1. A computer-implemented method comprising: obtaining an image of a rendered document that includes text; determining a two dimensional geometric shape based at least on a first location in the image of the rendered document of a first space between a first pair of consecutive words, a second location in the image of the rendered document of a second space between a second pair of consecutive words, and a third location in the image of the rendered document of a third space between a third pair of consecutive words, wherein the first space, the second space, and the third space are not all included on a same line of text in the rendered document; generating a document signature based on the two dimensional geometric shape; and generating a query for an electronic document that is a counterpart to the rendered document, based at least on the document signature.