Transcript Introduction to Thematic Mapping

Introduction to Thematic Mapping
SP 240 Cartography
Alex Chaucer
Dent’s Cartography
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Updates from fourth edition
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Chapter on GIS
Current literature used
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Focuses on:
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Philosophy/theory
Technology
This text maintains a focus on cartographic design
WWW sites for cartographers in appendix
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Cartography Organization
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Thematic Mapping Essentials
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Techniques of Quantitative Thematic Mapping
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Chapters 13-15
Electronic Map Production
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Chapters 7-12
Designing Thematic Maps
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Chapters 1-6
Chapters 16-17
Effective Graphing for Cartographers
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Chapter 18
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Thematic Mapping Essentials
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Introduction to Thematic Mapping
The Round Earth to Flat Map: Map Projections for
Designers
Employment of Projections and Thematic Base-Map
Compilation
The Nature of Geographic Phenomena and the
Selection of Thematic Map Symbols
Processing Geographic Data: Common Measures
Useful in Thematic Mapping
Geographic Information Systems
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Techniques of Quantitative
Thematic Mapping
7. Mapping Enumeration and Other Areally Aggregated
Data: The Choropleth Map
8. Mapping Point Phenomena: The Common Dot Map
9. From Point to Point: The Proportional Symbol Map
10. Mapping Geographical Volumes: The Isarithmic Map
11. The Cartogram: Value-by-Area Mapping
12. Dynamic Representation: The Design of Flow Maps
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Designing Thematic Maps
13. The Map Design Process and the Elements of
Map Composition
14. Making the Map Readable: The Intelligent Use
of Typographic (skipped)
15. Principles for Color Thematic Maps
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Electronic Map Production
16. Printing Fundamentals and Prepress
Operations for the Cartographer
17. Digital Map Compilation and Desktop
Mapping
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Effective Graphing for
Cartographers
18. Effective Graphing For Cartographers
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Chapter 1: Introduction to
Thematic Mapping
Some Trends
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It is easy to make a map today, but it is
difficult to make a good map
Many people make maps of dubious
quality
Less people are trained in cartography
and map design
Maps are everywhere
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The Realm of Maps
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Maps…communication devices.
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“vehicles for the transmission of knowledge”
and for analysis
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The Map Defined
Map – a graphic representation of the milieu
milieu – all aspects of cultural and physical environment
+ this also includes mental abstractions
ie. People’s attitudes
- does not include mental maps
for our purposes maps are physical objects that
can be touched
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Attitude Map
On the right, the same information presented in
psychogeographical terms. Here, a nonscientific researcher - "Dr" Annie Filme, author of
several seminal works on psychogeography,
including this caption - has encountered the
urban landscape through aimless drifting and
then recorded it as a series of impacts on her
mood.
Wigan, UK
It IS a “Map.”
From http://www.martian.fm/psychogeography.htm
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What is Cartography?
Mapmaking – the processes associated with
the actual production of maps.
Cartography – broader than mapmaking,
including the study of the philosophical
and theoretical rules for mapmaking,
including the study of map
communication.
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What is Cartography?
“The art, science, and technology of making maps,
together with their study as scientific documents and
works of art. In this context may be regarded as
including all types of maps, plans, charts, and
sections, three-dimensional models and globes
representing the Earth and any celestial bodies at any
scale.”
International Cartographic Association
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Geographic Cartography
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Distinct from other branches of cartography
Is the tool and product of the geographer
The geographic cartographer understands the
spatial perspective of the physical environment
and has the skills to abstract and symbolize
this environment
Geographic cartography is a branch of broader
science, and geographic cartographers
understand spatial methodology
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Geographic Cartography
“Show me a geographer who does not need them [maps] constantly
and want them about him, and I shall have my doubts as to
whether he has made the right choice in life. The map speaks
across the barriers of language.”
Carl O. Sauer
(1896-1975)
http://www.amergeog.org/gr/abstract/Jan96-Parsons.html
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Geographic Cartography
“In short, maps and other graphics comprise one of three major modes
of communication, together with words and numbers. Because of
the distinctive subject matter of geography, language of maps is
the distinctive language of geography. Hence, sophistication in
map reading and composition, and ability to translate between the
languages of maps, words, and numbers are fundamental to the
study and practice of geography.”
