In this paper, we study the complexity of rectangular cartograms, i.e., maps where every region is a rectangle, and which should be deformed such that given area requirements are satisfied. We study the closely related problem of cartograms with orthogonal octagons, and show that this problem is NP-hard. From our proof, it also follows that rectangular… (More)
In this paper we study the problem of reconstructing orthogonal polyhedra from a putative vertex set, i.e., we are given a set of points and want to find an orthogonal polyhedron for which this is the set of vertices. We are especially interested in testing whether such a polyhedron is unique. Since this is not the case in general, we focus on orthogonally… (More)
Polyhedra are an important basic structure in computational geometry. One of the most beautiful results concerning poly-hedra is Cauchy's theorem, which states that a convex poly-hedron is uniquely defined by its graph, edge lengths and facial angles. (See Section 2 for definitions.) The proof of Cauchy's theorem (see e.g. ) unfortunately is… (More)
A famous theorem by Cauchy states that a convex polyhedron is determined by its incidence structure and face-polygons alone. In this paper, we prove the same for orthogonal polyhedra of genus 0 as long as no face has a hole. Our proof yields a linear-time algorithm to find the dihedral angles.
In this paper we describe a new, multi-graph approach for development of a comprehensive set of complexity management techniques for interactive graph visualization tools. This framework facilitates efficient implementation of management of multiple associated graphs with navigation links and nesting of graphs as well as ghosting, folding and hiding of… (More)