Use a text editor to edit the MyCoordSysDefs.fme file in your Reproject folder. This folder is located where FME was installed on your system. It is always good practice to create a backup copy of this file before you make any changes.
The projection and units of your source data are not predefined within FME, so, to define them, you must edit the mapping file to add the following lines:
Coordinate System Definition Lines | Additional Information |
---|---|
COORDINATE_SYSTEM_DEF <coordsysname> \ |
|
PROJ <projType> \ |
Table of projection types |
UNIT <unitName> \ |
Table of predefined units |
(DT_NAME <datumName> | EL_NAME <ellipName>) \ |
Table of predefined datums and predefined ellipsoids. Note that each coordinate system definition must specify either a datum or ellipsoid. |
[<parameter> <value>]+ \ |
|
[DESC_NM <descriptive_name>] \ |
|
[GROUP <group_name>] \ |
|
[QUAD <quadrant>] \ |
Quadrant definition |
[SOURCE <source>] \ |
|
[ZERO_X <zero_x>] \ |
|
[ZERO_Y <zero_y>] \ |
|
For example, this mapping file fragment defines a NAD83 based UTM Zone 12 coordinate system.
COORDINATE_SYSTEM_DEF UTM12N83 \ |
PROJ TM \ |
UNIT METER \ |
DT_NAME NAD83 \ |
PARM1 -111.0 \ |
GROUP "Custom Group" \ |
SCL_RED 0.9996 \ |
ORG_LAT 0.0 \ |
X_OFF 500000.0 \ |
Y_OFF 0.0 \ |
ZERO_X 0.001 \ |
ZERO_Y 0.001 |
Edit, save, and close the MyCoordSysDefs.fme file.
The custom coordinate system will appear in the columns of the Coordinate System Gallery. These columns are, in order, Name, Description, Group, Datum, Ellipsoid, Projection, and Units.
When
you update to a newer version of FME, the MyCoordSysDefs.fme
file is not overwritten. However, it is always good practice to back up any
custom files.
The parameters above are described in Coordinate System Parameters.
If you are working with custom mapping files and you set coordinate system definitions, you must remove the definitions after they are defined in the MyCoordSysDefs.fme file – the same coordinate system cannot be defined in both places.
See Also