The Nature of Geographic Phenomena and the Selection of Thematic Map Symbols SP 240 Cartography Alex Chaucer

The Nature of Geographic Phenomena and the Selection

of Thematic Map Symbols

SP 240 CartographyAlex Chaucer

http://images.google.com/imgres?imgurl=http://employees.oneonta.edu/farberas/arth/Images/Ambassadors/globe.jpg&imgrefurl=http://employees.oneonta.edu/farberas/arth/ARTH214/terrest_globe.html&h=957&w=911&sz=574&tbnid=MspzxUMiDwAJ:&tbnh=146&tbnw=139&start=25&prev=/images%3Fq%3Dglobe%26start%3D20%26hl%3Den%26lr%3D%26sa%3DN

Spatial Information Technology

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Geography Defined

Geography

The science that deals with the analysis of spatially distributed phenomena



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Geography and Geographic Phenomena

Geography• Both a social and physical science• Wide range of research interests• Science of spatial analysis• What? Where? Why?• Geographic inquiry: from architectural to

terrestrial, and everywhere in between



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Richard HartshorneThe Nature of Geography

“The intrinsic characteristics of geography are the product of man’s effort to know and understand the combinations of phenomena as they exist in areal interrelation in this world.”

Some chapters availableonline at:

http://www.colorado.edu/geography/giw/hartshorne-r/1939_ng/naturehome.html



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"everything is related to everything else, but relationships are stronger when they are near to one another." Waldo Tobler

http://www.geog.ucsb.edu/~tobler/index.html



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Major Themes in Geographic ResearchAreal or Spatial Association

Study of the functional or causal spatial relation between variables.

E.g. The relation of a floral shop to high rise office buildings.Forms and Processes

Study of the processes that result in spatial distribution.

E.g. The tectonic forces and the distribution and creation of landforms.Spatial Interaction

Study of the interaction/flow of people/goods from place to place.

“forces of attraction” and “friction over distance” are major concepts.

E.g. The development of road networks in response to increases in travel.Distance Decay

Study of the decreasing occurrence of events away from a certain point.

E.g. Influence of a city on a region (nodal area development)



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Key Concepts in Geography

Direction – Absolute: N, S, E, W; Relative: Deep SouthDistance – Usually: Units of Length; Relative: time, costGeographic Scale – Global, Regional, LocalLocation – Absolute: Coordinates; Relative: in relation toDistribution – Points/area; dispersed; agglomeratedLocalization – Spatial ClusteringFunctional Association – Associations cause them to occur

near eachotherSpatial Interaction – one type – spatial diffusion of people,

goods, ideasThe Regional Concept – internal homogeneity sets it apartConcept of Change – geography is dynamic, constant

transformationhttp://www.colorado.edu/geography/gcraft/notes/mapproj/gif/mollweid.gif



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Fundamental Concepts in Geography

Las Vegas 1940s



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Las Vegas 1955



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Las Vegas 1959

http://piru.alexandria.ucsb.edu/collections/sweeney/html/Fundamental_Concepts.html



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Vegas, baby, Vegas!!!

http://www.directordercenter.com/images/lasvegaspostcards/0180%20Obs%20Las%20Vegas%20Strip%20Sands%20Caesars%20Landmark%20Holidaybg.jpg



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Geography for Life

5 themes developed by 1994 Goals: Educate America

1. Location2. Place (distinguish by phys.& human characteristics)3. Human/Environment Interaction4. Movement (goods, people, & ideas)5. Regions

With these themes 18 geography standards have been developed.



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Measurement in Geography

Geographic phenomena vs. geographic data

Geographic phenomena – elements of reality that have spatial attributes; any spatial phenomena can be the subject of geographical analysis within the limits of scale

Geographic Data – facts about which conclusions can be drawn; chosen to describe geographic phenomena; associated with a spatial dimension



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Spatial Dimensions of Geographic Phenomena

http://en.wikipedia.org/wiki/Image:PetersMap.jpg

1. Point (zero-dimensional)2. Line (one-dimensional)3. Area (two-dimensional)4. Volume (three-dimensional)5. Space-time (four-dimensional)



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Spatial Dimensions of Geographic Phenomena

Spatial dimensions may depend on scale---City as a point City as an Area

http://www.city-data.com/city/Saratoga-Springs-New-York.html



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Discrete, Sequential, and Continuous Phenomena

Discrete – do not occur between spatial observations; distinguishable individual entities or counting units

Sequential – lines or linear phenomena; a

series of points or discrete elements. Roads, phone lines, etc.

