On Orbital Labeling with Circular Contours

Schematic depictions in text books and maps often need to label specific point features with a text label. We investigate one variant of such a labeling, where the image contour is a circle and the labels are placed as circular arcs along the circumference of this circle. To map the labels to the feature points, we use orbital-radial leaders, which consist of a circular arc concentric with the image contour circle and a radial line to the contour. In this paper, we provide a framework, which captures various dimensions of the problem space as well as several polynomial time algorithms and complexity results for some problem variants.