Abstract
Let S be a connected planar polygonal subdivision with n edges that we want to preprocess for point-location queries, and where we are given the probability γi that the query point lies in a polygon Pi of S. We show how to preprocess S such that the query time for a point p∈Pi depends on γi and, in addition, on the distance from p to the boundary of Pi - the further away from the boundary, the faster the query. More precisely, we show that a point-location query can be answered in time O(min (logn, 1+log area(Pi)/γiΔp2)), where Δp is the shortest Euclidean distance of the query point p to the boundary of Pi. Our structure uses O(n) space and O(nlogn) preprocessing time. It is based on a decomposition of the regions of S into convex quadrilaterals and triangles with the following property: for any point p ∈ Pi, the quadrilateral or triangle containing p has area Ω(Δp2). For the special case where S is a subdivision of the unit square and γi=area(Pi), we present a simpler solution that achieves a query time of O(min(logn,log 1/Δp2)). The latter solution can be extended to convex subdivisions in three dimensions.
Original language | English (US) |
---|---|
Pages (from-to) | 17-31 |
Number of pages | 15 |
Journal | Computational Geometry: Theory and Applications |
Volume | 54 |
DOIs | |
State | Published - Apr 1 2016 |
Keywords
- Mesh generation
- Point location
- Quadtree
ASJC Scopus subject areas
- Computer Science Applications
- Geometry and Topology
- Control and Optimization
- Computational Theory and Mathematics
- Computational Mathematics