Patent ID: 7116843

Claim:
A method for communicating a digital image over a network, comprising the steps of: storing a digital image on a server computer; maintaining on a client computer stored image blocks comprising portions of said digital image that have been downloaded from the server computer to the client computer; in response to a request by a user of the client computer for a given view, comprising a particular image portion at a given resolution, performing the steps of computing the residual area of the view resulting from subtracting out from the view the intersecting portions of stored image blocks, and, if the residual area is positive, downloading from the server computer the residual portion of the view at the given resolution; partitioning the residual portion of the view into the minimum possible number of rectangles and downloading these rectangles from the server computer, wherein the operation of partitioning the residual portion of the view into the minimum possible number of rectangles comprises recursively executing, for the initial view and each subsequent subview, a procedure that tries to find a first stored image-block intersecting the view, and, if one is found, partitions the residual area of the view into the minimum possible number of rectangular subviews, and, if none is found, treats the entire view as a rectangle to be downloaded from the server computer.