Hi, <br><br>Thanks for your reply. I think I have to gather more information here about the projection of the image. Currently the meta data tells me only these 3 things: <br><br>1. Origin lat lon<br>2. Size of the image <br>
3. Spacing <br><br>All I need is 4 corner points in lat / lon. Currently I am doing something like this (as an approximation) <br><br>long = centerLong + pixel_x_relative_to_origin <br><br>Thanks <br><br><br><div class="gmail_quote">
On Sat, Jun 5, 2010 at 4:20 PM, ogr user <span dir="ltr"><<a href="mailto:mrxonx@hotmail.com">mrxonx@hotmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
The answer is - it depends. If you know the image projection (Mercator?)<br>
and the precise scale of the image - it may be enough to have just one<br>
point (think - a tile from Google maps).<br>
To georeference an image in a general case (assuming the image has<br>
simple linear proportions) requires at least 2 (really at least 3)<br>
points (otherwise the system of equations won't be solvable) and more<br>
would be better. Once you solve it - you can get coordinates of any<br>
other points in the image.<br>
<div><div></div><div class="h5"><br>
<br>
Aashish Chaudhary wrote:<br>
> Hi,<br>
><br>
> I have an image with center known in lat / lon. I need to calculate<br>
> the image corners in lat / lon. I have some idea but I am wondering if<br>
> someone can share his / her knowledge.<br>
><br>
> Also is there a utility in gdal that would do this for me?<br>
><br>
> Any help is appreciated.<br>
><br>
> Thanks,<br>
><br>
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</blockquote></div><br>