[Gdal-dev] Help handling image with gcp.

[Stephane Routelous]

> Alternatively you could build an approximate geotransform (the same as it
> would use for a warp) from the GCPs.  This can be accomplished with the
> function GDALGCPsToGeoTransform().  Note that you will need to pass
bApproxOK
> as TRUE.

Hi Frank,

is that different than using 
void* transformer = GDALCreateGCPTransformer(...)
followed by 
GDALGCPTransform(transformer,...) for the 4 corner points and from those
points computing the transformation with
	georef[0] = m_upperLeftX;
	georef[3] = m_upperLeftY;
	georef[2] = 0;
	georef[4] = 0;
	georef[1]= (m_lowerRightX - m_lowerLeftX)/((double)m_nSizeX);
	georef[5]= -(m_upperRightY - m_lowerRightY)/((double)m_nSizeY);
?
In this case, there is no approximation ?
Am I wrong ?

Thanks,

Stephane