[Proj] Is the "INDIAN (Indian 1956)" datum in the EPSG database?

Mikael Rittri Mikael.Rittri at carmenta.com
Thu Nov 29 05:24:02 EST 2012

I've been asked if we support the "INDIAN (Indian 1956)" geodetic datum, and I can't
find it in the EPSG database.

The site [1] lists an "Indian" datum using the "Everest (India 1956)" ellipsoid, with area of use:
India and Nepal, and geocentric translations dX=295 m, dY=736 m, dZ=257 m to WGS84.
The article [2] tests this datum shift in India, and gives the impression that this is an
important datum in India.

The ellipsoid size and shape is the same as EPSG's "Everest 1830 (1962 Definition)" ellipsoid.
But in the EPSG database, this ellipsoid is used only in EPSG's "Kalianpur 1962" datum, area
of use: "Pakistan - onshore". Could the "Indian 1956" datum nevertheless be the same as
"Kalianpur 1962"? If not, is it the same as some other EPSG datum?

I noticed that the geocentric translations I cited are the same as in EPSG tfm 1156,
"Kalianpur 1975 to WGS 84 (1)". So maybe "INDIAN (Indian 1956)" is the same as
EPSG's "Kalianpur 1975".  But the ellipsoid that EPSG gives for Kalianpur 1975 is
"Everest 1830 (1975 Definition)", whose equatorial radius is 2.092 meters shorter.
The Remarks for tfm 1156 seems like an unofficial deprecation:

        "Care! DMA ellipsoid is inconsistent with EPSG ellipsoid - transformation parameter
         values may not be appropriate. Also source CRS may not apply to Nepal.
         Derived at 7 stations."

Anyway, I've heard that much geodetic information is classified by India,
but I am grateful for any hints.

Best regards,

Mikael Rittri


[1] http://surveying.wb.psu.edu/sur351/DatumTrans/datum_transformations.htm

[2] http://www.gisdevelopment.net/technology/ip/ma03037pf.htm
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.maptools.org/pipermail/proj/attachments/20121129/6c9cb641/attachment.htm 

More information about the Proj mailing list