Existing methods for segmentation by edgel linking are based on heuristics and give no guarantee for a topologically correct result. In this paper, we propose an edgel linking algorithm based on a new sampling theorem for shape digitization, which guarantees a topologically correct reconstruction of regions and boundaries if the edgels approximate true object edges with a known maximal error. Experiments on real and generated images demonstrate the good performance of the new method and confirm the predictions of our theory.