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<DIV><FONT size=2>Ed,</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I do mean grid convergence of the projection.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>It sort of is lat / long except it isn't. Everything is
projected to UTM, then localized to the center of the area and rotated by the
grid convergence. Possibly all that I need to do is rotate the image, which
again, I am not sure what would be the most efficient method.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Thanks for you patience.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Steve</FONT></DIV>
<DIV> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ed@topozone.com href="mailto:ed@topozone.com">Ed McNierney</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=gdal-dev@remotesensing.org
href="mailto:gdal-dev@remotesensing.org">gdal-dev@remotesensing.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, August 19, 2003 3:33
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [Gdal-dev] Warp /
rotation</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=467172021-19082003><FONT face=Arial color=#0000ff
size=2>Steve -</FONT></SPAN></DIV>
<DIV><SPAN class=467172021-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=467172021-19082003><FONT face=Arial color=#0000ff
size=2>Sorry, I don't mean to sound dense, but how do you define
"convergence"? Do you mean the grid convergence of the UTM
projection (for example) at that point?</FONT></SPAN></DIV>
<DIV><SPAN class=467172021-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=467172021-19082003><FONT face=Arial color=#0000ff size=2>It
sounds like you might be trying to select an area that is a rectangle in
latitude/longitude and then clipping that area out of the UTM source image and
reprojecting the results to a "geographic" (lat/long) projection. Is
that correct? If not, please set me straight -
thanks!</FONT></SPAN></DIV>
<DIV><SPAN class=467172021-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=467172021-19082003> <FONT face=Arial
color=#0000ff size=2>- Ed</FONT></SPAN></DIV>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> Geographic Wizard
[mailto:geowiz@shaw.ca]<BR><B>Sent:</B> Tuesday, August 19, 2003 5:00
PM<BR><B>To:</B> gdal-dev@remotesensing.org<BR><B>Subject:</B> Re:
[Gdal-dev] Warp / rotation<BR><BR></FONT></DIV>
<DIV><FONT size=2>It'a a dynamic rotation, the convergence of whatever
coordinate system you are woirking in, at the center of your area ot
interest.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Steve</FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ed@topozone.com href="mailto:ed@topozone.com">Ed McNierney</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=gdal-dev@remotesensing.org
href="mailto:gdal-dev@remotesensing.org">gdal-dev@remotesensing.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, August 19, 2003 2:47
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [Gdal-dev] Warp /
rotation</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=906544320-19082003><FONT face=Arial color=#0000ff
size=2>I think you missed the point - a rectangle rotated is no longer a
rectangle. It's a four-sided polygon, a quadrilateral, etc. - what's
important is that you are requesting an area that, expressed in the source
coordinate system, is not rectangular. If the Y coordinates of the
lower left and lower right corners are different, it's not a
rectangle.</FONT></SPAN></DIV>
<DIV><SPAN class=906544320-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=906544320-19082003><FONT face=Arial color=#0000ff
size=2>Can you provide a rigorous definition of your rotation?
"About 2 degrees CW" isn't precise enough. If you can describe it
mathematically, we can help you implement it!</FONT></SPAN></DIV>
<DIV><SPAN class=906544320-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=906544320-19082003> <FONT face=Arial
color=#0000ff size=2>- Ed</FONT></SPAN></DIV>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> Geographic Wizard
[mailto:geowiz@shaw.ca]<BR><B>Sent:</B> Tuesday, August 19, 2003 4:37
PM<BR><B>To:</B> gdal-dev@remotesensing.org<BR><B>Subject:</B> Re:
[Gdal-dev] Warp / rotation<BR><BR></FONT></DIV>
<DIV><FONT size=2>The coordinates in the sample are UTMs and the
rectangle is a rectangle, just rotated. I guess what I am looking for is
a quick and easy way to pull the subimage with a rotation applied,
maybe.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>These are UTM's, but they really could be any kind of
coordinate.</FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ed@topozone.com href="mailto:ed@topozone.com">Ed
McNierney</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=gdal-dev@remotesensing.org
href="mailto:gdal-dev@remotesensing.org">gdal-dev@remotesensing.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, August 19, 2003
11:10 AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [Gdal-dev] Warp /
rotation</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=591090817-19082003><FONT face=Arial color=#0000ff
size=2>Dear Wizard -</FONT></SPAN></DIV>
<DIV><SPAN class=591090817-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=591090817-19082003><FONT face=Arial color=#0000ff
size=2>The problem is that your "rectangle" isn't a rectangle!
You seem to be trying to reproject your image - can you describe the
input and output projections you're using? Those numbers make it
look like your input data might be in UTM (but it could certainly be
something else), but what is your desired output
projection?</FONT></SPAN></DIV>
<DIV><SPAN class=591090817-19082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=591090817-19082003> <FONT
face=Arial color=#0000ff size=2>- Ed</FONT></SPAN></DIV>
<DIV><SPAN class=591090817-19082003>
<P><FONT size=2>Ed McNierney<BR>President and Chief
Mapmaker<BR>TopoZone.com / Maps a la carte, Inc.<BR>73 Princeton
Street, Suite 305<BR>North Chelmsford, MA
01863<BR>ed@topozone.com<BR>(978) 251-4242 </FONT></P></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> Geographic Wizard
[mailto:geowiz@shaw.ca]<BR><B>Sent:</B> Tuesday, August 19, 2003
12:58 PM<BR><B>To:</B> gdal-dev@remotesensing.org<BR><B>Subject:</B>
[Gdal-dev] Warp / rotation<BR><BR></FONT></DIV>
<DIV>
<DIV><FONT size=2>
<DIV><FONT size=2>Hi, everybody</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>New to GDAL as well as using georeferenced raster
images. I am trying to figure out how to do the following, and any
help / insight would be greatly appreciated. I have put some numbers
together as an example :</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I have an image (tif/jpg/png) 5000 x 5000 that is
georef with a world file</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>2</FONT></DIV>
<DIV><FONT size=2>0</FONT></DIV>
<DIV><FONT size=2>0</FONT></DIV>
<DIV><FONT size=2>-2</FONT></DIV>
<DIV><FONT size=2>667500</FONT></DIV>
<DIV><FONT size=2>5864000</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I would like to pull a sub image of this that is
bound by a rectangle</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> 669273---------------------------
670898</FONT></DIV>
<DIV><FONT size=2>5862482---------------------------
5862538</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> 669330---------------------------
670956</FONT></DIV>
<DIV><FONT
size=2>5860859---------------------------5860910</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I would like line # 1 of the sub-image to be along
the top boundary of the rectangle, therefore it needs to be rotated
by about 2 degrees cw.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Any help would be appreciated.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Thanks,</FONT></DIV>
<DIV><FONT
size=2>Steve</FONT></DIV></FONT></DIV></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>