GML → CAL · Windows

Convert GML to CAL

GML to CAL offline, so survey, cadastral and client data never goes through an upload form. No file size limit and no per-file quota.

Tired of converting GML files one at a time? reaConverter processes entire folders to CAL automatically. Handles large batches reliably without crashes or timeouts. Survey and cadastral data stays on your machine, with no upload at any point.

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GML to CAL
Online
.gml.CAL
4.8

Converting files since 2001

Runs offline — nothing uploaded

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How to Convert Multiple .gml Layers to .cal?

1. Download and Install reaConverter

First, grab reaConverter from the download button below. Installation is fast, and the software runs offline — no account or signup needed.

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Install reaConverter

2. Load your GML files

Add GML files to reaConverter. One file or a thousand, the process is the same. Everything runs locally on your machine.

You can drag-and-drop files, browse to a folder, or add entire directory trees including subfolders.

Load your GML files into reaConverter

3. Select CAL as output format

Set CAL as output format and select where to save your converted files. Customize quality settings if needed.

Select CAL as output format

4. Start GML to CAL conversion

Click the Convert button to start. reaConverter will process all your files with the settings you selected.

Start Conversion

When finished, your new .cal files will be waiting in the destination folder.

Step by step

How It Works

reaConverter offers the fastest, simplest solution for converting your GML files into CAL without GIS software - all files processed on your PC for maximum privacy and speed.

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Technical note

How GML and CAL differ in practice

A GML file holds geometry and an attribute table, and nothing at all about appearance. Colours, line weights, fills and labels are properties of the GIS project rather than of the file, which is why the same GML looks different in every program that opens it. The CAL render therefore falls back on defaults and will not match the styled map you see in QGIS or ArcGIS. Expect a clean drawing of the geometry rather than a finished cartographic product. GML coordinates are positions on the earth, tied to a stated reference system, and each feature carries its own row of attributes. CAL is a picture: the coordinates become pixel positions and the attribute table is dropped entirely. That is fine for illustration and no use as data, so keep the GML original if anything downstream needs to query or reproject the features.

Map Data Workflow

Turn GIS data into something anyone can open

Not everyone who needs to see GML data has GIS software. reaConverter renders it to CAL for a report, an email or a slide, and handles a whole folder in one run.

  • Render every file in a folder to CAL with the same size and settings
  • Set DPI and output dimensions before the run, not afterwards
  • Pick up new data automatically with Watch Folders, or script the job from the command line

Everything runs on your PC, which matters for cadastral, utility and client data that should not pass through an upload form.

GIS data conversion

User reviews

What people say after the first batch

Average User Rating:4.8
Last updated on September 28, 2026
An excellent program! I use it regularly in my work - it supports nearly every file format imaginable. The interface is intuitive and runs flawlessly every time.
Roger Cook
Roger Cook
Happy User
For agencies handling confidential data, reaConverter eliminates cloud-upload risks while delivering unmatched conversion reliability. Our team uses it both in-office and remotely with identical results.
Jamal Bailey
Jamal Bailey
Satisfied Customer
Our volunteer team uses reaConverter to prepare images for fundraising campaigns. The learning curve was minimal, and the results are professional-grade. The customer support team even helped us customize a workflow — fantastic service!
Jason P. Bailey
Jason P. Bailey
Non-Profit Coordinator
An efficient all-in-one solution for image conversion and light editing, designed for maximum user-friendliness.
Elena Anderson
Elena Anderson
Happy User
Enable shell integration for lightning-fast file conversions directly from Windows Explorer.
R. Lewis
R. Lewis
Happy User
After 200+ conversions on my budget laptop (i3-1115G4/4GB RAM/Win11), reaConverter outperforms heavyweight tools. Zero crashes, low CPU usage during batch processing, and no internet dependency - exactly what professionals need.
Walter Morgan
Walter Morgan
Satisfied Customer

FAQ

GML to CAL Conversion

What are GML files?

GML (Geography Markup Language) is an XML-based language for describing geographic features, developed by the Open Geospatial Consortium (OGC) and adopted as the international standard ISO 19136. A GML file is readable text in which every object on a map, such as a building, a road, a lake, or a boundary, is written down together with its shape and its attributes, for example a name, a type, or a population. The language is a toolbox rather than a fixed list of objects: communities and organizations define their own application schemas on top of it, which is how national mapping data, cadastral records, and the data of 3D city models are exchanged. GML is also the standard way for web map services to return features.

What are CAL files?

A CAL image file represents a monochrome bitmap image that uses the CALS raster image standard for storing graphics data. This standard was created in the 1980s by the US Department of Defence as a compressed interchangeable image format. CAL and CALS are extensions used for similar purposes.

Can reaConverter convert GML to CAL?

Yes! reaConverter instantly converts .gml to .cal with perfect quality preservation. With its batch processing feature, you can convert multiple files at once in just a few clicks. You can even convert GML files directly from Windows Explorer using the right-click menu — fast and convenient.

What is reaConverter used for?

reaConverter is a Windows converter for 800+ formats, GIS data among them. For GML to CAL it replaces the usual detour through QGIS, ArcGIS or ogr2ogr: add the files, pick the output format, and the whole batch converts offline. Surveyors, planners and engineering teams use it to pass data between GIS, CAD and everyday document formats.

Why choose offline conversion with reaConverter?

reaConverter is a software program that is used for offline files conversion. Your proprietary documents never leave your computer – essential for architects, engineers, healthcare and government contractors handling classified projects. Meets GDPR, HIPAA, CCPA, and corporate security policies by ensuring files never cross borders or third-party systems.

Can I convert GML to CAL online?

If you only need to convert a few GML files to CAL format, feel free to try our free online free online GML to CAL converter — perfect for small batches with no installation needed!

How can I turn GML files into CAL on my computer?

The best way to change GMLs to CALs on your PC is to install 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 GML to CAL.

How can I automate GML to CAL files conversion?

reaConverter supports all the most useful automation features such as right-click сonversion and Watch Folders for the most efficient automated files conversion in any software of this type.

Is there a way to convert GML files to CAL using the command prompt?

reaConverter provides full access to all its features via Windows command line, including a high-performance command-line gml to cal converter for batch processing.

What else can I do with reaConverter?

Convert RAW formatsConvert microscopy filesPicture resizerConvert GIS filesConvert CAD formats

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