GEOG 2681:Cartography

Spring 2015Ohio Northern University

Roots of the disciplineGeo / graphy: “description of the earth.” “a science that deals with the description, distribution, and

interaction of the diverse physical, biological, and cultural features of the earth's surface”

"The science concerned with the formulation of the laws governing the spatial distribution of certain features on the surface of the earth.“

"...concerned with the locational or spatial variation in both physical and human phenomena at the earth's surface“

“…study the location and distribution of features on the Earth’s surface” [observational science: explain and predict]

GeographyOldest of the sciences?1. Herodotus: father of modern geography

• “Historia” mid-fifth century BC2. Aristotle (384-322 BC): physical geography3. Eratosthenes (276-196 BC): measures Earth circumference4. Strabo (64 BC – AD 24): “Geographica”5. Ptolemy (~AD 150) early cartographer, map maker

Geography: oldest of the sciences?

At the dawn of humankind, people made crude sketches of geography on cave walls and rocks.

These early maps documented and communicated important geographic knowledge our ancestors needed to survive: What is the best way to get

from here to there? Where is the water at this

time of year? Where is the best place to

hunt animals?

Our ancestors faced critical choices that determined their survival or demise, and they used information stored in map form to help

them make better decisions.

SOURCE: “Understanding Our World,” in Essays on Geography and GIS, ESRI 2012, p. 52.

• Carto/ graphy: [from Greek Χάρτης, khartes = papyrus (paper) and graphein = to write] is the study and practice of making maps:

• Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.

What is a map?

Mapmakers, also known as cartographers, use a variety of tools to make maps

• A map is defined as a representation, usually on a flat surface, of a whole or part of an area.

• The job of a map is to describe spatial relationships of specific features that the map aims to represent.

• There are many different types of maps that attempt to represent specific things. 

Nature of Cartography· Maps: two important functions:1. storage medium for information2. picture of the world to help us

understand spatial patterns and spatial relationships

Analog cartography: procedures of map making

Digital cartography: use of technology digital database replacing printed map, cartographic visualizations on diff.

media

Cartography Today· Shortcomings to the use of digital

technology:1. lack of data in readily useable form

software specific formats or data too specialized high costs to convert

2. lack of skilled professionals cartographic development lags behind tech. potential

3. standardization of data data quality, exchange, interoperability

· Map-making shifting from professionals map users· need to focus on non-specialists is new for

educators

Nature of Cartography

1. Maps as forms of communication2. Characteristics all maps share3. Effectiveness in thought &

commun-ication

Maps as forms of communication· Forms of knowledge representation:

¨ literacy: written language¨ articulacy: spoken language¨ numeracy: symbolizing abstractions, numbers¨ graphicacy: drawing, painting, plans &

diagrams· describing spatial relationships:

· map: graphic representation of geog. setting· cartography: is the making and study of maps

teaching skills of map use, maintaining map collections, data collection, preparing maps, charts, atlases

the map: central object that unites all cartographers

Basic characteristics of maps All maps are concerned with two elements

of reality: 1. location: position in 2-D space (x, y coordinates)2. attributes: qualities (lang.) or magnitudes

(temp.) relationships among:

locations with no attributes involved (distance/direction) attributes at one location (temps., precip., soils) location of distribution of one attribute (pop. density) locations of combined attributes (per capita

income/educ.) distances, direction, adjacency, insidedness,

patterns, interactions = topological relationships

Basic characteristics of maps All maps are reductions of reality map is smaller than the region it portrays defined dimensional relationship between map

and reality = scale scale sets limit to how much reality is portrayed or

included on the map. All maps involve geometric

transformations transform round surface to flat map or screen called a map projection choice of projection depends on how map used map referencing system = plane coordinate grids

helps calculate distances and directions coordinate systems depend on projection for accuracy.

