Dec 2005 | Comments Off on Geodetic infrastructure in India
table1

The Great Trigonometrical Survey of India was completed in 19th century under leadership of the great surveyors- Lambton and Sir George Everest. It is inconsistent and inadequate. Accuracy of the network is only of the 1st order or less. First order was defined as better than only 1 in 50,000 only. Reference surface and Datum- The Everest Spheroid was given by Sir George Everest in 1830. Center of Everest Spheroid is about a km away from the center of gravity of the Earth; hence it is non-geocentric. Thus it is inaccurate and unsuitable under present circumstances. Leveling network of India has inconsistencies. Gravity observations were not carried out and not taken in to consideration. It was not appropriately adjusted. Indian Absolute Gravity Datum does not exist. Absolute gravimeters have not yet been used to define Gravity Datum in India. Topographical maps are on Polyconic projection. Assumptions and approximations accepted make it a non-projection. The earth is assumed to be fiat and there are no distortions of any kind. The projection has created problems in digitization, compilation and integration of maps. Design of the Grid adopted in India is not satisfactory. Distortion at central parallel is 1 in 824, which is quite high. There is archaic Restriction policy, which is not transparent and hinders research and development India has to make a choice between chaos and development. These problems have been discussed in detail in this paper. How India should go about to establish new geodetic infrastructure for systematic development and research, has been described in this paper.

Dec 2005 | Comments Off on Measuring geopotential difference between two points
graph1

Conventionally, the potential difference between two points P and Q located on the Earth’s surface are determined by gravimetry and levelling (Heiskanen and Moritz 1967), the drawback of which is that it is almost impossible to connect these two points in the case that they are located on two continents, because it is well known that the potential surface of the mean sea level (MSL) is not an equipotential surface. In another aspect, if given the gravity data on the Earth’s surface, one might determine the potential difference between two points by using the Stokes method or Molodensky method (ibid). In this case the potential field is determined and consequently the potential difference between two arbitrary points could be determined.

Dec 2005 | Comments Off on ACRS: The journey continues…

 

26th ACRS 2005, 7-11, November, 2005 Hanoi, Vietnam

 
 

The 26th Asian Conference on Remote Sensing (ACRS) and 2nd …

Dec 2005 | Comments Off on “A web-based transport system is well developed in Hong Kong”
chen

says Prof. YQ Chen, Department of Land Surveying and …

Dec 2005 | Comments Off on Volume I, Issue 7, December 2005
May issue

Measuring geopotential difference between two points W B SHEN
Geodetic infrastructure in India N K AGRAWAL
Geodetic Misunderstanding MUNEENDRA KUMAR
Multiple reference station GPS networks for airborne navigation AHMED EL- MOWAFY
Developing a platform to facilitate sharing spatial data ABBAS RAJABIFARD, ANDREW BINNS AND IAN WILLIAMSON
NSDI in India: Reality behind a dream
Photogrammetric mapping MRIDUL KUMAR

Dec 2005 | Comments Off on My Coordinates

 
 
 

NSDI in India: A dream being pursued
 
National Spatial Data Infrastructure (NSDI) …

Dec 2005 | Comments Off on Signal propagation through the ionosphere
17

The Indian ionosphere is characterized by large horizontal gradients, intense irregularities, large dayto- day variations and equatorial anomaly conditions, there is clear necessity to thoroughly understand the ionospheric time delay effects on the GPS signals. The ionospheric delay error is a function of Total electron content (TEC) which is one of the dominant errors.

Dec 2005 | Comments Off on Geodetic commentary
p

The Mix up of “X, Y, Z” Coordinates Between Photogrammetry and Geodesy
In Spatial considerations –
In geodesy, the “ZXY” coordinate system is “right-handed”, where the right thumb points towards the Z-axis, index finger towards the intersection of the Reference Meridian and Equatorial planes, and middle ?nger or the positive Y-axes, which is …

Dec 2005 | Comments Off on MARK YOUR CALENDAR

December 2005

 

Gulf First Urban Planning and Development Conference 12-14 …

Dec 2005 | Comments Off on NEWSBRIEFS – GPS

India to Use Russian GLONASS Navigation System
Russia and India are planning to cooperate in the sphere of satellite navigation, Indian Defense Minister Pranab Mukherjee announced at a Moscow recently. He said this was a momentous decision for India, but that the specifics of cooperation in the area had yet to be discussed. Russia’s satellite navigation system, called GLONASS, is operated for the government by the its Space Forces. An improved GLONASS-K satellite, with a reduced weight and an increased operational lifetime of 10-12 years, is due to enter service in 2008. Following a joint venture deal with the Indian government, which will launch two GLONASS-M satellites on its PSLV rockets, it is proposed to have the system fully operational again by 2008 with 18 satellites and by 2010 with all 24 satellites.