This demo traces moving vehicles as they pass through geohash tiles. It also keeps track of a vehicle movements on a day to day basis. Similar to a vessel tracking or taxi application.
Contributor(s): Patrick Callaghan
Objectives
- To demonstrate how Cassandra and Datastax can be used to solve IoT data management issues.
Project Layout
- SchemaSetup.java - Sets up the
current_locationandvechiletables. - Main.java - Continuously updates the locations of the vehicle.
How this Works
This application:
-
Allows the user to track a vehicles movements per day. The location is stored in a Cassandra table.
-
Find all vehicles per tile. Tiles have 2 sizes. Tile1 is large, Tile2 is small.
-
Find all vehicles within a given radius of any vehicle.
Setup and Running
Prerequisites
- Java 8
- A running DSE cluster
- Maven to compile and run code
Running
- Setup the schema
To specify contact points use the contactPoints command line parameter e.g.-DcontactPoints=192.168.25.100,192.168.25.101'
The contact points can take multiple points in the IP,IP,IP (no spaces).
To create the schema, run the following
mvn clean compile exec:java -Dexec.mainClass="com.datastax.demo.SchemaSetup" -DcontactPoints=localhost
- Create the Solr core
To create the solr core, run
dsetool create_core datastax_taxi_app.current_location reindex=true schema=src/main/resources/solr/geo.xml solrconfig=src/main/resources/solr/solrconfig.xml
- Update vehicle locations
To continuously update the locations of the vehicles run
mvn clean compile exec:java -Dexec.mainClass="com.datastax.taxi.Main" -DcontactPoints=localhost
- Run the webservice
To start the web server, in another terminal run
mvn jetty:run
- Sample queries
To find all movements of a vehicle use http://localhost:8080/datastax-taxi-app/rest/getmovements/{vehicle}/{date} e.g.
http://localhost:8080/datastax-taxi-app/rest/getmovements/207/20200424
Alternatively, with CQL:
select * from vehicle where vehicle = '207' and day='20200424';
To find all vehicle movement, use the rest command http://localhost:8080/datastax-taxi-app/rest/getvehicles/{tile} e.g.
http://localhost:8080/datastax-taxi-app/rest/getvehicles/gcpm
Alternatively, with CQL:
select * from current_location where solr_query = '{"q": "tile1:gcpm"}' limit 1000;
To find all vehicles within a certain distance of a latitude and longitude, http://localhost:8080/datastax-taxi-app/rest/search/{lat}/{long}/{distance}
http://localhost:8080/datastax-taxi-app/rest/search/52.53956077140064/-0.20225833920426117/5
Alternatively, with CQL:
select * from current_location where solr_query = '{"q": "*:*", "fq": "{!geofilt sfield=lat_long pt=52.53956077140064,-0.20225833920426117 d=5}"}' limit 1000;
- Remove the schema
To remove the tables and the schema, run the following:
mvn clean compile exec:java -Dexec.mainClass="com.datastax.demo.SchemaTeardown"