Basic characteristics of maps All maps are abstractions of reality diversity of real world more confusing when

reduced show only necessary information

data is classified and simplified to make understanding easy

All maps use signs or symbols as a represent-ation of reality

few words as well as symbols have universal meanings

All map symbols use marks lines, dots, colors, patterns...

their selection and arrangement?

Categories of maps Almost unlimited variety of maps “maps have many functions and many faces,

and each of us sees them with different eyes” (Skelton 1972)

Problem How to categorize?

Categorize from 3 different points of view

I. classed by scaleII. classed by function, orIII. classed by their subject matter.

1. Classed by Scale Ratio of dimension of a map to reality Mapmakers can't draw maps the same size as the

area they represent; the maps would be too big. So they draw features smaller than they actually are.

What is map scale? The consistent relationship between size on a map and size

in real life is called scale.

For instance, a map may use one inch to represent what is actually 24,000 inches on earth. Mapmakers express scale as a mathematical ratio, or fraction. The unit on the map is expressed as the number one (numerator). A scale of 1:24,000 would be read as "one to twenty-four thousand."

We cannot easily visualize a value such as 24,000 inches, so maps usually not only show the scale ratio but convert the ratio to units of measurement. For example, a 1:24,000 map can also be expressed as 1 inch = 2000 feet, or about four-tenths of a mile.

1. Classed by Scale

Ratio of dimension of map to reality Small scale map = large area, very

general detail.® Around 1:50,000 or less

Large scale map = small area, greater detail® 1:500,000 or more

Medium scale map = everything in between

No clear division among the classes

2. Classed by Function

classifying maps according to function:

no clear distinction among functions of maps

Three main categories of maps:

General Reference Maps Thematic Maps Charts

General Reference Maps· Objective?

® Show locations of various features¨ water, roads, coastlines, railroads...

· Large-scale reference maps:® Topographic maps

¨ photogrammetric methods® Larger scale maps: site location/engineering

¨ great attention to positional accuracy (legal documents)

¨ Official map accuracy standards

· Small-scale general reference maps:® states, counties, countries, continents Atlases

¨ shows same as large scale, but less detail

Thematic Maps· Also known as special purpose maps distribution of single attribute or several related

® satellite cloud cover images® election results® precipitation, temperature® population® average annual income

if objective is to show location general purpose map

thematic maps tend to be smaller scale show geographic distribution over wide area (vs. abs.

location) available data > resolution to course

regional comparisons vs. site-level decisions

Charts· Maps especially designed to serve

nautical & aeronautical navigators... Maps are to be looked at, charts to be worked on

® plot courses, determine positions navigators also use general reference maps

o maritime equivalent of topographic map bathymetric map

Maps are to be looked at, charts to be worked on® plot courses, determine positions

Two types of aeronautical charts:o visual and instrument navigation

Road map is a type of chart land navigation There are few “pure” general ref. or thematic

mapso Charts have one specific function

3. Classed by Subject Matter

· Several important categories of subjects…

Cadastral maps: made to accompany the cadastre® official list of property owners & land holdings® geographic relationship among land parcels® cadastres used to assess taxes…

Maps referred to as plans:® detailed maps showing buildings, boundary

lines etc.® plans form basis for topographical map series

· Ordnance Survey of United Kingdom

Cartographic representation Principal job of cartography? Communicate environmental information

o mapping costs, accuracy, aesthetics… buto mapping effectiveness in thought &

communication

Treat the making and using of maps equally:

Cartographer’s job: enhance map users ability to retrieve information.

Map users job: understand the mapping process

Series of information transformations: collect select symbolize reading analysis interpret· cartographer’s job? ramifications of each stage of process

The Scope of Cartography• There are four “processes” in

cartography:1) collecting & selecting data for the map,2) manipulating & generalizing the data &

designing & constructing the map,3) reading or viewing the map,4) responding to, or interpreting the map.

Have be familiar with other mapping sciences:

geodesy, surveying, remote sensing, GIS cognitive sciences (human thought &

understanding), and disciplines associated with features being

mapped