Visualization of Grouping Definitions

Intuitively, a Group is a set of entities that travel together for a sufficiently long period of time.
From many formal definitions of a group, we compare four grouping definitions: The Convoys[1], Swarms[2], (Original) Groups[3] and Refined Groups[4].
All four definitions require three parameters to define a group:

We apply algorithms to compute groups based on above definitions to data sets consist of real-life trajectories.
From the results, we visualize the trajectories and integrate them in the video from the same data set.
Our visualization program is based on the work of Maurice Marx .

Grouping Information and Examples

A Moving Entity

info Head: current location of the entity, color indicates the grouping by one of the definition

Tail: previous locations of the entitiy, color indicates the grouping annotated by human

ID: unique for each entitiy

Example 1

ex1 Human annotated groups: {1,2}

Groups by a grouping definition: none

Example 2

ex2 Human annotated groups: {3,4,5}

Groups by a grouping definition: {4,5}

Example 3

ex3 Human annotated groups: {8,9}
Groups by grouping definition: {7,8,9}, {8,9}, {9,10}



Data Sets

Vittorio Emanuelle II Gallery

VEIIG

Contains trajectories of 630 pedestrians tracked in the hallway.

Parameters: m=2,ε=0.963m,δ={17,38,58}

Source: here and here

Crowds-By-Example

CBE

Pedestrian near a university building, contains 434 trajectories

Parameters: m=2,ε={1.22,1.52}m,δ={36,57,78}

Source: here and here

Grand Central Terminal Set 1

GS1

There are 2592 trajectories in this 800 frames data set. We try different sampling rate of trajectories.

Parameters: m=2,ε=0.76m,δ={10,15,20}s

Sampling Rate: 100%, 50%, and 25%

Source: here

Grand Central Terminal Set 2

GS2

There are 3313 trajectories in this 800 frames data set. We try different sampling rate of trajectories.

Parameters: m=2,ε=0.76m,δ={10,15,20}s

Sampling Rate: 100%, 50%, and 25%

Source: here

ETH Walking Pedestrian Set 1

ETH

Pedestrians entering and exiting a university building, contains of 360 trajectories

Parameters: m=2,ε=1.24m,δ={72,89,105}

Source: here

ETH Walking Pedestrian Set 2

HTL

Pedestrians in the sidewalk near the tram stop, contains 389 trajectories

Parameters: m=2,ε=0.94m,δ={20,58,96}

Source: here

References