[gdal-dev] Calculate lat lon of image corners knowing center's lat lon

[Jayesh Chaudhary]

Hi,

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:

1. Origin lat lon
2. Size of the image
3. Spacing

All I need is 4 corner points in lat / lon. Currently I am doing something
like this (as an approximation)

long = centerLong + pixel_x_relative_to_origin

Thanks


On Sat, Jun 5, 2010 at 4:20 PM, ogr user <mrxonx at hotmail.com> wrote:

> The answer is - it depends. If you know the image projection (Mercator?)
> and the precise scale of the image - it may be enough to have just one
> point (think - a tile from Google maps).
> To georeference an image in a general case (assuming the image has
> simple linear proportions) requires at least 2 (really at least 3)
> points (otherwise the system of equations won't be solvable) and more
> would be better. Once you solve it - you can get coordinates of any
> other points in the image.
>
>
> Aashish Chaudhary wrote:
> > Hi,
> >
> > I have an image with center known in lat / lon. I need to calculate
> > the image corners in lat / lon. I have some idea but I am wondering if
> > someone can share his / her knowledge.
> >
> > Also is there a utility in gdal that would do this for me?
> >
> > Any help is appreciated.
> >
> > Thanks,
> >
> > ------------------------------------------------------------------------
> >
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> > gdal-dev at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
>
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