An implementation of the satellite-stream module. It applies a transform stream to change location data to movement data – rate of change in latitude and longitude per second.

It launches a simple TCP server. The server implements the satellite-stream module and applies a transform to convert the stream of location data to movement data.

After downloading, install the dependencies from the terminal window:
npm install

In the terminal window, start the server with:
node tcp-start.js

In another terminal window, open a client with:
telnet localhost 65000

The client responds to three commands:

• start - begins the stream and prints out movement speed as changes in latitude and longitude per second.
• stop - halts the stream
• close - terminates the client TCP socket

Any unrecognized commands will echo back to client. Stop the TCP server with Option-C.

Movement.js is a factory function that produces a subclass of stream.Transform. It transforms the output from a Readable stream that writes JSON objects with a latitude <float> property and a longitude <float> property. The output of the transform is a JSON object with latitude <float> and longitude <float> properties that represent the change in degrees per second.

Currently the server works reliably with one client. The server does not track separate clients so start and stop commands will affect all stream consumers and cause erratic behavior.