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<DIV>Cleo,</DIV>
<DIV> </DIV>
<DIV>That’s right. You’re looking primarily at a 70cm difference in
height, but it varies a few centimeters as a function of latitude. Jose’s
instructions should nail it exactly, but I’m not a proj4 expert, so I leave you
in the hands of others more knowledgeable.</DIV>
<DIV> </DIV>
<DIV>Noel</DIV>
<DIV> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">Noel Zinn,
Principal, Hydrometronics LLC<BR>+1-832-539-1472 (office), +1-281-221-0051
(cell)<BR>noel.zinn@hydrometronics.com (email)<BR>http://www.hydrometronics.com
(website)<BR></DIV>
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style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV style="FONT: 10pt tahoma">
<DIV> </DIV>
<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A title=cleo21drakos@gmail.com
href="mailto:cleo21drakos@gmail.com">Cleo Drakos</A> </DIV>
<DIV><B>Sent:</B> Tuesday, August 19, 2014 6:29 PM</DIV>
<DIV><B>To:</B> <A title=proj@lists.maptools.org
href="mailto:proj@lists.maptools.org">PROJ.4 and general Projections
Discussions</A> </DIV>
<DIV><B>Subject:</B> Re: [Proj] Can I convert the ellipsoids using
Proj?</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV dir=ltr>Dear Noel
<DIV> </DIV>
<DIV>Thanks for your explanation. So it means that <FONT
face="arial, sans-serif">both ellipsoids have the same geocentric coordinates,
and I can use Jose's instruction.</FONT></DIV>
<DIV><FONT face="arial, sans-serif">I have four columns (lats, lons, elevation,
and geoid) in an ASCII file. I need to convert all these four parameters into
WGS84 system.</FONT></DIV>
<DIV><FONT face="arial, sans-serif">How can I apply Jose's instruction? I mean
how can I call c</FONT><SPAN
style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">s2cs for different
parameters? I did not know how to input these four parameters.</SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif"><BR></SPAN></DIV>
<DIV><SPAN style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">Sorry for this
type of question, I hope you do not mind.</SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif"><BR></SPAN></DIV>
<DIV class=gmail_extra>
<DIV> </DIV>
<DIV>
<DIV dir=ltr>cleo</DIV></DIV><BR><BR>
<DIV class=gmail_quote>On Tue, Aug 19, 2014 at 8:44 PM, Noel Zinn (cc) <SPAN
dir=ltr><<A href="mailto:ndzinn@comcast.net"
target=_blank>ndzinn@comcast.net</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV dir=ltr>
<DIV dir=ltr>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">
<DIV>Cleo,</DIV>
<DIV> </DIV>
<DIV>FAQ #7 under Altimetry products in the link you provide seems to answer
the question you ask. The FTP link in that paragraph leads you to
a program <A href="http://top2wgs.pro" target=_blank>top2wgs.pro</A> that
solves your problem. The program assumes dX = dY = dZ = 0. I’ve
made the same assumption myself with <FONT face="Times New Roman"><FONT
face=Calibri>TOPEX/Poseidon in a different context. Then follow Jose’s
cs2cs instructions.</FONT></FONT></DIV>
<DIV> </DIV>
<DIV>Thanks for the link.</DIV>
<DIV>
<DIV> </DIV>
<DIV>Noel</DIV>
<DIV> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">Noel
Zinn, Principal, Hydrometronics LLC<BR><A href="tel:%2B1-832-539-1472"
target=_blank value="+18325391472">+1-832-539-1472</A> (office), <A
href="tel:%2B1-281-221-0051" target=_blank
value="+12812210051">+1-281-221-0051</A> (cell)<BR><A
href="mailto:noel.zinn@hydrometronics.com"
target=_blank>noel.zinn@hydrometronics.com</A> (email)<BR><A
href="http://www.hydrometronics.com"
target=_blank>http://www.hydrometronics.com</A> (website)<BR></DIV></DIV>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV style="FONT: 10pt tahoma">
<DIV> </DIV>
<DIV style="BACKGROUND: #f5f5f5">
<DIV><B>From:</B> <A title=cleo21drakos@gmail.com
href="mailto:cleo21drakos@gmail.com" target=_blank>Cleo Drakos</A> </DIV>
<DIV><B>Sent:</B> Tuesday, August 19, 2014 3:39 AM</DIV>
<DIV><B>To:</B> <A title=proj@lists.maptools.org
href="mailto:proj@lists.maptools.org" target=_blank>PROJ.4 and general
Projections Discussions</A> </DIV>
<DIV><B>Subject:</B> Re: [Proj] Can I convert the ellipsoids using
Proj?</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV>
<DIV class=h5>
<DIV dir=ltr>Dear Jose<BR><BR>Thanks for your answer. Can you help me how can
I make certain that both ellepsoids have the same geocentric
coordinates.<BR>Only the information I am having is below under the section of
How does the GLAS ellipsoid compare with WGS 84?<BR><BR>
<DIV><A href="http://nsidc.org/data/icesat/faq.html#3_all"
target=_blank>http://nsidc.org/data/icesat/faq.html#3_all</A>
<DIV>
<DIV> </DIV>
<DIV class=gmail_extra>
<DIV> </DIV>
<DIV>
<DIV dir=ltr>cleo</DIV></DIV><BR><BR>
<DIV class=gmail_quote>On Tue, Aug 19, 2014 at 6:03 AM, Jose Gonçalves <SPAN
dir=ltr><<A href="mailto:jagoncal@gmail.com"
target=_blank>jagoncal@gmail.com</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV dir=ltr>
<DIV>Cleo<BR><BR>If cartesian geocentric coordinates are the same and you
just want to express them in a different ellipsoid you can do:<BR><BR>cs2cs
-f %.9f +a=6378136.30 +rf=298.257 +proj=latlong +towgs84=0,0,0 +to
+a=6378137 +rf=298.25722356 +proj=latlong +towgs84=0,0,0<BR><BR></DIV>
<DIV>If there are shift and rotation you can express them in the
+towgs84.<BR></DIV>
<DIV><BR>Regards<BR><BR></DIV>
<DIV>José <BR></DIV>
<DIV> </DIV></DIV>
<DIV class=gmail_extra><BR><BR>
<DIV class=gmail_quote>2014-08-18 15:13 GMT+01:00 Cleo Drakos <SPAN
dir=ltr><<A href="mailto:cleo21drakos@gmail.com"
target=_blank>cleo21drakos@gmail.com</A>></SPAN>:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV>
<DIV>
<DIV dir=ltr>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">Dear
guys,</DIV>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif"> </DIV>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">I have the
data (latitudes, longitudes, and elevations) given in ICESat/GLAS
ellipsoid. This equatorial radius and reciprocal flattening (1/f) on
this ellipsoid are 6378136.30 m and is 298.257 respectively.</DIV>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif"> </DIV>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">Now, I want to
convert my data into WGS84 ellepsoid with equatorial radius and reciprocal
flattening (1/f) of 6378137.000000 and 298.25722356 respectively.</DIV>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif"> </DIV>
<DIV style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">Can I convert
the ellipsoids using Proj?</DIV>
<DIV
style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif"> </DIV><SPAN
style="FONT-SIZE: 13px; FONT-FAMILY: arial,sans-serif">I hope some of you
can help me.</SPAN><SPAN><FONT color=#888888><BR>
<DIV class=gmail_extra>
<DIV> </DIV>
<DIV>
<DIV dir=ltr>cleo</DIV></DIV></DIV></FONT></SPAN></DIV>
<DIV> </DIV></DIV></DIV>
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