Defining New Ellipsoids

Certain sites may require an ellipsoid that is not predefined in the FME. In such a case, a custom ellipsoid may be created. Ellipsoid definitions may occur in an FME mapping file, as well as in the LocalCoordSysDefs.fme.

The syntax of an ellipsoid definition is:

ELLIPSOID_DEF <ellipsoidName> \
   DESC_NM <descriptive name> \
   SOURCE <source> \
   E_RAD <equator radius> \
   P_RAD <polar radius>

Example Ellipsoid Definition

This mapping file fragment defines a sample ellipsoid:

ELLIPSOID_DEF myEllipse \
   DESC_NM “Safe Sample Ellipse” \
   SOURCE “Safe Software Inc.” \
   E_RAD 6377340.128 \
   P_RAD 63356034.448

Ellipsoid Definition Parameters

Name	Range	Description	Optional
<ellipsoidName>	any string	The name of the ellipsoid being de­fined.	No
<descriptive name>	any string	A descriptive name for the ellipsoid.	Yes
<source>	any string	The individual or agency providing the ellipsoid parameters.	Yes
<equator radius>	floating point value	The radius of the ellipsoid in meters at the equator.	No
<polar radius>	floating point value	The radius of the ellipsoid in meters in the polar direction.	No