Abstract: A method for processing in a computer a plurality of digital images stored in the computer. The digital images are from respective photographs (301) of a geographic region. The photographs were taken from different directions. The method includes displaying the images (311) and upon selecting an image point in an oblique image, synchronizing a corresponding image point in the digital images so that the selected image point in the first image and the corresponding synchronized image point in other images have substantially identical world coordinates. The method is useful for performing a geographic measurement (319) on an oblique by selecting an image ground point below a first image point; calculating world coordinates in a vertical line segment which extends vertically from the image ground, and upon selecting the first image point on the vertical line segment, calculating world coordinates at the first image point based on the world coordinate in the vertical line segment.