On 31 Aug 2007, at 14:20, [EMAIL PROTECTED] wrote: > The lower level photos are actually taken from a plane that flies a > regular > pattern back and forth across the target area.
<snip> Yes, that's how it works. Some councils used to commission coverage of their areas to coincide with the decennial census. I remember viewing the ones West Sussex had taken in about 1971 through stereo glasses and noticing the exaggerated impression of vertical dimensions they give. A rather modest Victorian gothic building on Littlehampton sea front looked just like the sort of fairy-tale castle depicted in narrowboat art. There - back on topic. Baz
