSON?

Converting GMT to GeoJSON is one of the most common workflows in GIS. GMT data usually comes from desktop GIS software, government open-data portals, or data exchange with partners, while GeoJSON is what modern tools, web maps, and platforms expect. This converter bridges the two: it reads your GMT files, keeps geometry and attributes intact, and writes clean GeoJSON output — entirely in your browser, so your data never leaves your device.

Frequently asked questions

Are my files uploaded to a server?

No. The conversion runs entirely in your browser using WebAssembly — your files never leave your device.

Is the GMT to GeoJSON converter free?

Yes, completely free with no sign-up and no usage limits.

Are coordinate systems preserved when converting GMT to GeoJSON?

By default the output keeps the source coordinate system. If your GMT file uses a projected CRS (like UTM), you can search any EPSG coordinate system by keyword or code and reproject in one step. Note: output formats that require WGS84 by specification (KML, KMZ, GPX) always reproject to WGS84 automatically.

Can I convert multiple files at once?

Yes — drop several GMT files at once and each one produces its own GeoJSON output.

GeoJSON at a glance

Key Features

  • Based on standard JSON, natively supported by all programming languages
  • Supports multiple geometry types: Point, LineString, Polygon, MultiPolygon, etc.
  • Can carry attribute data and supports FeatureCollection for batch organizing features

Common Use Cases

  • Data exchange for web maps and online mapping services
  • Geospatial data storage and display in mobile applications
  • Sharing and transporting GIS data across platforms

How to Use

  1. 1

    Upload your GMT file — drag and drop it onto the page, or browse from your device. You can add several files at once for batch conversion.

  2. 2

    The conversion runs automatically in your browser. No upload, no server — your data stays on your device the entire time.

  3. 3

    Download the GeoJSON file. Each input produces its own output, ready to use in your GIS, web map, or archive.