PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
March 2014
211
— without communications and full of jungles, wild animals,
robbers and disease. The average length of a side of the tri-
angulation was about 31 miles, the maximum being about
62 miles. One cannot imagine how such long-distance obser-
vations were planned, laid down on the ground, line of sight
cleared of all trees and sometimes even houses, and how big
rivers and swamps were crossed. Everest, devoted to his work,
did all this despite his partial paralysis and bad health. Based
on his conceptualization, the gridiron network today covers
the entire country and forms a solid foundation for accurate
surveys and mapping for defense, development and efficient
administration. It was with the help of this gridiron network
that the highest peak of the world was observed and discov-
ered in 1852 and its height declared as 29,002 ft. -
i.e.
about
8840 meters. After fresh observations and computations, the
Survey of India declared its height in 1954 as 8848 meters.
In 1975, the Chinese put a metallic beacon on Everest and
observed it from 9 stations. They also carried out sufficient
astronomical and gravimetrical measurements, the coefficient
of refraction was reliably determined and the final result of
the determination was declared as 8848.13 ± 0.35 meters. Sir
Thomas Holdick concluded in the Standard of January 24,
1905 that ‘It was officers of the Survey of India who placed
his name just near the stars, than that of any other lover of
eternal glory of the mountains and let it stay in witness to the
faithful work not of one man but scores of men.’ Everest was
the first from amongst the eight Surveyors General of India to
be knighted” (
Survey of India Through the Ages, by Lt. Gener-
al S. M. Chadha, delivered at the Royal Geographical Society
on 8 November 1990, on the eve of Sir George Everest Bicente-
nary celebration by the Surveyor General of India
).
Slightly more than one-third the size of the U.S., India is
bordered by Bangladesh (4,053 km) (
PE&RS
, March 2008),
Bhutan (605 km), Burma (1,463 km) (
PE&RS
, Septem-
ber 2013), China (3,380 km) (
PE&RS
, May 2000), Nepal
(1,690 km) (
PE&RS
, June 20138), and Pakistan (2,912 km)
(
PE&RS
, July 2009). The lowest point is the Indian Ocean (0
m), and the highest point is Kānchenjunga (8,598 m)
(World
Factbook, 2014)
.
“The bulk of the geodetic triangulation in India was carried
out with large theodolites between 1802 and 1882. Its simul-
taneous adjustment involved a decade’s labor. In the 20
th
cen-
tury, very little was done in the way of geodetic triangulation
– only a few outlying series in Baluchistan and Burma having
been observed. The presence of Military Survey Companies
in the different theaters during WWII and in the period im-
mediately following it enabled important gaps between the
triangulation of India and its neighboring countries like Iraq,
Iran, Siam and Malaya to be filled. A continuous chain of tri-
angulation now exists from Syria to Malaya”
(Geodetic Work
in India – War and Post-War, B.L.Gulatee, Empire Survey
Review, No. 77, Vol. X, 1950)
.
The origin of the Indian Adjustment of 1916 is at sta-
tion Kalianpur (Strong Base) where: Φ
o
= 24° 07' 11.26" N,
Λ
o
= 77º 39' 17.57" East of Greenwich, α
o
= 190º 27' 05.10"
from Kalianpur to Surantal, and the ellipsoid of reference
is the Everest 1830
(India)
where:
a
= 6,377,301.243 m,
1
/
f
= 300.8017
(UK Military Survey, 1982)
. The adjustment
depended on baselines evenly distributed throughout India.
The use of LaPlace stations had not yet been adopted by the
Survey of India; consequently errors in azimuth and position
were introduced. These errors are particularly evident in the
triangulation series of southern India. The 1880 adjustment
has however, remained the basis of all Indian triangulation
and mapping. Therefore there is no such thing as an “Indian
Datum;” it is only an adjustment!
(JMN, 21 June 1997)
In 1924 the “Minute Mesh” was introduced. This is a refer-
ence system consisting of meridians and parallels at one min-
ute intervals: descriptive references are given by a convenient
system of lettering, and all survey computations are done in
spherical terms in the usual way”
(Geodetic Report, Survey of
India, CPT. G. Bomford, R.E., 1930)
. “As the result of a deci-
sion arrived at the artillery survey conference held at Akora
on 12
th
January 1926, two forms and a set of tables were pre-
pared for the conversion of the spherical co-ordinates to rect-
angular, and
vice versa
, on Lambert’s conical orthomorphic
projection. This projection is also known as Lambert’s second
projection with two standard parallels”
(Geodetic Report, Sur-
vey of India, CPT. G. Bomford, R.E., 1928)
.
Seven separate India Zones were created in 1926 by the
Survey of India, all seven having the same scale factor at
origin (m
o
) = 823/824 = 0.998786408, the same False Easting
= 3,000,000 Indian Yards, and the same False Northing =
1,000,000 Indian Yards. The following parameters differ: Zone
I has φ
o
= 32º 30' N & λ
o
= 68º E; Zone IIA has φ
o
= 26º N &
λ
o
= 74º E; Zone IIB has φ
o
= 26º N & λ
o
= 90º E; Zone IIIA has
φ
o
= 19º N & λ
o
= 80º E, Zone IIIB has φ
o
= 19º N & λ
o
= 100º
E, Zone IVA has φ
o
= 12º N & λ
o
= 80º E, and Zone IVB has
φ
o
= 12 N & λ
o
= 104º E. As a hint for the readers that need the
actual two standard parallels for each of the above India Zones
expressed with the British Method of defining Lambert pa-
rameters; for India Zone I, the equivalent standard parallels
are 35º 18' 50.3486" N and 29º 39' 18.7703" N. The requisite
equations to solve for the other India Zones are in Chapter 3 of
the Manual of Photogrammetry, editions 5 and 6.
Because there is no unified datum in existence for the
sub-continent of India, there is a significant difference in
transformation parameters from Indian 1916 to WGS84 from
region to region. The Survey of India is slowly releasing geo-
detic and cartographic data to the general public after main-
taining a significant degree of secrecy for centuries. Curious-
ly, the India Lambert Zones are for restricted military use,
and civilian applications in GIS for India seem to prefer the
U.S. military’s Universal Transverse Mercator Grid System.
The contents of this column reflect the views of the author, who is
responsible for the facts and accuracy of the data presented herein.
The contents do not necessarily reflect the official views or policies of
the American Society for Photogrammetry and Remote Sensing and/
or the Louisiana State University Center for GeoInformatics (C
4
G).
