High Resolution 1:10,000 scale Mapping Strategy of Multi ... - NDMA

APPENDIX VIII
GROUND CONTROL POINTS IN PROCUREMENT OF
1:10,000 SATELLITE IMAGES
PHOTOGRAMMETRIC GROUND CONTROL
DATUM
By definition, the horizontal datum is a rectangular plane coordinate system. All
horizontal control shall begin and terminate on monuments that are in the National
Geodetic Reference Database System (NGRDS)
The vertical datum is normal to gravity. All vertical control shall begin and terminate
on existing benchmarks that are in the National Geodetic Reference Database
System (NGRDS).
International Terrestrial Reference Frame (ITRF) is a realization of International
Terrestrial Reference System (ITRS), which is a definition of geocentric system
adopted and maintained by International Earth Rotation and Reference Systems
Service (IERS). IERS was established in 1987 on the basis of the resolutions by
IUGG and IAG. The origin of the system is the centre of mass of the Earth. The unit
of length is meter. The orientation of the axes was established as consistent with that
of IERS’s predecessor, Bureau International de l’Heure, BIH, in 1984. The Z-axis is
the line from the Earth’s centre of mass through the Conventional International Origin
(CIO). Between 1900 and 1905, the mean position of the Earth’s rotational pole was
designated as the Conventional Terrestrial Pole (CTP). The X-axis is the line from
the centre through the intersection of the zero meridian with the equator. The Y-axis
is the line from the centre to equator and perpendicular to X axis to make a right
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