<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Thanks Jukka, that is an interesting article in its own right, and it
is relevant to historical maps too. Your solution is viable, but it
takes more work (insert corner gcp in each image), which shouldn't be
necessary, as this information is already available but is discarded by
gdal_translate. If gdal_translate could keep this information in the
target file, even when gcps have been added, everything would be fine
(and my impression is it should).<br>
<br>
Jan<br>
<br>
Rahkonen Jukka wrote:
<blockquote
cite="mid:CC197224AC75CE4DB23F739B16891B86F7324A@tikka.haapa.mmm.fi"
type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.3492" name="GENERATOR">
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"
size="2">Jan Hartmann <j.l.h.hartmann <at> uva.nl> writes:</font></div>
<div> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"
size="2">Jukka Rahkonen wrote:</font></div>
<div> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"
size="2">>> Hi,<br>
>> <br>
>> I am not sure if I understood how you trying to do the job,
but hopefully my<br>
>> task and work flow are close enough to be useful for you.<br>
>> <br>
>> 1. Let's say that the original image is in epsg:2393 and
target is epsg:3067.<br>
>> 2. I insert some ground control points in epsg:3067 with
gdal_translate and<br>
>> -gcp. Image format of the temporal output file can be GeoTIFF
but also virtual<br>
>> raster(vrt).<br>
>> 3. I warp the temporary image, now containing gpc's in
epsg:3067 projection, to<br>
>> final product using gdalwarp as<br>
>> gdalwarp -s_srs epsg:3067 -t_srs epsg:3067.<br>
> <br>
> <br>
>> Hi Jukka,<br>
>> You have described exactly what I want to do, but the problem
is that<br>
>> in step 2, inserting gcps, the georeferenced boundaries of the
file are<br>
>> lost. Eventually you get a somewhat displaced raw raster file.<br>
>> Jan </font></div>
<div> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"
size="2">Hi,</font></div>
<div> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"
size="2">That displacement could be avoided at least by inserting
manually gcp to each<br>
corner of the image. Perhaps this article gives some ideas:<br>
<a moz-do-not-send="true"
href="http://www.scangis.org/scangis2007/papers/r3_rahkonen.pdf">http://www.scangis.org/scangis2007/papers/r3_rahkonen.pdf</a></font></div>
<div> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"
size="2">-Jukka-</font></div>
</blockquote>
</body>
</html>