John Borchert
(1918-2001)
http://www.geog.umn.edu/Faculty/Borchert.html
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http://www.rootsweb.com/~nycayuga/maps/1882/thumbs/cover.jpg
Atlas Mapping
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Many cartographers believe that atlas
production provides some of the greatest
opportunities for thematic mapping
Could there be a published, digital atlas in the
future?
Regardless, sound design principles will
always be needed.
http://media.maps.com/magellan/Images/vd_nyc_atlas_c.jpg
http://www.prj.com/pictures/Ny.jpg
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Cartography and GIS
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A “blurred” boundary
There is great ease in the thematic display of
socioeconomic data in a GIS
GIS “assumes no knowledge of cartographic
methods nor any fundamental ideas about
good design principles”
Basic “wizard” created maps in GIS often don’t
offer the best thematic cartography
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Kinds of Maps
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General-Purpose Maps
Thematic Maps
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Qualitative
Quantative
Mental Maps
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General-Purpose Maps
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Reference Maps
Examples; Topo Maps and Atlas Maps
http://newyorksearchandrescue.org/maps/Sands%20Point%20topo%20map%202.gif
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Thematic Maps
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Allow you to view the spatial distribution
of phenomena
A “map designed to show particulars
features or concepts”
Qualitative
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To show the spatial distribution or location of kind
Quantitative
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To display spatial aspects of numerical data
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Mental Map
1. mental maps of how we interpret what's
around us often don't match reality
http://www.trainer.org.uk/members/theory/process/mental_maps.htm
http://www.hydro.com.au/education/discovery/images/concept1.gif
"a mind map consists of a central word or
concept, around the central word you draw
the 5 to 10 main ideas that relate to that
word. You then take each of those child
words and again draw the 5 to 10 main
ideas that relate to each of those words."
http://users.edte.utwente.nl/lanzing/cm_home.htm
http://www.subk.net/maps/belvideremap.jpg
http://blog.livedoor.jp/gallery163/1f601d25.jpg
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Thematic Map Components
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Must have two important elements
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Base Map
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To provide locational information to which the thematic
overlay can be related
Thematic Overlay
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Should include only enough information to communicate the
maps message
Design Strategies: Simple and Clear
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Thematic Map Components
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Must have two important elements
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Base Map
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To provide locational information to which the thematic
overlay can be related
Thematic Overlay
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Should include only enough information to communicate the
maps message
Design Strategies: Simple and Clear
Spatial Information Technology Center
Map Scale
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The amount of reduction that takes place when going from real
world dimensions to the new mapped area on the map plane
The ratio of map distance to earth distance, 1:25,000
Large Scale vs. Small Scale
http://www.rcss.org.uk/How%20to%20find%20us/how%20to%20find%20us.htm#Small%20scale%20street%20map
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Cartographic Abstraction and
Generalization
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Choosing the right abstractions for the
map’s purpose
Involve
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Selection - choosing early in the design
Classification - which objects go into groups
Simplification - smoothing lines, etc.
Symbolization - symbols to represent real items
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Cartography: Art or Science??
The art in cartography is the cartographer’s
ability to synthesize the various
ingredients involved in the abstraction
process into an organized whole that
facilitates the communication of ideas.
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Thematic Map Design
Map Design
The aggregate of all the thought processes that
cartographers go through during the
abstraction phase of the cartographic
process. It involves all the decision-making.
Involves intellectual and visual processes.
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Ethics in Cartography
How to Lie with Maps
“The purpose of this book is to promote a
healthy skepticism about maps, not to
foster either cynicism or deliberate
dishonesty. In showing how to lie with
maps, I want to make readers aware that
maps, like speeches and paintings, are
authored collections of information and
are also subject to distortions arising
from ignorance, greed, ideological
blindness, or malice.”
M. Monmonier
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Codes of Ethics
1. Always have a straight forward agenda, and
have a defining purpose or goal for each map.
2. Always strive to know your audience (the map
reader.)
3. Do not intentionally lie with data.
4. Always show all relevant data whenever
possible.
5. Data should not be discarded simply because
they are contrary to the position held by the
cartographer.
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Codes of Ethics
6. At a given scale, strive for an accurate
portrayal of the data.
7. The cartographer should avoid plagiarizing;
report all data sources.
8. Symbolization should not be selected to bias
the interpretation of the map.
9. The mapped result should be able to be
repeated by other cartographers.
10. Attention should be given to differing cultural
values and principles.
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