GEOO.APP

NTF to GML

Convert NTF to GML 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 NTF to GML format

Data Security

All processing is done locally in your browser

Standard Format

Output standard GML format

ntf to gml

Convert ntf to gml 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

About

NTF

UK NTF (National Transfer Format) is a geographic data exchange format defined by the UK Ordnance Survey, primarily used for distributing official UK topographic data. NTF is a complex binary format supporting multiple feature types and topological relationships. It is widely used in UK government and mapping departments.

GML

GML (Geography Markup Language) is an XML-based geospatial data encoding standard defined by the Open Geospatial Consortium (OGC). GML provides rich geospatial data modeling capabilities, supporting complex geometry types, topology, coordinate reference systems, and spatiotemporal data. GML is widely used in European and government sectors, often for national spatial data infrastructures (SDI).

Conversion trade-offs

NTF: limitations to know

  • UK-specific format with low international compatibility
  • Complex binary format, difficult to parse

GML: what you gain

  • Rigorous standard suitable for government and enterprise data exchange
  • Powerful data modeling for complex geographic concepts

Why convert NTF to GML?

Converting NTF to GML is one of the most common workflows in GIS. NTF data usually comes from desktop GIS software, government open-data portals, or data exchange with partners, while GML is what modern tools, web maps, and platforms expect. This converter bridges the two: it reads your NTF files, keeps geometry and attributes intact, and writes clean GML 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 NTF to GML converter free?

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

Are coordinate systems preserved when converting NTF to GML?

By default the output keeps the source coordinate system. If your NTF 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 NTF files at once and each one produces its own GML output.

GML at a glance

Key Features

  • OGC international standard with rigorous specification
  • Supports complex geometries, topology, and spatiotemporal data
  • Extensible Application Schema for domain-specific customization

Common Use Cases

  • Data exchange for national spatial data infrastructures (SDI)
  • Geographic data publishing by government and mapping agencies

How to Use

  1. 1

    Upload your NTF 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 GML file. Each input produces its own output, ready to use in your GIS, web map, or archive.