Georeferencing several unreferenced image tiles

[elizabettinger]

Hello,

I have three historic map .jpgs that I want to tile together and create one rectified dataset out of.
Each of the .jpgs has margins (they are scanned maps), and some slightly overlapping information.

So far, I have georeferenced the central tile, using a set of referenced roads data I have, and rectified it.

I am trying to figure out how to georeference and mosaic my remaining two tiles to the first one.

I would be so grateful for any suggestions you can offer.

Cheers
eb

[JohnSobetzer]

You might take the collars off all the maps first.  You could clip the georeferenced one in ArcGIS and the others in a photo editing program.  Perhaps if it was fairly easy to georeference the first one you could instead clip a copy of the original and then use a photomerge from a photoediting program to put all three maps together before doing the georeferencing of them as a unit.  If you have enough overlap that might work best especially if you don't have many control points for the other two.

If you lack much overlap, or have control points for the other two maps, you could georeference them but in so doing use some cotnrol points from your currently georeferenced map where it overlaps the others to help it line up with the two you are doing.  To make for a better match you might go to second or third order polynomial.