CheetahTraj

Overview

The source code of CheetahTraj.

Prerequisites

• JDK 1.8
• Maven
• Dependent jars are in lib directory.

Files

Calculate VQGS:

• src.main.java.vqgs.vfgs.PreProcess.java: Pre-process for the original dataset.

• src.main.java.vqgs.vfgs.VFGS.java: The VQGS algorithm mentioned in the paper. Store all the result into static files.

• src.main.java.vqgs.app.VFGSColor.java: The VQGS+ algorithm with color attribute mentioned in the paper.

• src.main.java.vqgs.app.ScreenShot.java: get the screenshot of the result, the figures are all in the data/figure_result.

• src.main.java.vqgs.util.PSC: All the config information need, including the default file path.

Others:

• src.main.java.app.TimeProfile.java: run and speed up the render with GPU.

• src.main.java.index.SearchRegionPart.java: Build up the index and store the result into a file.

Datasets

We use three datasets in our work:

• GPS data for taxis in Portugal.
• GPS data for taxis in Shenzhen, China.
• GPS data for taxis in Chengdu, China.

The paths of the data(part) are data/porto_5k and data/shenzhen_5k, if you need the full dataset, please contect with us.

Run the program

Parameter usage:

--color, -c :Choose the render type: color or not, not color by default
--dataset, -s DATASET :The dataset path
--datatype, -t DATATYPE :The data type, including Shenzhen data(0) and Portugal dataset(1)
--delta, -d DELTA :The delta in VQGS+, 64 by default
--help, -h :Show the help
--rate, -r RATE :The sampling rate in VQGS/VQGS+, 0.005 by default
--vqgs, -g VQGS :VQGS/VQGS+ calculation result directory path

• Calculate the VQGS, VQGS+ and VQGS+ with color data:

File: src.main.java.vqgs.StaticCal.java

javac StaticCal.java
java StaticCal -s <dataset file path> -d <delta> -r <rate>

• Run the demo:

File: src.main.java.vqgs.app.VFGSMapApp.java

javac VFGSMapApp.java
java VFGSMapApp

The demo is coming with the data of Porto for total 5k trajectories, keyboard interrupt:

key	function
p	save the current screenshot
o	print current location
1	show the full dataset
2	show the result of VQGS without color
3	show the result of VQGS with color
4	show the random result
d	increase the delta value
a	decrease the delta value
s	increase the rate value
w	decrease the rate value
esc	quit

• Get all the screenshot:

File: src.main.java.vqgs.app.ScreenShot.java

javac ScreenShot.java
java ScreenShot -s <dataset file path> -g <VQGS/VQGS+ file directory path>