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

constantly change in time. It is therefore necessary to specify which epoch ITRF
coordinates refer to and to account for tectonic motion when changing epochs.The
countries defining their own datum connect it with ITRF to comply with the above
recommendations of IAG.
Establishment of Indian Geodetic Datum 2007 (IGD-2008) Strategy
The ideal solution for the present scenario may be establishment of the datum
based on dense network of Permanently Operating GPS Stations. This provides the
users an easy and quick access to the control. Developed countries like USA and
Canada have thousands of such stations in the form of CORS and CACS
respectively. However, for a developing country like India, it is not practicable to
establish thousands of permanent GPS stations with facilities to transmit the
differential corrections. It requires huge amount of money to establish and maintain
such system. The best option of India is to have a balanced approach using available
Permanent GPS stations along with dense network of campaign mode stations.
Observation Techniques
In India, the only space-based technique available at present is Global
Positioning System. So, the establishment of IGD2008 will be based on the GPS
technique. In future, if VLBI stations are set up in India, they will be used as the
highest accuracy points along with the GPS stations to connect the Indian datum
with ITRF as other developed countries have also done.
Data Sources
Realization of a geodetic datum requires the setting up of an accurate national
network of control points. It should include all the continuously operating GPS
stations and the campaign mode ground control points. India has the data sources in
the form of permanent GPS stations, GPS stations at tidal observatories and
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