[GRASS-user] Georeferencing old areal photography

[Markus Neteler]

Hi James,

On Wed, Dec 30, 2015 at 4:36 PM, James Keener <jim at jimkeener.com> wrote:
...
> I realize that not all of these scans are in the exact same orientation,
> scale, and skew and will need to use something like pHash (or anything
> suggested!) to attempt to find overlap. Part of what I'm trying to
> figure out right now is how to do the overlap with the GIS files since
> phash would only work if I tile my maps of current lines.

How about using the "SIFT" method to find GCPs and then run i.rectify
to bring them together?

Or, mosaik with SIFT, then georeferencing the resulting mosaik map to
a modern orthophoto mosaik.

Or, run each tile through i.ortho.rectify for a full approach.

And then deal with the rail lines...

Just an idea,
Markus