Named SRFs in SEDRIS

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Named SRFs in SEDRIS
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SRF Hierarchy
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Coordinate System Hierarchy
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ERM Characteristics

• Shape spherical, ellipsoidal, geoidal
• Size radius, semi-major axis
• Center Location usually relative to WGS 84
• Orientation usually same as WGS 84
• Rotational Axis Plane poles equator
• Prime Meridian e.g., Greenwich
• Domain of Validity

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ORM/ERM Hierarchy
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EGM96 Geoid
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ERM Transformations
LTP,GCS,GEI,etc.
LTP,GCS,GEI,etc.
WGS 84 Ellipsoid
Source ERM
Target ERM
Geocentric
Geocentric
Geocentric
Shift
Shift
Geodetic
Geodetic
Geodetic
Molodensky WGS72 to WGS84
Molodensky WGS84 to WGS72
Projection- Based SRFs
Projection- Based SRFs
Note Molodenskys method cannot be used near the
poles