Cartography: Communicating Spatial Information Scott Bell GIS Institute.
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Transcript of Cartography: Communicating Spatial Information Scott Bell GIS Institute.
Cartography: Communicating Spatial Information
Scott BellGIS Institute
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GIS Output and Information Communication
What do we want to communicate?
How can it be communicated?
http://blogs.esri.com/esri/arcgis/2011/10/28/design-principles-for-cartography/Google: ESRI design principles
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What is Happening on a Map? Geography/Space is being simplified
Non-geographic information is being simplified
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Map Types
Let’s see what types of maps we can makeDot densityProportional/graduated symbol
choropleth
Dot Density Maps
Portraying numeric/count data with dot density
Dots coincide with enumeration area DO NOT represent location of observation
Dots represent a CONSTANT quantity Generalization is associated with aggregation
Use with quantities of observations
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Proportional/Graduated Symbol
Symbol size varies in proportion to attribute value “proportional” implies a continuous range of symbol sizes
Also called Graduated Symbol and Variable Symbol “graduated” implies symbol size is associated with a range of attribute values
Used with ratio data that has a range of values absent of outliers
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Choropleth Maps Portraying statistical data with area symbols
Area symbols coincide spatially with and represent data values for enumeration zones
Features in the same class should be similar and should be symbolized similarly
Features in different classes should be dissimilar and should symbolized differently
12Maps created by Tayyab Shah, 2011.
Thematic maps - Choropleth
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Thematic maps – Graduated Symbol
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Cartography Maps as communication Cartographic/Map elements Map Layout Cartographic Semiotics
SymbolsTypography
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Cartography as Communication Maps as visual communication
Special purpose languageGrammar and syntax
Related to graphical communication
Maps as symbolicGeneralizationsrepresentations
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Bertin, J. (1983). Semiology of graphics. Madison, Wis.: University of Wisconsin Press.
Cleveland, William S. 1985. The Elements of Graphing Data. Monterey, CA: Wadsworth.
Schmid, Calvin F. 1983. Statistical Graphics: Design Principles and Practices. New York: John Wiley and Sons.
Schmid, Calvin F. and Schmid, Stanton E. 1979. Handbook of Graphic Presentation, 2nd ed. New York: John Wiley and Sons.
Tufte, Edward R. 1983. The Visual Display of Quantitative Information. Cheshire, CT: Graphics Press.
Tufte, Edward R. 1990. Envisioning Information. Cheshire, CT: Graphics Press.
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Designing Maps Well Clarity and Legibility Figure – Ground Balance Visual Hierarchy Contrast Audience, Venue, Intent, and Format
Clarity and Legibility Easy to read
Symbols, legends, themes Colors, patterns, etc. used to differentiate distinct symbols and elements
Individual elements should be larger than required for regular vision
Focus of attention19
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Figure - Ground
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Map Layout Visual Hierarchy
Location on mapSizeProminence
Balance Experimentation Defensibility of each element
S4, Brown University22
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Cartographic Elements Elements found on almost all mapsDistance or ScaleDirectionLegendSources of information and how processed
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Cartographic Elements Selectively use elements
NeatlinesLocator mapsInset mapsIndex maps
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Cartographic Semiotics Theory of signs
Referent and symbol (or sign)
Relationship between the two Cartographers semiotic toolboxVisualOther…
S4, Brown University28
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Symbol Systems Levels of data
Nominal, ordinal, interval, ratio
Feature typesPoints, lines, areas
Symbol systems for each Typography and lettering
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Continuum of Symbols
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Typography and Text Content and Form “Colonies controlled or ruled by the Spanish Empire on the eve of the Spanish-American War”
or“The Spanish Empire in 1898”
Sans serif vs. variable font styles
S4, Brown University35
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7 Design Considerations know your subject decide on an appropriate scale decide on volume of data to be presented (esp. # of areal units)
data preprocessing (intensive data)
data classification areal symbolization legend design