I have an overlay grid of images (252 total) from 1938 and another set from 1949 (245 total) that I am trying to rectify over our present day county. For the 1938 set, they range in size from ((6480-7200) x (5160-5900)). It seems that the difference in time period has really left me with only partial roads as good reference points. Even then, when I match three corners, the fourth is always off. The distortion of adding that fourth control point invariably changes the positions/angles of the roads. This prevents the road from appearing to rest over the newest imagery in a way that would not appear off.
I am having a frustrating time trying to make it work. My question is, can dividing the imagery into fourths help with the process or would improvement only be marginal? In the 38's, it appears that most of the county was centered around agricultural and the reference points are just not available.
Any helpful advice would be appreciated!