Why are satellite photos upside down?

July 25, 2011 5:18 AM

Why are satellite photos upside down? When looking at satellite pictures of cities in the northern hemisphere on Google maps, buildings that are leaning away from me are leaning towards the bottom of the screen. This gives me the impression that I'm upside down. The feeling is very strong despite my poor description of it. Is there a particular reason satellite pictures are oriented this way?
posted by hoca efendi to Computers & Internet (8 answers total)

Do you mean that the perspective of the photo is such that the photos look like they were taken from the north side?
posted by devnull at 5:27 AM on July 25, 2011

I'm not sure that's true for all areas. Looking at, for example, Toronto the buildings appear to be "leaning" left and slightly up, like the image was taken from east southeast. I assume it just depends on where the satellite is in it's orbit when the picture is taken.
posted by ghharr at 5:57 AM on July 25, 2011

It all depends on the position of the satellite taking the picture. Often you get two images from different satellites at different angles on the same map which makes the effect even stranger.
posted by alby at 6:02 AM on July 25, 2011 [5 favorites]

It's just the position of the satellite and probably position of the sun, it all affects the perspective of how you view the pictures...
posted by fozzie33 at 6:04 AM on July 25, 2011

they try to correct images by http://en.wikipedia.org/wiki/Orthophoto
posted by fozzie33 at 6:06 AM on July 25, 2011

I think most of the photography is actually done from planes, not satellites. This increases the effect quite a bit.
posted by Akke at 7:46 AM on July 25, 2011

+1 to Akke. The photos you are looking at are taken by plane. A tipoff sometimes comes from the credits at the bottom of the map. For instance, this picture of the buildings in Back Bay, Boston:

http://maps.google.com/maps?q=boston,+ma&hl=en&ll=42.35827,-71.058809&spn=0.003825,0.008256&sll=51.500154,-0.126235&sspn=0.003223,0.008256&gl=us&t=h&z=18

credits MassGIS and Commonwealth of Massachusetts EOEA (Executive office of Environmental Affairs), meaning it was probably a plane flown for a GIS survey of the city. These are usually done for anything from tax parcel purposes to environmental reasons (drainage, sewerage, etc).
posted by scolbath at 11:18 AM on July 25, 2011

Response by poster: Well, that was helpful, thanks everyone. So I get the "upside down feeling" because some pictures are taken from the north. But as you say, pictures are taken from many different angles.
posted by hoca efendi at 10:18 PM on July 25, 2011