Regardless of all said after Ken's initial question, the Lat-Longs between
coordinate systems should be the same, and yes I have seen this variation in
Ermapper before, but can't remember why.
Regards,
Vic Mitchell
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]
Sent: Wednesday, August 22, 2001 3:04 AM
Subject: ERMAPPER-L Daily Digest
----------------------------------------------------------------------
From: "Ken Hickey" <[EMAIL PROTECTED]>
Subject: reprojection precision
Date: Wed, 21 Nov 2001 11:50:03 -0800
Reply-To: [EMAIL PROTECTED]
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G'day all
I just reprojected a batch of GeoTiffs (USGS DOQQs) from Nad83 to Nad27 =
using the Batch reprojection wizard from ERM. I have noticed that the =
same point on the photo now longer has the same Lat and Long in the 2 =
projections (the UTM coordinates for the same points are different, but =
that is mean't to be the case I believe - ?). I used a bilinear =
resampling method for the reprojection, but the same thing happened if I =
used the nearest neighbour method.
The point in Nad83 has UTM coordinates (zone11) 561392.93E / =
4544597.60N; 41:3:7.94N / 116:16:10.06W
The same point in Nad27 is 561314.00E / 4544799.00N; 41:3:7.62N / =
116:16:13.37W
Is this sort of variation in Lat and Long normal?
Thanks in advance
Cheers
Ken Hickey
------------------------------------------------------------------
Dr Kenneth Hickey
Mineral Deposit Research Unit (MDRU)
Department of Earth and Ocean Sciences
University of British Columbia
6339 Stores Rd, Vancouver, BC V6T 1Z4, Canada
phone +1-604-822-3765; Fax +1-604-822-6088
email: [EMAIL PROTECTED]
=20
.
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<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 5.50.4616.200" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>G'day all</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT size=3D2><FONT face=3DArial>I just reprojected a batch of =
GeoTiffs (USGS=20
DOQQs) from Nad83 to Nad27 using the Batch reprojection wizard from =
ERM. I=20
have noticed that the same point on the photo now longer has the same =
Lat and=20
Long in the 2 projections (the UTM coordinates for the same points are=20
different, but that is mean't to be the case I believe - ?). I used =
a=20
bilinear resampling method for the reprojection, but the same thing =
happened if=20
I used the nearest neighbour method.</FONT></FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The point in Nad83 has UTM coordinates=20
(zone11) 561392.93E / 4544597.60N; 41:3:7.94N / =
116:16:10.06W</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The same point in Nad27 is 561314.00E / =
4544799.00N; 41:3:7.62N / 116:16:13.37W</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Is this sort of variation in Lat and =
Long=20
normal?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Thanks in advance</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Cheers</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Ken Hickey</FONT></DIV>
<DIV><FONT face=3DArial=20
size=3D2><BR>------------------------------------------------------------=
------<BR>Dr=20
Kenneth Hickey<BR>Mineral Deposit Research Unit (MDRU)<BR>Department of =
Earth=20
and Ocean Sciences<BR>University of British Columbia<BR>6339 Stores Rd,=20
Vancouver, BC V6T 1Z4, Canada<BR>phone +1-604-822-3765; Fax=20
+1-604-822-6088<BR>email: <A=20
href=3D"mailto:[EMAIL PROTECTED]";>[EMAIL PROTECTED]</A><BR> <BR>.<=
BR></FONT></DIV></BODY></HTML>
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Date: Tue, 21 Aug 2001 17:01:03 -0400
From: Jean-Yves Lauture <[EMAIL PROTECTED]>
Subject: Re: reprojection precision
Reply-To: [EMAIL PROTECTED]
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Content-Type: text/plain; charset="us-ascii"; format=flowed
Hello Ken,
Of course your coordinate will be different from one datum to another (only
Nad83 and WGS 84 are basically the same). Datum is a spheroid to represent
best the earth for the region in which you are. If the spheroid parameters
change, the "earth also changes".
Read page 440 of the 6.0 User Guide (chap 28). you can also read Chap 27.
Regards,
Jean-Yves
At 11:50 2001-11-21 -0800, you wrote:
>G'day all
>
>I just reprojected a batch of GeoTiffs (USGS DOQQs) from Nad83 to Nad27
>using the Batch reprojection wizard from ERM. I have noticed that the same
>point on the photo now longer has the same Lat and Long in the 2
>projections (the UTM coordinates for the same points are different, but
>that is mean't to be the case I believe - ?). I used a bilinear resampling
>method for the reprojection, but the same thing happened if I used the
>nearest neighbour method.
