10.6.1 Cartographic Projection Transform Parameters
The valid parameters for the mandatory cartographic projection transforms are listed below. These include parameters for the semi-major and semi-minor axis of their ellipsoid in meters.
These ellipsoid parameters can be skipped when the projection WKT is being embedded inside a Projected Coordinate System see Well-Known Text format details, since the PCS ellipsoid will
override the projection transform ellipsoid.
10.6.1.1 Transverse_Mercator Projection
Parameter Description of units
semi_major Meters semi_minor
Meters latitude_of_origin
Degrees central_meridian Degrees
scale_factor No units
false_easting Meters false_northing Meters
10.6.1.2 Lambert_Conformal_Conic_1SP
Parameter Description of units
semi_major Meters semi_minor
Meters latitude_of_origin
Degrees central_meridian Degrees
scale_factor No units
false_easting Meters false_northing Meters
10.6.1.3 Lambert_Conformal_Conic_2SP
Parameter Description of units
semi_major Meters semi_minor
Meters latitude_of_origin
Degrees central_meridian Degrees
standard_parallel1 Degrees standard_parallel2 Degrees
false_easting Meters false_northing Meters
Page 35 of 117 OGC Document Number 01-009
11 Referencing objects by ID versus Value
External authorities may be used to manage definitions of objects used in this Interface Specification. The definitions of these objects are referenced using code strings. The codes and
authority names can be embedded in WKT strings or XML, using an AUTHORITY clause. If there is an AUTHORITY clause, and the reader recognizes the authority name, then the reader
is entitled to use the authority’s definition, and ignore all the other values at that level in the definition. How the reader consults the authority is outside the scope of this Interface
Specification. To improve interoperability, writers of WKT and XML must always include a copy of all the values,
as well as any AUTHORITY clause. Readers will use the values as opposed to the authority code in the following cases:
1 There is no AUTHORITY clause 2 The reader does not recognize the authority
3 The reader fails to create an object using the authority code The last case where the reader recognizes the authority name, but fails to create an object using
the code can happen if the reader is using a different version of the authority from the writer. In order to avoid misinterpretations, the following guidelines for authorities are recommended:
a The authority name or namespace must be registered by OGC b The authority must not reuse old code strings for “different” entities.
11.1 Registered WKT Authorities
Kategori