Geog 205:

Gateway to Geography

Topic 02:

Geographic Representations

Overview of topic

• How we see the world is dictated by our culture

and experiences

• How we represent the world is dependent on our

culture and experiences

• How we interpret the world is influenced by how

others have shaped our opinions

• Technology has changed our world view

Geog 205 (Fall 2014) 2

Part I:

Introduction to Geographic

Representations

Geog 205 (Fall 2014) 3

Representations

System of symbols and images that enable

communication (sharing of meaning) and

understanding.

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Geographic Representations

• Among the oldest and most important forms of human

knowledge

– graphical (maps and pictures)

– verbal (oral or written)

• Key issues:

1. What to represent

2. How to represent it

• Problems can be approached from different perspectives

• Knowledge is power

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…con’t

• Maps/oral/written representations are not

objective forms of knowledge

– Hidden agendas and meanings – sometimes

unintentional, sometimes not

“… read between the lines of the map...to discover the

silences and contradictions that challenge the apparent

honesty of the image. We begin to learn that cartographic

facts are only facts within a specific cultural perspective.”

Harley (1989, 3)

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Imperfect knowledge

• We do not know everything!

– Our universe is infinitely complex and we have

imperfect knowledge

• Scientific knowledge is a “work in progress”

– Often many ideas compete

– Disagreement/debate necessary for progress

– Constant change – cultural perspectives and

approaches

• Seldom can we establish who, or what, is

“correct”

– New information is often needed to resolve issues

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Part II:

Distortions of Space

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Map Scale

• The amount of reduction from a globe the same

size as the Earth

– Cartographic scale – how much a map is reduced

from the original (how much zoom)

– Geographic scale – how big something is

• The distinction is important

• A small scale map is used to show large scale

features

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Spatial elements distorted on maps

• Shape and angles

– conformal

• Area

– equal area

• Distances

• Location

• Detail

– linked to map scale

– choice of cartographer

– “place distortions”

• Not possible to

preserve area and

shape on a flat map

(except a globe)

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1:50,000 1:25,000

Map scale, areal coverage and detail

1:12,500

Large scale map – shows smaller area with more detail

Small scale map – shows larger area with less detail

Choice of scale depends on purpose and technology

Choice of scale determines the amount of generalization (distortion)

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Scale and symbology

12

Modified from Heywood et al (2006), Fig 2.11

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Latitude and Longitude

• Latitude

– Reference is equator

– Ranges from 0-90 degrees N and S

• Longitude– No natural reference point

– Reference (prime meridian) at the Royal

Observatory at Greenwich England (0° Long)

– Ranges from 0 - 180 degrees E and W

• Graticule

– Arrangement of lines of latitude and longitude

on a map

Slo

cu

m e

t a

l. (

20

04

), F

ig 7

.313Geog 205 (Fall 2014)

Google earth image

showing Alaska

Google earth image

showing Brazil

Brazil8 500 000 km2

Alaska1 700 000 km2

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Source: Robin Poitras

Which is larger?

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Spatial distortions and maps

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Source: Robin Poitras

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Source: Robin Poitras

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Mercator (and variants)

• commonly used

projections

• Conformal

• Basis for most

topographic maps

Geog 205 (Fall 2014)

Source: Robin Poitras

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Part III:

Distortions of Place

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It is all about perspective

“Luke, you're going to find that many of the

truths we cling to depend greatly on our own

point of view.”Obi Wan Kenobi - Starwars: Episode VI - Return of the Jedi (1983)

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What is your view of the world?

Photo: D. Sjogren

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Mental maps

• Everyday notions about spatial location

• Based on our sensory experience and memory

• Google maps and streetview

– merging personal sensory experience with technology

• We navigate the world at ground level (our

experience)

– informed (or misinformed) by technological advances

– Who controls the representations?

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Cognition and representations

• Cognition/cognitive processes– Perception, thought process, prior experience and

memory

• Cognitive bias and representations– Attaching importance

• proximity or familiarity

– Cultural biases• how we interpret information

• choice of how to represent – choice of words or map type

– Why do certain symbols work on maps?• culturally significant – know your audience

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Symbols that work – know your audience

Slocum et al. (2004), Fig 4.4

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Politics of representation

• Place filtered through representation

– Media / popular culture

– Personal / cultural interpretations

• Challenges

– Authorship

• Who makes representations

• In whose interests – what is their agenda

– New ways of seeing (awareness)

– New ways of acting

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Part IV:

Technology and our “Global View”

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Data/information/misinformation

• Online access to a plethora of geographic data

– Raw and manipulated data in data repositories

– Interactive sites for mapping

– Navigation

• Communication systems enable near real-time

reporting (informal and formal)

– Dramatically changing our ability to learn about other

places and people

• But, it comes at a price

– Who controls the information flow?

– What are we not being told?

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Questions for the critical user

1. What is the information you are accessing?

– Where did it originate?

2. What were the objectives/biases of the creator?

– How has it been manipulated, and why?

– Who benefits?

3. Is the data “correct” or “current”?

4. What technology is working behind the scene

and what are its limitations?

– What are limitations of data collection?

– Statistical manipulation/classification techniques –

appropriate?

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Google Maps on smartphone

• What information is

necessary for this to work?

