GMapTool: The Complete Guide for Geospatial File Management

GMapTool: The Complete Guide for Geospatial File Management

What GMapTool is

GMapTool is a desktop utility for managing Garmin-format map files (primarily .img/.gmap). Its main functions are merging and splitting Garmin map files, installing mapsets for MapSource/BaseCamp/HomePort, and editing map properties (IDs, names, priority, transparency, creation date, label case, and TYP replacements). It provides both GUI and command-line (gmt.exe) modes for scripting.

Key features

• Merge multiple .img maps into a single mapset.
• Split .img files into mapsets, individual maps, or subfiles.
• Install/uninstall mapsets for Windows, macOS, and (community) Linux setups.
• Edit map metadata: map/mapset IDs, names, creation dates, priority, transparency.
• Modify map content: change label case, remove national characters, replace TYP files.
• Create preview maps via external compilers (cGPSMapper or MapTk).
• Command-line support for batch processing and automation.

Typical workflows

1. Merge maps:
   • Add source .img files in Files tab → Join tab: set output path and mapset name → “Join all”.
2. Split maps:
   • Open .img → select Split options (by map, subfile or tile) → run split to extract components.
3. Install for MapSource/BaseCamp:
   • Use provided install batch (Windows) or copy .gmap directory to Garmin maps folder; for macOS use Garmin MapManager instructions.
4. Edit map properties:
   • Use Properties dialog to change IDs, priority, transparency or replace TYP files; save changes to output .img or mapset.
5. Automate:
   • Use gmt.exe in scripts to run joins, splits, or property edits without GUI.

Requirements and setup

• Windows recommended for full GUI; macOS and Linux versions exist (installation steps differ).
• For preview map creation, install an external compiler: cGPSMapper (free/paid) or MapTk, then set its path in Options.
• Download and documentation: official site https://www.gmaptool.eu (includes manuals, basic/advanced task pages, installation instructions, and changelog).

Tips and caveats

• Back up original .img files before modifying IDs or overwriting files.
• When installing on modern Windows, use the provided install_MAP.bat which creates symbolic links (avoids copying).
• Replacing TYP files changes map appearance—test visually in MapSource/BaseCamp first.
• Command-line gmt.exe is useful for batch map processing in pipelines.

Sources: GMapTool official documentation and task pages (https://www.gmaptool.eu).