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JSON-FG to GML

JSON-FG to GML Converter Online | GeoDataViewer

Quick answer: Convert JSON-FG to GML online for free. Open your JSON-FG data, inspect the map preview, and download GML output locally in your browser — no upload required. JSON-FG is an OGC geospatial JSON format that builds on familiar JSON patterns while supporting richer geospatial semantics than classic GeoJSON alone.

Before converting JSON-FG to GML

Prepare the input

Choose a complete JSON-FG dataset (.jsonfg, .json). Keep required sidecar files together and check the source coordinate reference system.

Know what you download

GML output is downloaded as a file, or ZIP when the driver generates sidecars. Compare the result against the source before sharing.

Limits and troubleshooting
  • Converting JSON-FG to GML can change field types, metadata and presentation. A successful download does not prove every source element survived.
  • Browser memory varies by device. There is no guaranteed unlimited file size; split large datasets or use a desktop GIS when memory or WASM initialization fails.

If something goes wrong

  • Empty or partial preview: confirm the source contains supported vector geometry and compare the source layers with the preview.
  • Wrong continent or distorted geometry: inspect the source CRS, axis order and a known location. Valid syntax alone does not guarantee valid placement.
  • Conversion cannot start: reload while online so processing libraries and WebAssembly can load, then retry a smaller known-good sample. File contents are still processed locally.
  • Incomplete export: compare source/output counts, geometry families and key fields. Inspect warnings and keep the original file.
Source Format Guide

What is JSON-FG?

JSON-FG is an OGC geospatial JSON format that builds on familiar JSON patterns while supporting richer geospatial semantics than classic GeoJSON alone.

JSON-FG was created to make JSON-based geospatial exchange more expressive for modern data needs, including cases where classic GeoJSON assumptions become restrictive.

It is appealing to teams that want JSON ergonomics but also need clearer feature typing, more explicit geospatial semantics, and a path beyond older web-only conventions.

Common Workflows

Common use cases

  • Experimental or standards-driven API payloads.
  • Data pipelines that want JSON readability but more formal semantics.
  • Converting modern OGC-aligned datasets into web-friendly JSON form before distribution.
Ecosystem

Where you will encounter it

  • OGC-aligned experiments and modern API design.
  • JSON-centric geospatial exchange workflows.
  • Toolchains that need more semantics than classic GeoJSON.
Strengths

Why teams choose JSON-FG

  • Keeps the practical benefits of JSON while extending geospatial expressiveness.
  • Better fit for workflows that outgrow classic GeoJSON assumptions.
  • Strong option for systems that want modern standards alignment in JSON form.
Limitations

Where JSON-FG gets awkward

  • Ecosystem support is still narrower than GeoJSON because not every tool reads JSON-FG yet.
  • Teams may still need a fallback conversion for older clients.
  • Some users are less familiar with it, which can slow adoption outside standards-aware environments.
Conversion steps

How to convert JSON-FG to GML online

  1. 1. Add your JSON-FG file

    Drop the source data into the converter above. Keep any required sidecar files together when your dataset uses them.

  2. 2. Check the map preview

    Inspect the geometry and attributes before exporting so you can spot missing layers or coordinate-system issues.

  3. 3. Download GML

    Run the conversion and save the generated GML output directly from your browser. Your source file stays on your device.

File Structure

Common file extensions and sidecar files

.jsonfg
Common extension used to signal that the JSON document follows JSON-FG conventions.
.json
Generic JSON extension sometimes used in practice, though it is less explicit than .jsonfg.
Conversion Rationale

Why convert JSON-FG to GML?

Teams commonly convert JSON-FG into GML when they need an XML-based standards workflow that fits formal data exchange requirements.

  • Teams convert JSON-FG when downstream systems only understand older formats such as GeoJSON, shapefile, or KML.
  • They also convert into JSON-FG when they want a JSON representation with richer semantics than a plain GeoJSON export.
  • GML is commonly used where schema-driven exchange and standards compliance matter more than file size.
  • It is a frequent target in enterprise, government, and specification-heavy environments.
FAQ

Frequently asked questions about JSON-FG to GML

What do I need before converting JSON-FG to GML?

Choose a complete JSON-FG dataset (.jsonfg, .json). Keep required sidecar files together and check the source coordinate reference system.

What exactly is in the GML download?

GML output is downloaded as a file, or ZIP when the driver generates sidecars. Compare the result against the source before sharing.

How large a JSON-FG file can I convert?

The practical limit depends on browser memory, geometry complexity and the conversion driver. Start with a small sample. There is no guaranteed unlimited size and no cloud fallback or payment tier for large files.

Are my JSON-FG files sent to a server?

File parsing and conversion run on your device. The page, WebAssembly and map basemaps can make network requests; choosing a file does not upload its contents. Load the required libraries before attempting offline work.

Related Converters

More JSON-FG conversion paths

JSON-FG to GeoJSON
Open, preview, and convert JSON-FG data locally in your browser.
JSON-FG to GeoPackage
Open, preview, and convert JSON-FG data locally in your browser.
JSON-FG to ESRI Shapefile
Open, preview, and convert JSON-FG data locally in your browser.

Format workflow cluster

More JSON-FG and GML workflows

Use the related viewer, tools, guides, and conversion paths to continue the same GIS task without losing the source format context.