Coordinate Systems

Select Tools > FME Options and click the Coordinate Systems icon.

Working with the CS-MAP Library

How to determine which grid shift files are installed

A number of grid shift files are included when you install FME. For details, see Included Grid Shift Files.

Implicit NAD27 to NAD83 Transformation

Specify which grid shift file to use for performing implicit NAD27 to NAD83 transformations, NAD27 <-> NAD83 (Canada Only) or NAD27 <-> NAD83 (USA Only). If not specified, FME prompts for a selection at workspace runtime.

Maintain Grid Transformations

This option allows you to maintain and edit grid files. To manage grid files, select a file and click Edit. The dialog that appears lists one or more grid shift files:

  • Add button: Opens a file browser so you can select a new file and add it to the list.
  • Remove button: Removes a selected file.

Note: We recommend that you make sure that the grid files you need are in the list, and that you remove any files that you do not need.

  • Fallback: Select the datum to use if the selected grid file does not cover the area of your input data. Fallback datums are listed in individual .gdc files, which you can open with any text editor.
  • Move Up and Move Down buttons: Note that these buttons will rearrange the list, but they do not determine the order of precedence of the grid files.

Click OK to apply changes, and Cancel to discard changes.

WARNING: If you add a file, you are not copying the file – you are only pointing to the file’s location. Thus, if you delete a file from its original location, the entry you create here will point to a nonexistent file. Safe Software recommends that you copy each grid file to FME’s Reproject\GridData subfolder before adding any files to your configuration.

To add a grid shift file to FME

Follow these steps to install a grid file so that FME will recognize the file:

  1. Copy the new file to FME's Reproject\GridData subfolder.
  2. Select Tools > FME Options and click the Coordinate Systems icon.
  3. Select the applicable datum shift and click the Edit button.
  4. A dialog displays the files already recognized by FME for the applicable datum shift. To include new files, click the Add button, browse to the applicable folder and find the file in Reproject\GridData subfolder.
  5. Select the file and click OK.

More Information

For additional information on grid shift files, see the Coordinate Systems section of this help file, or view these specific topics:

How FME Handles Grid Files

Included Grid Shift Files

Working with the PROJ Library

  • Online Grids Enabled: When performing PROJ library reprojections with applicable transformers, such as PROJReprojector and PROJAttributeReprojector, many of the necessary grid shift files are already included with FME. When checked, this setting allows online access to a PROJ grid files library for other necessary grid files. The online library is accessed only if FME cannot locate the applicable file on the local system.
  • Maximum Cache Size: The maximum disk cache size, in megabytes, to allocate on the local system when accessing PROJ grid files. To minimize latency, adjust the cache size according to your system's specifications and requirements. A negative value (default) means the cache size is unlimited. A value of 0 means no caching is performed.
  • CDN Endpoint: The Content Delivery Network (CDN) endpoint for accessing PROJ grid files.