>
>The point in Nad83 has UTM coordinates (zone11) 561392.93E / 4544597.60N;
>41:3:7.94N / 116:16:10.06W
>The same point in Nad27 is 561314.00E / 4544799.00N; 41:3:7.62N /
>116:16:13.37W
>
>Is this sort of variation in Lat and Long normal?
>
>Thanks in advance
>
>Cheers
>Ken Hickey
>
>------------------------------------------------------------------
>Dr Kenneth Hickey
>Mineral Deposit Research Unit (MDRU)
>Department of Earth and Ocean Sciences
>University of British Columbia
>6339 Stores Rd, Vancouver, BC V6T 1Z4, Canada
>phone +1-604-822-3765; Fax +1-604-822-6088
>email: <mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED]
>
>.
Jean-Yves Lauture
Geomatics Representative
****************************************************************************
***
Geneq inc.
8047, Jarry East - Montreal, Quebec (CANADA) - H1J 1H6
Tel: 1-800-463-4363
Tel: (514) 354-2511 - Fax: (514) 354-6948
e-mail: [EMAIL PROTECTED]
http://www.geneq.com
****************************************************************************
***
--=====================_29830794==_.ALT
Content-Type: text/html; charset="us-ascii"
<html>
Hello Ken,<br>
<br>
Of course your coordinate will be different from one datum to another
(only Nad83 and WGS 84 are basically the same). Datum is a spheroid to
represent best the earth for the region in which you are. If the spheroid
parameters change, the "earth also changes".<br>
<br>
Read page 440 of the 6.0 User Guide (chap 28). you can also read Chap
27.<br>
<br>
Regards,<br>
<br>
Jean-Yves<br>
<br>
<br>
At 11:50 2001-11-21 -0800, you wrote:<br>
<blockquote type=cite class=cite cite><font face="arial" size=2>G'day
all</font><br>
<br>
<font face="arial" size=2>I just reprojected a batch of GeoTiffs (USGS
DOQQs) from Nad83 to Nad27 using the Batch reprojection wizard from ERM.
I have noticed that the same point on the photo now longer has the same
Lat and Long in the 2 projections (the UTM coordinates for the same
points are different, but that is mean't to be the case I believe - ?). I
used a bilinear resampling method for the reprojection, but the same
thing happened if I used the nearest neighbour method.</font><br>
<br>
<font face="arial" size=2>The point in Nad83 has UTM coordinates (zone11)
561392.93E / 4544597.60N; 41:3:7.94N / 116:16:10.06W</font><br>
<font face="arial" size=2>The same point in Nad27 is 561314.00E /
4544799.00N; 41:3:7.62N / 116:16:13.37W</font><br>
<br>
<font face="arial" size=2>Is this sort of variation in Lat and Long
normal?</font><br>
<br>
<font face="arial" size=2>Thanks in advance</font><br>
<br>
<font face="arial" size=2>Cheers</font><br>
<font face="arial" size=2>Ken Hickey</font><br>
<font face="arial" size=2><br>
------------------------------------------------------------------<br>
Dr Kenneth Hickey<br>
Mineral Deposit Research Unit (MDRU)<br>
Department of Earth and Ocean Sciences<br>
University of British Columbia<br>
6339 Stores Rd, Vancouver, BC V6T 1Z4, Canada<br>
phone +1-604-822-3765; Fax +1-604-822-6088<br>
email: <a href="mailto:[EMAIL PROTECTED]";>[EMAIL PROTECTED]</a><br>
<br>
.</font></blockquote>
<x-sigsep><p></x-sigsep>
<b><i><br>
Jean-Yves Lauture<br>
</b>Geomatics Representative<br>
<br>
</i>************************************************************************
*******<br>
<b>Geneq inc.<br>
</b><i>8047, Jarry East - Montreal, Quebec (CANADA) - H1J 1H6<br>
Tel: 1-800-463-4363<br>
Tel: (514) 354-2511 - Fax: (514) 354-6948<br>
e-mail: [EMAIL PROTECTED]<br>
</i><a href="http://www.geneq.com/";
eudora="autourl">http://www.geneq.com</a><br>
****************************************************************************
***<br>
</html>
--=====================_29830794==_.ALT--
----------------------------------------------------------------------
From: "Leo Romeyn" <[EMAIL PROTECTED]>
Subject: Re: reprojection precision
Date: Tue, 21 Aug 2001 18:23:42 -0500
Reply-To: [EMAIL PROTECTED]
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Jean-Yves:
You have to be careful!