Continuous – extend unbroken and without interruptions, elevation, temperature, etc.Fractional parts are allowed.



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Measurement Scales

Measurement is the “assignment of numerals to things as to represent facts and conventions about them.”

S. S. Stevens



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Measurement ScalesScale Operation Examples

Nominal Equality Numbering of players

Hardness of mineralsStreet numbersRaw scores

Temperature: CelsiusPosition, TimeStandard scores(?)

Numerosity (Counts)

Length, DensityPosition, TimeTemperature: KelvinLoudness:sonesBrightness: brils

Interval Distance

OrdinalGreater or less

Ratio Ratio



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Measurement Error

Observer Error – performance of investigator biased

Instrument Error – flaw in instrumentEnvironmental Error – study conditions play role

in measurement



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Data Sources

Three kinds of geographic data:

1. Direct Field Observation – quantitative or qualitative2. Archival Sources – aerial photos, other maps3. Those generated from Theoretical Work – predictions, projections, models

Where does downloadable geographic data fall? Is the data accurate?



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The Geographic Areal Unit

http://en.wikipedia.org/wiki/Image:PetersMap.jpg

Natural Areal UnitsGeographic elements in two dimensionsE.g. Lakes, countries, farms, cities

Artificial Areal UnitsImposed by researchers to organize data ans facilitate data collectionE.g. Regions, Metropolitan Statistical Areas (MSAs), and census tracts

Single Areal UnitsCan be used to make inferences about the aggregate

Aggregate Areal UnitsComposed of several singular areal units



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The Multidimensional Characteristic of Thematic Map Symbols

Symbol Selection Wide choices for the cartographer Based on

Logic Geographic phenomena Graphic choices

What symbol best represents what I am to show Limited by

Cartographic convention – may already be a standard symbol Audience limitations – keep it simple



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Symbol Types, Symbol Visual Dimensions, Qualitative and Quantitative Mapping

Symbol Types

Standard Point, line, polygon Volume

Symbol Dimensions Shape, size, color hue, color value, color saturation, pattern orientation,

pattern arrangement, pattern texture Location on the map

Qualitative vs. Quantitative What is there vs. how much is there

http://www.geoclip.net/img/th1.gif



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Characteristics of Geographic Phenomena and Symbol Selection

Map symbols The language of maps

“As elements in a constructed view of reality, cartographic symbols mustcommunicate differences among geographic features, functional relationships,

and relative significance” Monmonier



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Characteristics of Geographic Phenomena and Symbol Selection

Functions of map symbols

1. Portray a location and it’s neighbors

2. Causal relationships among features

3. Routes

4. Phenomena with multiple instances

5. Variation in count or magnitude

6. Variation in density

Select a symbolization plan that best portrays the appropriate concept in geography.



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Enumeration Data, Geographical Units, and Census Definitions

• Provided by federal government census• Aggregated data• Tabulated by specific geographic area• What are the geographic units?



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The United States Census

Census of Population and Housing Decennial census Since 1790 “head count” for determining the House of Representatives Single best source to geographic researchers for

broad-based demographic data socioeconomic data



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The United States Census

Census Geography The divisions and descriptions of areal entities, both political and statistical;

used to tabulate census (enumerated) data E.g. Census regions, census divisions, states, metropolitan areas,

counties, minor civil divisions, census tracts, block groups, blocks, etc. Governmental area units – established by law, really exist and are marked on the

landscapeStatistical Area Units – established merely for the convenience of enumeration and

tabulation

What are those above?



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Census Resources Online

www.census.govAmerican Factfinder

NYS Census data:http://www.nylovesbiz.com/nysdc/default.asp

Can download geographic census files and attribute tables for NYS.


Documents

The Nature of Geographic Phenomena and the Selection of Thematic Map Symbols SP 240 Cartography Alex Chaucer