FME defines a large number of units (for example, meters, US feet, degrees, radians, etc.). If your coordinate system is measured in a unit that FME does not already know about, you can define the new unit.
Unit definitions may occur in an FME mapping file, as well as in the file:
LocalCoordSysDefs.fme
The syntax of a unit definition is:
UNIT_DEF <unit name>
\
UNIT_TYPE <unit type> \
UNIT_ABBREVIATION <unit abbreviation> \
UNIT_FACTOR <unit size>
|
Name |
Range |
Description |
Optional |
|---|---|---|---|
|
<unit name> |
any string |
The name of the unit being defined. |
No |
|
<unit type> |
ANGLE | LENGTH |
Specifies whether the unit measures angles or lengths. |
No |
|
<unit abbreviation> |
any string |
This abbreviation represents the unit and may be used in coordinate system definitions instead of the <unitname>. |
No |
|
<unit size> |
Floating-point number |
The size of a unit in metres if it measures length. If the unit measures angle, then this is the size in degrees. |
No |
Example Unit Definition
In this example, we define the unit “GRIDUNIT” (abbreviated as “GRD”) where the unit length is 0.999738 meters.
UNIT_DEF GRIDUNIT \
UNIT_TYPE LENGTH \
UNIT_ABBREVIATION GRD \
UNIT_FACTOR 0.999738