Digital Earth Exam 1

Lectures 1-7

What makes a map?

Shows an area larger than we can see, things we cannot observe directly, and highlights features of greatest interest

Reference Map

General-use map showing geographic boundaries and features

Thematic Map

A map that focuses on specific features or characteristics related to a theme

Babylonian Map of the World

• Oldest map of the world according to Manson

• ~600 BCE

• Babylon in center surrounded by ocean

• includes rivers, mountains, and surrounding cities and regions

• Mythical account of creation in text above map

Lascaux Cave Art

• in France

• 600+ paintings

• Lots of animals, maybe hunting scenes

• earliest known human artistic expressions

Neolithic Catalhoyuk

• ~6900 BCE

• town in front of erupting volcano

• undetermined if it is a map or not, might be interpretation of space

• houses could be figurative representation of “town”

European Prehistoric “Maps”

• Mont Bego, Fontanalba Valley, France

  • Skin Hill Village and Mont Bego Village

  • symbols for hut, path, enclosure & land use

• Giadighe, Valcamonica, Italy

  • S shape river with streets, agricultural map

• Bedolina, Valcamonica, Italy

  • layered, complex rock carving

  • agricultural map

Babylonian Empire

• Written Law: code of Hammurabi

• distance measurement (cubits)

• knowledge of area and volume

• division of circle into 360

Babylonian Plans

• Clay tablets used to plan houses, statues, areas

• Statue of Gudea

• Map of Babylon

• Suburb of Babylon

Gasur (Nuzi) Map, Yorghan Tepe

• First map with clear orientation/system of directions

• Babylonian district bound by 2 mountain ranges, bisected by river

Plan of Nippur

• river euphrates, canals, city wall, gates, measurement text

• may be drawn to scale

Egyptian Maps

• plan of egyptian garden

  • formal, figurative map, unlikely to be accurate

• Turin Map of the Gold Mines

  • functional map for navigation

  • included roads, waterways, mountains, gold deposits

Eratosthenes

• 276-195 BCE

• Head librarian at the great library of alexandria

• 1st to calculate earth’s circumference, axial tilt, global map projection with parallels & meridians

• wrote Geography

Claudius Ptolemy

• 90-168 CE

• compiled maps and corrected accumulated errors

• revised circumference of the earth

• defined geography: graphic representation of the whole known part of the world, along with the things occurring in it

Roman Cartography

• developed by Greeks, adopted by Romans for practical use like travel, trade, military, expansion, education, propaganda

• no original contributions

• no primary source, only text descriptions of maps

Aqua Cabra Inscription

• 1st century BCE

• aqueduct plans

• waterways used for human consumption and sometimes irrigation

Groma

Surveyor’s cross to create long lines for land measurements

Centuriation

Gridding of land

Cadastral Maps

Comprehensive description of land ownership including boundaries, owners, history

Hereford World Map

• made by 3 cartographers

• commissioned by Julius Caesar

• culmination of T&O map

• meant to teach about bible

Peutinger Map

• derived from earlier map

• extremely long, covers 60,000km

• distances recorded in 4 different units depending on local tradition

Byzantine Cartography

Biblically based flat-earth maps that regressed cartography

Medieval Maps

Figurative maps used to advance religious views

T&O Map

• by Isidore Seville

• T represents 3 rivers

• Jerusalem is center of map

• East is on top (direction of paradise)

Renaissance/ Age of Exploration

• Monasteries copied documents which reached wider audience of scholars

• had to meet demand for increased global exploration

1569 Map of the World

• by Gerardus Mercator

• designed to solve navigation problems

• greatest accuracy of coastlines even though high latitudes showed great distortion

Chinese Mapping

• Non-western culture that developed their own highly accurate grid system

• Song Dynasty made the Yu ji tu Stela metal tablet engraving with cartographic grid

Fangmatan, Qin Maps

• 7 maps drawn across 4 boards

• show main river and tributaries, transportation, trees, settlements

• oldest surviving paper map found in tomb

Mawangdui Silk Maps

• south was on top

• shows main rivers, areas of military importance are zoomed in

• standardized symbolization

Al- Idrisi

• Islamic cartographer

• islamic map-making wasn’t universal

• used standard distances

1152 World Map

• made by Al-Idrisi

• south is on top, indian ocean surrounds all sides except east

• made with curved lines

• depicted 7 climates of the world

Mesoamerican Maps

• Mapa de Cuauhtinchan No. 2

• Mani Land Treaty Map

Mapa de Cuauhtinchan No. 2

• Mesoamerican

• used in land claims to argue in Spanish courts

• mythic history combined with accurate geography

• depict 7 Nahuatl tribes emerging from caves of origin and timeline

Mani Land Treaty Map

• Mesoamerican; earliest Maya maps

• round with church in center

Dublin Rail Flows Map

• modern thematic map

• lines symbolize volume of human travel

Cholera Outbreak Map

• Made by doctor John Snow in 1855

• overlaid cholera cases over water pump locations

• example of analytical mapping

Characteristics of Map and Survey Data

Attribute, spacial, temporal

GPS

• global positioning system

• Global navigation satellite systems

• first version made by US dept of defense

• form of remote sensing data

GPS System Function

• Satellite transmit spatial and temporal signals of location

• receivers interpret signals to determine location using triangulation with at least 4 satellites

