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