Shows a single day of New York taxi cab pickups animated over the course of the day
This example illustrates how to use Salt to generate TileJSON output compatible with CartoDB's Torque library. Salt features used:
- Loading and using CSV data in Spark
- Custom, non-trivial bin aggregator
- Compound tiling jobs (generates pickup and dropoff layers concurrently)
- Custom output format serialization
- Saving results to local filesystem on Spark Master
To build the example you must first generate the TileJSON data (written to the output/ directory) and then run the web app to view the results.
Tile generation is done using the code in the generation/ directory. If you plan on using the included Docker container to run the example, ensure that it's built before continuing (see root README).
Build the JAR and generate tiles in one command
salt-examples/torque-example/ $ docker run --rm -v /$(pwd)/output:/opt/output -v /$(pwd)/generation:/opt/salt uncharted/salt-examples
To run the container interactively, run:
salt-examples/torque-example/ $ docker run -it -v /$(pwd)/output:/opt/output -v /$(pwd)/generation:/opt/salt uncharted/salt-examples bash
Results are viewed through a simple web app contained in webapp/. After generating tiles, run from webapp/:
npm install
npm start
The application will be available at http://localhost:3000/