Introduction
Starting in FME 2025.2, the Coordinate System parameter is no longer displayed as a top-level field in the user interface.
Instead, FME automatically inserts the coordinate system parameter into the format’s parameter configuration dialog if specific metadata conditions are met.
For more information on the user interface changes, see Coordinate System Parameter Location Change.
This automatic addition behaviour is temporary. It will be removed in FME 2026.1. To ensure your plugin continues to support coordinate system configuration, you’ll need to update your metafiles accordingly.
Automatic Insertion Conditions (FME 2025.2)
FME will automatically insert the Coordinate System parameter if your format’s metadata meets both of the following conditions based on formats.db:
- The FORMAT TYPE is not equal to non-spatial
- COORD SYS AWARE field is set to Yes
This allows spatial formats to temporarily surface the parameter without requiring metafile updates.
This behavior will no longer apply in FME 2026.1.
Migration Instructions
To maintain coordinate system support beyond FME 2026.1 update your metafiles as follows:
If your plugin supports reading, locate the SOURCE_SETTINGS keyword in the metafile (.fmf), and before the END_SOURCE_SETTINGS keyword, add the following lines:
DEFAULT_VALUE COORDINATE_SYSTEM
GUI OPTIONAL COORDSYS COORDINATE_SYSTEM Coordinate System:
If your plugin supports writing, locate the `DESTINATION_SETTINGS` keyword in the metafile (.fmf) and before the `END_DESTINATION_SETTINGS` keyword, add the following lines:
DEFAULT_VALUE COORDINATE_SYSTEM
GUI OPTIONAL COORDSYS COORDINATE_SYSTEM Coordinate System:
This pair of lines defines a coordinate system parameter named COORDINATE_SYSTEM, marks it as optional, and provides the label that will appear in the UI. No additional code changes are required. In FME 2025.2 and before, the UI automatically added this parameter to the reader and writer settings. As of FME 2026.1, it will no longer be added automatically and must be present in the format metafile in order to define the coordinate system that will be set on features read, or the coordinate system in which features will be written.
Compatibility Notes
Once this change is applied, your updated plugin will be compatible with:
- FME 2025.2 and newer, where the parameter will appear correctly in the Parameters dialog
Note: With FME 2025.1 and older, the parameter will appear duplicated within the format parameters and the top-level field.
Tip for testing: In FME 2025.1, if you see a duplicated Coordinate System field (one at the top level, one in the Parameters dialog), this confirms that your migration was successful. You can test user behavior and confirm proper mapping.
Important: In older versions, if the user selects different coordinate system values in each of the duplicated fields, results may be unpredictable. Encourage consistent usage and document expected behavior if supporting earlier FME versions.
If you have any questions or concerns, please contact Safe Software Support.