Extensible operations
Spatio-temporal Join Query:
./hadoop jar st-hadoop-uber.jar stjoin /indexDir<Dataset-1>/ /indexDir<Dataset-2> /Result rect:x1,y1,x2,y2 interval:t1,t2 timedistance:td,resolution spacedistance:d shape:edu.umn.cs.sthadoop.core.STPoint -overwrite
Parameters and Command | Description |
stjoin | This is the map reduce method that invokes the spatio-temporal join query. |
indexDir |
The HDFS directory where the dataset is being indexed. The directory represent the parent directory of the hierarchy spatio-temporal index |
Result | The HDFS output directory where the result will be stored. |
rect: | The spatial minimum boundary rectangle area of the spatio-temporal join query. |
interval: | The time interval of the spatio-temporal range query. The time should be in the following standard time format: yyyy-MM-dd, such as 2017-01-12. |
shape: | The shape format of should be extended from STPoint that support spatio-temporal data. |
time: |
* Optional parameters to intentionally specify a specific resolution layer to query from. For example, if space partitioning technique used in spatio-temporal index then these possible parameters could be passed [ day, week, month, year] If property not specified in the execution command line, then ST-Hadoop will decide the execution plan considering all spatio-temporal resolution indices. |
timedistance |
This is the joining condition based on the distance of time. This parameter assigned by a pair of <td,resolution>, such as td could be any integer numbers and resolution on of the following (second,minute,day,week,month,year) For example, timedistance:1,day |
spacedistance | The join condition based on space distance. Note that "d" value should be any double value in mile. For example, spacedistance:2 |
-overwrite | This flag indicate to overwrite the output directory if it existed. |