On rare occasions, I have found roads and other lines on Google Earth (fences, etc.) that do not line up correctly; the road will be going straight, and then when it switches to another satellite image, the road will be shifted over to the side quite a bit. What do you think causes this? Note: If it has to do with imperfect satellite picture stitching, then how/why do these imperfections happen? :dubious:
Google earth is made up of stitched together satellite and aerial photos derived from different sources at different time periods. They don’t take any photos just for Google Earth; they compile already existing but scattered information.
Satellite photos are seldom shot from a position perpendicularly above the subject (you can observe this by looking at the shots of cities - you can often see the sides of the buildings, as well as just the roof)
As a result of this, the photos need to be adjusted - as well as adjustments for the curvature of the Earth (in general and with respect to the non-perpendicular original image). All those adjustments, plus some other more subtle ones, can add up to inaccuracies in registration of map tiles, especially as there will have been a limit on the mathematical precision of the calculations underlying them.
Plus… conventionally, all of those adjustments are done with a view to translating a curved globe into flat maps - Google is then trying to fit those flat maps back onto a curved globe.
On a related (but somewhat separate) topic, image stitching issues also occur in the street-level photographic data, but I think that has a different cause (I believe the streetview data is stitched on the basis of matching similar parts of the edges of neighbouring images) - my favourite example of this appears in Google Maps streetview (as well as its counterpart in Google Earth) - this cafe is near where I work. The sign above the door at thiscafe actually (that is, in the real world) says “Big Breakfasts’”