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<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>
<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 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>
<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 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>
<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 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></BODY></HTML>