A Datum is NOT a Spheroid! A Spheroid will be associated with a Datum, =
e.g.: NAD-83 is a Geocentric Datum (Earth Centered Earth Fixed-ECEF), =
were the Geodetic Reference System of 1980 (GRS-80) Spheroid is used. =
With the "Old" NAD-27 Datum, the Clarke 1866 Spheroid was used and the =
Datum origin, were the Astronomical derived Coordinates of Station =
Meades Ranch are the Origin Coordinates of the NAD-27 Datum, with a =
Clarke 1866 Spheroidal Height of 0.0 m.
Best regards,
Leo J. Romeyn
Geodetic Positioning Service Inc.
Satellite Imaging Corporation
11802 Marrs Drive
Houston, TX 77065-1202
Tel: 713.932.6375
Fax: 281.890.7051
E-mail: [EMAIL PROTECTED]=20
----- Original Message -----=20
From: Jean-Yves Lauture=20
To: [EMAIL PROTECTED]=20
Sent: Tuesday, August 21, 2001 04:01 PM
Subject: Re: reprojection precision
Hello Ken,
Of course your coordinate will be different from one datum to another =
(only Nad83 and WGS 84 are basically the same). Datum is a spheroid to =
represent best the earth for the region in which you are. If the =
spheroid parameters change, the "earth also changes".
Read page 440 of the 6.0 User Guide (chap 28). you can also read Chap =
27.
Regards,
Jean-Yves
At 11:50 2001-11-21 -0800, you wrote:
G'day all
=20
I just reprojected a batch of GeoTiffs (USGS DOQQs) from Nad83 to =
Nad27 using the Batch reprojection wizard from ERM. I have noticed that =
the same point on the photo now longer has the same Lat and Long in the =
2 projections (the UTM coordinates for the same points are different, =
but that is mean't to be the case I believe - ?). I used a bilinear =
resampling method for the reprojection, but the same thing happened if I =
used the nearest neighbour method.
=20
The point in Nad83 has UTM coordinates (zone11) 561392.93E / =
4544597.60N; 41:3:7.94N / 116:16:10.06W
The same point in Nad27 is 561314.00E / 4544799.00N; 41:3:7.62N / =
116:16:13.37W
=20
Is this sort of variation in Lat and Long normal?
=20
Thanks in advance
=20
Cheers
Ken Hickey
------------------------------------------------------------------
Dr Kenneth Hickey
Mineral Deposit Research Unit (MDRU)
Department of Earth and Ocean Sciences
University of British Columbia
6339 Stores Rd, Vancouver, BC V6T 1Z4, Canada
phone +1-604-822-3765; Fax +1-604-822-6088
email: [EMAIL PROTECTED]
=20
.
Jean-Yves Lauture
Geomatics Representative
=
*************************************************************************=
******
Geneq inc.
8047, Jarry East - Montreal, Quebec (CANADA) - H1J 1H6
Tel: 1-800-463-4363
Tel: (514) 354-2511 - Fax: (514) 354-6948
e-mail: [EMAIL PROTECTED]
http://www.geneq.com
=
*************************************************************************=
******
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<HTML><HEAD>
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<BODY bgColor=3D#ffffff>
<DIV><FONT face=3D"Courier New">Jean-Yves:</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3D"Courier New">You have to be careful!</FONT></DIV>
<DIV><FONT face=3D"Courier New"></FONT> </DIV>
<DIV><FONT face=3D"Courier New">A Datum is NOT a Spheroid! A Spheroid =
will be=20
associated with a Datum, e.g.: NAD-83 is a Geocentric Datum (Earth =
Centered=20
Earth Fixed-ECEF), were the Geodetic Reference System of 1980 (GRS-80) =
Spheroid=20
is used. With the "Old" NAD-27 Datum, the Clarke 1866 Spheroid was used =
and the=20
Datum origin, were the Astronomical derived Coordinates of Station =
Meades=20
Ranch are the Origin Coordinates of the NAD-27 Datum, with a Clarke 1866 =
Spheroidal Height of 0.0 m.</FONT></DIV>
<DIV><FONT face=3D"Courier New"></FONT> </DIV>
<DIV><FONT face=3D"Courier New">Best regards,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3D"Courier New">Leo J. Romeyn</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3D"Courier New">Geodetic Positioning Service =
