/NeXTA_4_NGSIM_Trajectory_Visualization

a free and open source tool for visualizing vehicle trajectories using space time diagram

How to use NEXTA to visualize the trajectory

NGSIM data set

Version 1: Prepared by Xuesong Zhou and Pan Shang

About Next Generation Simulation (NGSIM)

https://ops.fhwa.dot.gov/trafficanalysistools/ngsim.htm

Category File Remark
Main program NEXTA_4_Trajectory.exe Open source NEXTA visualization tool
Input trajectories-0400-0415 Sample file from NGSIM
Input test_one_linetest_two_lines Sample file from Pan Shang, for one vehicle's trajectory
Output Trajectory.csv Export to more user readable format

Format

Each line is a record of trajectory

Please use space or comma to separate fields.

No Field Name Example 1 Example 2 Unit remark
1 Vehicle_ID 1 1
2 Frame_ID 12 13 0.1 seconds
3 Total_Frames 884 884 0.1 seconds
4 Global_Time 1113433136100 1113433136200 text you can put any value
5 Local_X 16.884 16.938 not used
6 Local_Y 48.213 49.463 feet
7 Global_X 6042842.116 6042842.012 not used
8 Global_Y 2133117.662 2133118.909 not used
9 Vehicle_Length 14.3 14.3 feet
10 Vehicle_Width 6.4 6.4 feet
11 Vehicle_Class 2 2 pax or truck
12 Vehicle_Velocity 12.5 12.5
13 Vehicle_Acceleration 0 0
14 Lane_Identification 2 2 very important
15 Preceding_Vehicle 0 0
16 Following_Vehicle 0 0
17 Spacing 0 0
18 Headway 0 0

Steps

Step 1: Open NEXTA.

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Step 2: Select menu Tools-NGSIM Tools- Active Space-Time View, and then load trajectory file for Visualizing trajectory data

Step 3:

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Main functions

  1. Display trajectories for each lane.

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In the menu Tools-NASIM Tools:

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You can choose each lane number to see the trajectory;

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  1. You can show Vehicle ID, and you can use mouse wheeler to zoom in and zoom out the display in the certain portion.

  2. You can use the mouse to click and draw a line in the space-time plate, and the NeXTA will automatically calculate the flow, density, and speed values across the line

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  1. You can show cumulative flow count and density

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You can show the space-time Density Contour

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