Title
Optimal spanners for axis-aligned rectangles
Abstract
The dilation of a geometric graph is the maximum, over all pairs of points in the graph, of the ratio of the Euclidean length of the shortest path between them in the graph and their Euclidean distance. We consider a generalized version of this notion, where the nodes of the graph are not points but axis-parallel rectangles in the plane. The arcs in the graph are horizontal or vertical segments connecting a pair of rectangles, and the distance measure we use is the L1-distance. The dilation of a pair of points is then defined as the length of the shortest rectilinear path between them that stays within the union of the rectangles and the connecting segments, divided by their L1-distance. The dilation of the graph is the maximum dilation over all pairs of points in the union of the rectangles.We study the following problem: given n non-intersecting rectangles and a graph describing which pairs of rectangles are to be connected, we wish to place the connecting segments such that the dilation is minimized. We obtain four results on this problem: (i) for arbitrary graphs, the problem is NP-hard; (ii) for trees, we can solve the problem by linear programming on O(n2) variables and constraints; (iii) for paths, we can solve the problem in time O(n3 log n); (iv) for rectangles sorted vertically along a path, the problem can be solved in O(n2) time, and a (1 + ε)-approximation can be computed in linear time.
Year
DOI
Venue
2005
10.1016/j.comgeo.2004.09.001
Comput. Geom.
Keywords
Field
DocType
following problem,shortest path,optimal spanner,manhattan distance,geometric spanners,arbitrary graph,maximum dilation,axis-aligned rectangle,euclidean distance,isothetic rectangles,euclidean length,geometric graph,time o,dilation optimization,linear time,shortest rectilinear path,linear program
Geometric graph theory,Discrete mathematics,Combinatorics,Shortest path problem,Distance,Directed graph,Graph bandwidth,Distance-regular graph,Lattice graph,Mathematics,Widest path problem
Journal
Volume
Issue
ISSN
30
1
Computational Geometry: Theory and Applications
Citations 
PageRank 
References 
5
0.51
4
Authors
7
Name
Order
Citations
PageRank
Tetsuo Asano11448229.35
Mark De Berg21497153.24
Otfried Cheong359460.27
Hazel Everett429629.68
Herman Haverkort524417.68
naoki katoh61101187.43
Alexander Wolff71017.44