For those interested in aerial archeology I also heartily recommend what Roger Agache did in (mostly) Northern and Central France starting with the 1960s. His aerial photos helped discover hundreds of locations for Roman-era villas and castra among other very interesting things. The website documenting his work can be found here [1], and for example aerial photos of Gallo-Romanic structures can be found at this link [2] (the website looks like it hasn't been updated in quite some time but it's still functional)

[1] http://www.archeologie-aerienne.culture.gouv.fr/en/

[2] http://www.archeologie-aerienne.culture.gouv.fr/en/