1. Location information for the

traveler

2. Image that shows the

landscape

3. Data about the location of

roads and how they are

connected

4. Destination address and

location

A. Global Positioning System

B. Remote Sensing

C. Geographic Information

Systems

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A. Global Positioning Systems

• USA system consists of:

– Satellites (> 24) at ~11,000 miles altitude

– Ground receiving/transmitting stations

– Receivers (your car GPS, smartphone, hand held

GPS)

GPS constellation

http://www.gps.gov/multimedia/images/

• Satellite launch ongoing (first group 1978-85)

• Known as NAVSTAR (Navigation System for

Timing and Ranging)

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How it works in a nutshell

• Satellites broadcast a

time coded signal

• The times it takes for the

signals to reach receiver

are used to determine

distance from the

satellites

• Distance from satellites is

converted to location

(latitude and longitude)

http://www8.garmin.com/aboutGPS/waas.html

http://neethutv.wordpress.com/

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Help! My car is lost!

• Errors caused by:

1. Clock errors

2. Atmosphere

3. Multipath

4. Orbit errors

5. # satellites available

6. Satellite location in sky

7. User error

• Intentional

1. USA government *

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Other Navigation systems

• Russia – GLONASS

– Satellites launched after 1982

• European Union – Galileo

– Operational after 2018

• India - Navigational Satellite System

– Operational by 2014

• China - Compass Navigation System

– Satellite launches are ongoing

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B. Geographic Information System (GIS)

• A GIS is a computer system

used for storage, retrieval,

mapping and analysis of

geographic data

• Involves extension of

database systems to

accommodate spatial

information analysis and

queries

• Primary system used to

manage geospatial

informationSource: unknown, showing different data

layers in a GIS

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Some capabilities of GIS

• Input, conversion and display spatial information

– Various data is all referenced in the same geographic

space for further analysis

• Analyze geometry and spatial relationships

– Many applications in transportation and environmental

fields

• Cartographic and Geovisualization

– By integrating different types of information into maps

and digital representations help make informed

decisions

• Use for modeling and forecasting

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GIS – two data formats

• Both can be used to

represent geographic

features

• Vector data:– stored as points, lines, and

polygons

– to each feature, attach a

table of attributes

• Raster data:– Stored as pixels

– Attributes (e.g. colour) stored

as values of the raster grid

Heywood et al. (2006), Fig 3.9

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Resolution

• Spatial Resolution

– Smallest thing that can be

identified (resolved)

– In images usually refers to the

“pixel” size

• Dependent on the sensor

and the distance from object

• Resolution and scale are

closely linked, but they

are not the same thingHeywood et al. (2006), Fig 3.10

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Cartographic v. Geographic Scale

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C. Remote sensing

• Definition:

– “the science and art of obtaining

information about an object, area, or phenomenon through the analysis of data acquired by a device that is not in contactwith the object, area, or phenomenon under investigation.” Lillesand & Kieffer

– AKA Earth Observation (EO)

• Passive

– System records energy that comes to it

• Active

– System sends out energy and records

what comes back

http://hosting.soonet.ca/eliris/remotesensin

g/bl130lec13.html

Source: unknown (shows Passive remote sensing)

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The Electromagnetic (EMR) Spectrum

• Electric and magnetic fields traveling at ~ 3 x 108 m/s

• Emitted by all objects above ~ -273°C

• Basis for remote sensing – sensors measure EMR

http://bc1.lbl.gov/CBP_pages/educational/WoB/index1.htm

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Orbit types

• Sun-synchronous

– Typical of satellites with environmental applications

– Examples: Landsat series, Terra, Aqua

• Geostationary

– Typical of meteorological and communication

satellites

– These orbits allows a satellite to pass over a

section of the Earth at the same time of day

– Examples: GOES series, Anik series

• Near Polar Orbiting

– This allows the satellite to see virtually every part

of the Earth as the Earth rotates underneath it

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Types and applications of EO imagery

• Different spatial resolutions for different problems

– Low resolution used for large areas – high resolution

used for small areas

• Different sensors detect different parts of the

EMR spectrum

– give different/complementary information

• Some problems require specific combinations of

resolution and wavelength

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GeoEye-1 – Yushu, China (15 Apr 2010) Post Earthquake (0.5 m resolution)

http://geoeyemediaportal.s3.amazonaws.com/assets/images/gallery/ge1/hires/yushu_china_04_15_10.jpg

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IKONOS - Natori, Japan (12 Mar 2011)Post Earthquake (1 m resolution)

http://geoeyemediaportal.s3.amazonaws.com/assets/images/gallery/ge1/hires/natori_japan_03_12_11.jpg

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Landsat 5 – Calgary (early 1990s)Colour Infrared (30 m resolution)

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Data source: Landsat TM – processed by D. Sjogren

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GOES 11 – East USA (26 Aug 2011)Hurricane Irene (1 – 4 km resolution)

http://goes.gsfc.nasa.gov/goescolor/goeseast/hurricane2/color_lrg/latest.jpg

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Radarsat and Envisat (Radar)

http://www.asc-csa.gc.ca/eng/satellites/radarsat2/featured_antarctica.asp

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Representations – dangerous waters!

• Geographic representations

– Human decisions on what and how

– Human choices are always accompanied by bias

• Cultural undercurrents

• Agendas not always obvious (intentional or not)

• Technology and representations

– Creates a false sense of “accuracy” or “correctness”

– The same limitations apply even if the representation

came out of a computer

Lesson: Don’t take anything at face

value, read between the lines.47Geog 205 (Fall 2014)

Applications in our Geospatial Revolution

Geog 205 (Fall 2014) 48

Episode 1 http://www.youtube.com/watch?v=poMGRbfgp38

Episode 2 http://www.youtube.com/watch?v=GXS0bsR0e7w

Episode 3 http://www.youtube.com/watch?v=OePOK6nzcaY

Episode 4 http://www.youtube.com/watch?v=9F7z9LLYxf8