El Zotz Guatemala Project

• ground survey

• used 40k points

Geocoding

attaching geographic location to address info, initiated with commercial businesses and intersections

Surveys

gather attribute data; ex. census

Sensors

can collect 3 aspects of climate data; wind, temp, precip

Metadata

Data about data; who made it, how and when it was collected, how accurate the data is, what the resolution is

Resolution

Smallest unit of area measured

Accuracy

How correct the data is

Attribution Accuracy

High sample number indicates more accuracy

Attribution Resolution

Info includes many intervals to separate data

Temporal Resolution

High sampling frequency indicates high resolution

Temporal Accuracy

Maps are up to date

Spatial Accuracy

An objects location on a map is accurate to real-world

US Decennial Census

• collects race, age, and housing situation every 10 years

• used for funding purposes by representatives and senators

• homeless people and rural housing may go uncounted

American Census Survey

• has more attributes than US Census

• taken every year

Spatial Interoperability

How well 2 datasets work with each other; spatial resolution (region, state, county, census tract, etc.)

Attribution Interoperability

Attribute categories don’t match; missing categories, same categories for different data, etc (Chinese = Asian vs Chinese = actually Chinese)

Temporal Interoperability

Using different timelines for comparison data, regions may be bound differently over time

Ian McHarg

• architect that made maps for land development

• used transparent overlays for site selection

• darker area indicated lower suitability

• mapped environmental factors like slope, surface and soil drainage

McHarg Land Use Suitability Composites

• recommended land use for State Island (urban, recreation, conservation, etc.)

• following this plan would have reduced hurricane Sandy losses in 2012

Canada Geographic Information System

• first GI system, made in mid 1960’s

• used for land use management, resource monitoring, and regulatory procedures

Roger Tomlinson

• ‘father of GIS’

• developed land classification system

Harvard Lab for Computer Graphics and Spatial Analysis

• directed by Howard T Fisher

• pioneered automated computer mapping

• created SYMAP by Jack Dangermond

Jack Dangermond

• created SYMAP to model air pollution

• founded ESRI in consulting company

• created publicly available GIS tool

5 Concepts of Mapping

• location

• direction

• distance

• space

• navigation

Location

• nominal

• absolute

• relative

Direction

• up, down, left, right, forward, back

• egocentric

• landmark

• compass directions

Distance

• nominal (abstract, nonspecific)

• absolute (use standard metric)

Space

• description of geographic area

• topology is how locations are related to each other

Navigation

• landmark knowledge

• route knowledge

• survey knowledge

Types of Data in GIS

• discrete objects: vector data

• continuous field: raster data

Application approach to GIS

treat GIS as a practical tool used to solve real-world problems, make maps, and support decision-making

Developer approach to GIS

focus on building, refining, and expanding GIS as a technology platform

Science approach to GIS

conducting research and using GIS to understand spatial relationships

Spatial Analysis

• processes create patterns

• aim to identify pattern to be able to

• identify and understand the process

Scale

how map units relate to real-world units

Projection

rendering a three dimensional earth into a two dimensional map

Types of Scales

• representative fraction (ratio)

• graphic (drawing)

• verbal (1in=1mi)

Map Extent

description of what the map encompasses; coordinates of the corners of the map (in ArcGIS)

Map Resolution

smallest unit which is measured

Coordinates

• set of 2+ numbers that specifies location in relation to reference system

• Cartesian Coordinate system: x and y axis relative to origin

• geographic coordinate system: latitude and longitude

Types of Projection Distortion

• shearing: stretching

• tearing: separations in continuous area (cuts in a map)

• compression: forced condensing

• one feature is always compromised: area, shape, or distance

Conformal Projections

• shapes of coastlines accurate

• maintains shape and angles, distorts size

• mercator projection

Equal-Area Projections

• maintains area, distorts shape

• Gall-Peters projection

Equidistant Projections

• maintains distance, distorts shape and area

• UN logo

Compromise Projections

• all properties are distorted, but not to an extreme

• Robinson Projection

Interruption Projections

• uses shearing

• reduces shape and area distortion near poles, distorts shape

• Goode Homolosine Projection

Artistic Projections

• don’t preserve anything, artistic purposes only

• Stabius-Werner Projection (heart)

European Landscape Ecology

• human-centered perspective

• cultural landscapes

• lacking nature/ecology aspects

North American Landscape Ecology

• quantitative and spatially explicit

• more ecological

• includes modeling

Landscape Heterogeneity

• differences in composition: what and how much of each land cover type

• differences in configuration: spatial arrangement of elements

Core Concepts of Landscape Ecology

• structure (diversity of elements)

• function (connections and flows)

• change

Map Elements

frame, title, background, figure, scale, legend credits

Visual Hierarchy

Western from is from top left corner to bottom right corner

Balance and hierarchy

elements should coexist without being too distracting from each other, emphasis on an element is intentional and relevant

Visual Variables

• shape

• hue (color)

• value (color brightness)

• size