Inc.</FONT></DIV>
<DIV><FONT face=3D"Courier New">Satellite Imaging =
Corporation</FONT></DIV>
<DIV><FONT face=3D"Courier New">11802 Marrs Drive</FONT></DIV>
<DIV><FONT face=3D"Courier New">Houston, TX 77065-1202</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3D"Courier New">Tel: 713.932.6375</FONT></DIV>
<DIV><FONT face=3D"Courier New">Fax: 281.890.7051</FONT></DIV>
<DIV><FONT face=3D"Courier New">E-mail: <A=20
href=3D"mailto:[EMAIL PROTECTED]";>[EMAIL PROTECTED]</A></FONT> </DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:[EMAIL PROTECTED]"; =
[EMAIL PROTECTED]>Jean-Yves=20
Lauture</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:[EMAIL PROTECTED]"=20
[EMAIL PROTECTED]>[EMAIL PROTECTED]</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, August 21, 2001 =
04:01=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: reprojection =
precision</DIV>
<DIV><BR></DIV>Hello Ken,<BR><BR>Of course your coordinate will be =
different=20
from one datum to another (only Nad83 and WGS 84 are basically the =
same).=20
Datum is a spheroid to represent best the earth for the region in =
which you=20
are. If the spheroid parameters change, the "earth also =
changes".<BR><BR>Read=20
page 440 of the 6.0 User Guide (chap 28). you can also read Chap=20
27.<BR><BR>Regards,<BR><BR>Jean-Yves<BR><BR><BR>At 11:50 2001-11-21 =
-0800, you=20
wrote:<BR>
<BLOCKQUOTE class=3Dcite cite type=3D"cite"><FONT face=3Darial =
size=3D2>G'day=20
all</FONT><BR> <BR><FONT face=3Darial size=3D2>I just =
reprojected a batch=20
of GeoTiffs (USGS DOQQs) from Nad83 to Nad27 using the Batch =
reprojection=20
wizard from ERM. I have noticed that the same point on the photo now =
longer=20
has the same Lat and Long in the 2 projections (the UTM coordinates =
for the=20
same points are different, but that is mean't to be the case I =
believe - ?).=20
I used a bilinear resampling method for the reprojection, but the =
same thing=20
happened if I used the nearest neighbour =
method.</FONT><BR> <BR><FONT=20
face=3Darial size=3D2>The point in Nad83 has UTM coordinates =
(zone11) 561392.93E=20
/ 4544597.60N; 41:3:7.94N / 116:16:10.06W</FONT><BR><FONT =
face=3Darial=20
size=3D2>The same point in Nad27 is 561314.00E / 4544799.00N; =
41:3:7.62N /=20
116:16:13.37W</FONT><BR> <BR><FONT face=3Darial size=3D2>Is =
this sort of=20
variation in Lat and Long normal?</FONT><BR> <BR><FONT =
face=3Darial=20
size=3D2>Thanks in advance</FONT><BR> <BR><FONT face=3Darial=20
size=3D2>Cheers</FONT><BR><FONT face=3Darial size=3D2>Ken =
Hickey</FONT><BR><FONT=20
face=3Darial=20
=
size=3D2><BR>------------------------------------------------------------=
------<BR>Dr=20
Kenneth Hickey<BR>Mineral Deposit Research Unit (MDRU)<BR>Department =
of=20
Earth and Ocean Sciences<BR>University of British Columbia<BR>6339 =
Stores=20
Rd, Vancouver, BC V6T 1Z4, Canada<BR>phone +1-604-822-3765; =
Fax=20
+1-604-822-6088<BR>email: <A=20
=
href=3D"mailto:[EMAIL PROTECTED]";>[EMAIL PROTECTED]</A><BR> <BR>.<=
/FONT></BLOCKQUOTE><X-SIGSEP>
<P></X-SIGSEP><B><I><BR>Jean-Yves Lauture<BR></B>Geomatics=20
=
Representative<BR><BR></I>***********************************************=
********************************<BR><B>Geneq=20
inc.<BR></B><I>8047, Jarry East - Montreal, Quebec (CANADA) - H1J =
1H6<BR>Tel:=20
1-800-463-4363<BR>Tel: (514) 354-2511 - Fax: (514) 354-6948<BR>e-mail: =
[EMAIL PROTECTED]<BR></I><A href=3D"http://www.geneq.com/"=20
=
eudora=3D"autourl">http://www.geneq.com</A><BR>**************************=
*****************************************************<BR></P></BLOCKQUOTE=
></BODY></HTML>
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