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@UML(identifier="CD_Ellipsoid", specification=ISO_19111) public interface Ellipsoid
Geometric figure that can be used to describe the approximate shape of the earth. In mathematical terms, it is a surface formed by the rotation of an ellipse about its minor axis. An ellipsoid requires two defining parameters:
There is not just one ellipsoid. An ellipsoid is a matter of choice, and therefore many choices are possible. The size and shape of an ellipsoid was traditionally chosen such that the surface of the geoid is matched as closely as possible locally, e.g. in a country. A number of global best-fit ellipsoids are now available. An association of an ellipsoid with the earth is made through the definition of the size and shape of the ellipsoid and the position and orientation of this ellipsoid with respect to the earth. Collectively this choice is captured by the concept of "geodetic datum". A change of size, shape, position or orientation of an ellipsoid will result in a change of geographic coordinates of a point and be described as a different geodetic datum. Conversely geographic coordinates are unambiguous only when associated with a geodetic datum.
Field Summary |
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Fields inherited from interface IdentifiedObject |
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ALIAS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY |
Method Summary | |
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Unit |
getAxisUnit()
Returns the linear unit of the semi-major and semi-minor axis values. |
double |
getInverseFlattening()
Returns the value of the inverse of the flattening constant. |
double |
getSemiMajorAxis()
Length of the semi-major axis of the ellipsoid. |
double |
getSemiMinorAxis()
Length of the semi-minor axis of the ellipsoid. |
boolean |
isIvfDefinitive()
Indicates if the inverse flattening is definitive for this ellipsoid. |
boolean |
isSphere()
true if the ellipsoid is degenerate and is actually a sphere. |
Methods inherited from interface IdentifiedObject |
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getAlias, getIdentifiers, getName, getRemarks, toWKT |
Method Detail |
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@UML(identifier="getAxisUnit", specification=OGC_01009) Unit getAxisUnit()
@UML(identifier="semiMajorAxis", obligation=MANDATORY, specification=ISO_19111) double getSemiMajorAxis()
@UML(identifier="secondDefiningParameter.semiMinorAxis", obligation=CONDITIONAL, specification=ISO_19111) double getSemiMinorAxis()
@UML(identifier="secondDefiningParameter.inverseFlattening", obligation=CONDITIONAL, specification=ISO_19111) double getInverseFlattening()
isSphere()
returns true
),
the Double.POSITIVE_INFINITY
value is used.
@UML(identifier="CS_Ellipsoid.isIvfDefinitive", obligation=CONDITIONAL, specification=OGC_01009) boolean isIvfDefinitive()
true
if the inverse flattening is
definitive, or false
if the polar radius
is definitive.@UML(identifier="secondDefiningParameter.isSphere", obligation=CONDITIONAL, specification=ISO_19111) boolean isSphere()
true
if the ellipsoid is degenerate and is actually a sphere. The sphere is
completely defined by the semi-major axis, which is the
radius of the sphere.
true
if the ellipsoid is degenerate and is actually a sphere.
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