I'm not sure this is the right place to ask this question. If not please point me in the right direction.
Question: is there a way to calculate the size of, say a back yard, or the walls in a room from a picture?
Update: Let's say someone has an android or iphone where the specs of the camera were known. If I just went into my back yard and took a few pictures could I estimate the size of my backyard or any backyard just from the picture. Maybe I could draw on the image lines that delineate the boundaries of the property.