Geographical Information Systems

30 Geographical Information Systems: Trends and Technologies

generated partition, after the MapReduce job fi nishes, the main routine

renames the job input directory to relocate it under the processed directories

(line 20).

Figure 4 shows an example of the rounds that are executed by the

main routine. Each node MR

N

represents a MapReduce job. This fi gure

also shows the partitions generated by each job. Light gray partitions are

small partitions that are processed running the single-node SJ routine.

Dark gray partitions are partitions that require additional repartitioning. A

sample sequence of rounds can be: MR

1

, MR

2

, MR

3

, MR

4

, MR

5

and MR

6

. The ...