Summary: I/O­e#cient Point Location using Persistent B­Trees
Lars Arge # Andrew Danner + Sha­Mayn Teh
Department of Computer Science
Duke University
Abstract
We present an external planar point location data structure
that is I/O­e#cient both in theory and practice.
The developed structure uses linear space and answers a
query in optimal O(log B N) I/Os, where B is the disk block
size. It is based on a persistent B­tree, and all previously de­
veloped such structures assume a total order on the elements
in the structure. As a theoretical result of independent
interest, we show how to remove this assumption.
Most previous theoretical I/O­e#cient planer point loca­
tion structures are relatively complicated and have not been
implemented. Based on a bucket approach, Vahrenhold and
Hinrichs therefore developed a simple and practical, but
theoretically non­optimal, heuristic structure. We present
an extensive experimental evaluation that shows that on a
range of real­world Geographic Information Systems (GIS)

Source: Arge, Lars - Department of Computer Science, Aarhus Universitet

Collections: Computer Technologies and Information Sciences