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<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Hello!<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>I’ve been asked if we support the "INDIAN
(Indian 1956)" geodetic datum, and I can’t <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>find it in the EPSG database. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>The site [1] lists an "Indian" datum using
the "Everest (<st1:country-region w:st="on"><st1:place w:st="on">India</st1:place></st1:country-region>
1956)" ellipsoid, with area of use:<o:p></o:p></span></font></p>
<p class=MsoNormal><st1:country-region w:st="on"><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'>India</span></font></st1:country-region><font
size=2 face=Arial><span lang=EN-US style='font-size:10.0pt;font-family:Arial'>
and <st1:place w:st="on"><st1:country-region w:st="on">Nepal</st1:country-region></st1:place>,
and geocentric translations dX=295 m, dY=736 m, dZ=257 m to WGS84.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>The article [2] tests this datum shift in <st1:country-region
w:st="on"><st1:place w:st="on">India</st1:place></st1:country-region>, and
gives the impression that this is an<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>important datum in <st1:country-region w:st="on"><st1:place
w:st="on">India</st1:place></st1:country-region>. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>The ellipsoid size and shape is the same as EPSG's
"Everest 1830 (1962 Definition)" ellipsoid.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>But in the EPSG database, this ellipsoid is used only
in EPSG's "Kalianpur 1962" datum, area <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>of use: "<st1:country-region w:st="on"><st1:place
w:st="on">Pakistan</st1:place></st1:country-region> - onshore". Could the
"Indian 1956" datum nevertheless be the same as<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>"Kalianpur 1962"? If not, is it the same as
some other EPSG datum?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>I noticed that the geocentric translations I cited
are the same as in EPSG tfm 1156,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>"Kalianpur 1975 to WGS 84 (1)". So maybe “INDIAN
(Indian 1956)” is the same as<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>EPSG’s “Kalianpur 1975”. But
the ellipsoid that EPSG gives for Kalianpur 1975 is <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>“Everest 1830 (1975 Definition)”, whose
equatorial radius is 2.092 meters shorter.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>The Remarks for tfm 1156 seems like an unofficial
deprecation:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'> “Care!
DMA ellipsoid is inconsistent with EPSG ellipsoid - transformation parameter<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'> values
may not be appropriate. Also source CRS may not apply to <st1:place w:st="on"><st1:country-region
w:st="on">Nepal</st1:country-region></st1:place>.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'> Derived
at 7 stations.”<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Anyway, I've heard that much geodetic information is
classified by <st1:place w:st="on"><st1:country-region w:st="on">India</st1:country-region></st1:place>,
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>but I am grateful for any hints.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Best regards, <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Mikael Rittri<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Carmenta<o:p></o:p></span></font></p>
<p class=MsoNormal><st1:place w:st="on"><st1:country-region w:st="on"><font
size=2 face=Arial><span lang=EN-US style='font-size:10.0pt;font-family:Arial'>Sweden</span></font></st1:country-region></st1:place><font
size=2 face=Arial><span lang=EN-US style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>http://www.carmenta.com<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>Links:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'>[1]
http://surveying.wb.psu.edu/sur351/DatumTrans/datum_transformations.htm<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>[2] http://www.gisdevelopment.net/technology/ip/ma03037pf.htm<o:p></o:p></span></font></p>
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