Topology-Guided Vis isual Exploratory ry Analysis Harish - - PowerPoint PPT Presentation

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Topology-Guided Vis isual Exploratory ry Analysis Harish - - PowerPoint PPT Presentation

Topology-Guided Vis isual Exploratory ry Analysis Harish Doraiswamy NYU Center for Data Science Scan All Fish 2 Scan All Fish 3 TopoAngler 4 Data Exhaust from Cities 5 Data Exhaust from Cities Infrastructure Environment People 6


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Topology-Guided Vis isual Exploratory ry Analysis

Harish Doraiswamy

NYU Center for Data Science

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Scan All Fish

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Scan All Fish

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TopoAngler

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Data Exhaust from Cities

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Data Exhaust from Cities

Infrastructure Environment People

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Open Urban Data

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  • Yellow cab trips
  • ~175 million trips / year
  • Spatial-Temporal
  • 2 spatial attributes
  • 2 temporal attributes
  • Other attributes
  • Fare, tip
  • Distance
  • Duration

NYC Taxi Data

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2011 2012

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Idea: Use Topology of the Data

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Idea: Use Topology of the Data

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Exploring Features

  • Several features per time step
  • Group similar features within a larger time interval
  • Represents “macro” events
  • Similarity
  • Graph similarity: Shape
  • Persistence / Volume: Topological similarity
  • Key for each group
  • Average shape and volume
  • Efficient search

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Guiding Users towards Interesting Events

  • Properties of Macro Events

Two micro-events that occur on consecutive hours Two micro-events that occur on consecutive days An event that occurs every hour during a week Two micro-events that occur on consecutive weeks Rare occurence of these events Frequent

  • ccurance

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Rare and Interesting Features - Hourly

  • October

Halloween Parade

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Daily

  • October
  • 1. Hispanic Day Parade (Oct 9 2011)
  • 2. Columbus Day Parade (Oct 10 2011)

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Weekly

  • August
  • No. of weeks = 3
  • NYC Summer Streets

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5 Borough Bike Tour 2011 (1 May 2011) Query

5 Borough Bike Tour 2012 (6 May 2012) Dominican Day Parade 2011 (14 August 2011) Dominican Day Parade 2012 (12 August 2012) Gaza Solidarity Protest NYC (18 November 2012)17

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Frequent Features

  • Taxi hotspots
  • Filter over time

General trends Night time trends

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Frequent Features

  • Maxima: Taxi hotspots
  • Filter over time

General trends Night time trends

Using Topological Analysis to Support Event-Guided Exploration in Urban Data, TVCG 2014.

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  • Design of public spaces
  • Understand what works / doesn’t work in one city
  • Use this to improve design in another city
  • Understand properties of neighborhoods
  • Compare “activity” between neighborhoods with similar

properties

  • Compare properties between neighborhoods with similar

“activity”

How to compare cities?

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  • How do cities behave during different times?
  • Summer vs. Winter
  • Weekdays vs. Weekends
  • Data sets about different cultural communities in a

city

  • What patterns do the different communities follow?
  • How do these patterns compare?

How to analyze / compare different properties

  • f a city?

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Urban Pulse

  • Flickr activity in New York City

7:00 am

1

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Urban Pulse

  • Flickr activity in New York City

7:00 am

1

11:00 am

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Urban Pulse

  • Flickr activity in New York City

7:00 am

1

7:00 pm

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Urban Pulse

  • Flickr activity in New York City

7:00 am

1

11:00 pm

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Temporal Resolutions

  • Compute functions along 3 resolutions

Time of Day Day of Week Month of Year

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Step 1: Identify Pulse Locations

  • Set of scalar functions over time
  • Identify all maxima
  • Location of prominent pulses
  • is a high persistent maxima in at least

1 time step

  • is a high persistent maxima in at least

1 resolution

  • 1. Identify Locations
  • 2. Quantify Pulse

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Step 2: Quantifying Pulse

  • 3 Beats to quantify the pulse at each location
  • Significant Beats
  • Is the location a high persistent maximum?

Bs

  • 1. Identify Locations
  • 2. Quantify Pulse

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Step 2: Quantifying Pulse

  • 3 Beats to quantify the pulse at each location
  • Maxima Beats
  • Is the location a maximum?

Bs Bm

  • 1. Identify Locations
  • 2. Quantify Pulse

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Step 2: Quantifying Pulse

  • 3 Beats to quantify the pulse at each location
  • Function Beats Bf
  • Variation of the function values

Bs Bm Bf

  • 1. Identify Locations
  • 2. Quantify Pulse

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Step 2: Quantifying Pulse

Time of Day Day of Week Month of Year

  • 1. Identify Locations
  • 2. Quantify Pulse

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Step 2: Quantifying Pulse

B1 B2 B3 B4 B5 B6 B7 B8 B9

Rank Signature Data Oblivious

  • 1. Identify Locations
  • 2. Quantify Pulse

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Step 2: Quantifying Pulse

Compare Signature Data Oblivious

  • 1. Identify Locations
  • 2. Quantify Pulse

B1 B2 B3 B4 B5 B6 B7 B8 B9

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Urban Pulse Interface

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Use Case: Understanding Public Spaces

  • Typically classified together as being similar

Bryant Park Union Square Rockefeller Center

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Use Case: Understanding Public Spaces

Bryant Park Union Square Rockefeller Center

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  • Yellow cab trips
  • ~175 million trips / year
  • Spatial-Temporal
  • 2 spatial attributes
  • 2 temporal attributes
  • Other attributes
  • Fare, tip
  • Distance
  • Duration

NYC Taxi Data

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Work done together with Alex Bock, Theodoros Damoulas, Nivan Ferreira, Juliana Freire, Bruno Gonçalves, Mondrian Hsieh, Marcos Lage, Fabio Miranda, Claudio Silva, Adam Summers, Luc Wilson, Kai Zhao

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Topology-Guided Vis isual Exploratory ry Analysis

https://www.github.com/harishd10 https://github.com/ViDA-NYU