the Bay Area, 20,000 links • +10,000 cities in the United States • 150,000,000 links in OpenStreetMap database (world-wide) • With 15-min bracket, 96 rows in the cost table, per link, per day • Periodical traffic data update & continuous sensor data incoming
data sets • Introduced by Google in 2004 • Open source implementations: Apache Hadoop, HBase, Cassandra, Hypertable, and more http://research.google.com/archive/mapreduce.html