ADMITTED STUDENTS MASTERCLASS: �TELL A STORY WITH �A SIMPLE MAP

PRESENTED BY DR. ANTON ROZHKOV

May 2, 2025

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RESEARCH QUESTION TO SOLVE

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RESEARCH QUESTION TO SOLVE

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RESEARCH QUESTION TO SOLVE

Research Question: Where were rats clustered in NYC in 2025?

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Why spatial analysis?

• Identify patterns and relationships between rat populations and their environment
• Further develop research and overlay with the presence of food sources and potential areas of risk
• Develop localized, targeted, and efficient pest management strategies

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Why this analysis matters?

• Can help identify and address potential health and sanitation risks posed by rats
• Inform effective pest control measures to protect public health and infrastructure

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Tools/products

What are we going to learn in this demo?

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• Open data
• Data wrangling and aggregation
• Data visualization (hexagons in 2D and 3D)

INSIGHTS FROM (FUTURE) NEW YORKERS?

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How many rats per person are in NYC?

(based on reports on rats)

Your responses:

INSIGHTS FROM (FUTURE) NEW YORKERS?

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Where rats in NYC are located (clustered)?

Your responses:

DATA

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Open data portal:

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https://data.cityofnewyork.us

https://opendata.cityofnewyork.us

DATA

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DATA WRANGLING AND EXPLORATORY ANALYSIS

• We need to explore data (.csv), have a sense of it, and make a selection (only year = 2025)
• It could be done in any data management software (Excel, ArcGIS, QGIS, R, Python, etc.)

# import pandas - one of the most popular data wrangling packages

# bring our data in, store it as a dataframe

# view first 10 data rows

# view the data distribution

# view the data distribution in non-scientific notation

# divide the “date” into 3 new columns

# check columns type

# convert column ‘year’ into the date/time format

# check columns type again

# make a mask with a selection, year = 2022

# check the data distribution for the selection

# export the selection as a new .csv

# number of reported rats per person

GEOGRAPHY

The Science of Our World:

Helps Organize Everything

We Know

What

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When

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Where

Source: ESRI UC 2024 Plenary Session

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Source: ESRI UC 2024 Plenary Session

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Source: ESRI UC 2024 Plenary Session

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GIS IN OUR LIVES

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Apple Maps | Google Maps

Apple AirTag

GPS Navigator in car

GEOGRAPHIC INFORMATION SYSTEMS/SCIENCE

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Computer mapping?

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Yes

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It is a set of technologies for representing and analyzing information in a spatial way

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GEOGRAPHIC INFORMATION SYSTEMS/SCIENCE

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GIS is a set of technologies for representing and analyzing information in a spatial way

• G – Geographic – we can capture, store, analyze, and represent spatial or geographical data
• I – Information – hardware, software, and data to understand phenomena and make decisions about it; data is spatially referenced
• S – Systems / Science
• S – Systems – the technology, a tie from the information to the geography in a seamless operation
• S – Science – the concepts and theory

MAPS – THE LANGUAGE OF GIS

Communicating…

Providing Clarity…

Making the complexity

Content and Context

And Valuable Insights

Of Our World More Understandable

Image source: ESRI UC 2024 Plenary Session

And Helping Us Think Differently…

Through Patterns, Relationships, and Systems

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SPATIAL ANALYSIS IN GIS

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• Spatial analysis in GIS involves examining geographic data and relationships between features to uncover patterns, trends, and insights that can inform decision-making and problem-solving
• There are many subscription-based and free software (ESRI ArcGIS package, QGIS, Mapbox, etc.)

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• ArcGIS Online is ESRI cloud-based software to create and share interactive web maps
• “Software as a Service” principle (SaaS)
• Easy to create web maps and share them (embedded in other web pages)
• Access via web, mobile, desktop
• https://www.arcgis.com/index.html

ADD DATA TO GIS

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• We need to put data from .csv to the map

CREATE A NEW MAP AND ADD DATA

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n = 6,211

DATA AGGREGATION (1|2)

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Irregular zoning (existing geographical units)

Neighborhood Tabulation

Areas (NTAs)

Community District

Tabulation Areas (CDTAs)

…and many others (blocks, block groups, counties, etc.)

US Census Tracts

DATA AGGREGATION (2|2)

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Regular zoning (same shape and same size)

Square (fishnet) grid

Hexagon grid

Triangle grid

WHY HEXAGONS?

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Image sources: https://media.npr.org/assets/img/2013/05/13/honeycomb-2_wide-49ae2c6ec87d4b4092881baf81e2de967926cba5.jpg; https://www.zmescience.com/feature-post/hexagon-shape-nature-physics-13092021/

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WHY HEXAGONS?

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• they tessellate to form a regular and continuous grid
• hexagons reduce sampling bias due to edge effects of the grid shape (due to the low perimeter-to-area ratio of the shape of the hexagon)
• all neighboring hexagons have the same spatial relationship with the central hexagon
• the geometry of hexagons is well-structured to represent curves of geographic features that are rarely perpendicular in shape, such as rivers and roads
• the distance between the centroid of a hexagon to all neighboring centroids is the same in all directions, and more neighbors are included in the calculations for each feature if you are using a hexagonal grid (for example, in Hot Spot analysis)

HEXAGONS IN GIS

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Aggregate points tool

FINAL MAP WITH HEXAGONS

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HOTSPOT ANALYSIS

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3D MAP WITH HEXAGONS

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RESEARCH QUESTION TO SOLVE: SUMMARY

Research Question: Where were rats clustered/seen in NYC in 2025?

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• Two main clusters:
• Manhattan: Upper West Side, Harlem, and the northern part of Central Park
• Brooklyn: Bushwick, Bedford–Stuyvesant, and Crown Heights

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Not that bad!

Tools/products

What we used in this demo?

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• Open data
• Data wrangling and aggregation
• Data visualization with hexagons

Other potential areas to explore: (1) change over time (between years and between months within one year), (2) learn about socio-demographical and built environment status to guide public health measures, �and (3) overlay with the presence of food sources and waste management strategies

DEPOSIT DEADLINES

Submit Your Deposit and Accept Your Offer

To confirm your enrollment in our incoming class, please accept your offer of admission and pay your non-refundable tuition deposit by following the steps below. This deposit is credited toward your first semester's tuition bill.

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THANK YOU!��Q&A

DR. ANTON ROZHKOV, DIRECTOR OF CUSP MS PROGRAM

ANTON.R@NYU.EDU