GIS for Environmental Science

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GIS for Environmental Science

• ENSC 3603
• Class 19
• 3/24/09

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Topics for Today

• Map Function
• Map Elements
• Cartography
• Cartographic Design in GIS
• Map layout and design
• Geographic contents of a map
• Cartographic Generalization

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What is a Map

• A graphic depiction of all or part of a
  geographic realm in which the real-world features
  have been replaced by symbols in their correct
  spatial location at a reduced scale.

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Map function in GIS

• Storage
• Temporary communication
• Intermediate check of data
• Final report
• To be effective a map must be correctly designed
  and constructed

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Map Elements
Back
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Visualization of Geographic Information

• Cartography - The art or technique of making maps
  or charts.
• GIS and Cartography are linked by their common
  focus on maps

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Conventional Cartography
Real World Cartographers Interpretation Map
Map readers interpretation
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GIS information communication
Real World Conceptual Data model Logical Data
model Physical Data Model
GIS Spatial
Database Spatial
Information operator Products
control
User
User feedback
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Cartographic Design in GIS

• Output can be paper maps or computer screen
• Use of Color
• Use of Text
• Symbols and Symbol Sets
• Map-to-Page transformation

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Color

• Color is made from color (hue), lightness
  (value), and the purity of hue (saturation)
• Color (Hue)
• Lightness (Value) range of light to dark
• Purity of hue (Saturation)
• Colors combine well with other variables
• Has visual attraction
• Easy to remember
• May be unnecessary
• Expensive to print

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Text

• Formed from
• Family set of similar typefaces
• Times new Roman, Arial, Impact
• Face or style the specific variation based on
  weight width and angle
• Bold or italic
• Font refers to a character set with particular
  style and at a specific size
• Times New Roman (20) Times New Roman (32)

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Symbols and Symbol Sets
ESRI, Learning ArcGIS 9 Creating Map Symobology
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Map-to-Page Transformation

• Is the placement of layer features onto an output
  medium of a specific size.
• Physical page
• Graphics page
• Map limits
• Map extent

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Map Layout and Design

• Basic map elements Information needed by the map
  reader
• Elements that are found in virtually all maps
  Map Figure, Legend, Distance or Scale, Direction,
  Sources of information and how map was processed
• Elements that are sensitive to context Title,
  Projection, Map creator, Date of production
• Elements that are used selectively to assist
  effective communication Neat lines, Inset maps,
  index maps, Locator maps.

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Map Layout and Design

• The most important information is generally
  larger and toward the upper left of the page.
• Less important elements are positioned to the
  right and down the page.
• Each map element needs to provide the essential
  function of improving reader comprehension.
• Guard against to much detail this may confuse
  the reader and make the map difficult to
  comprehend in a reasonable amount of time.

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Geographic Contents of the Map

• A good design for geographic contents contains
• Visual balance
• With other map components to improve the reading
  of the map
• Visual clarity
• Resolve spatial conflicts. This usually involves
  generalization
• Visual hierarchy
• Appropriate choice of font and symbol size

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Geographic Contents of the Map

• Visual contrast
• Appropriate use of color and patterns
• Context
• The selection of the appropriate layers to
  present in the map figure
• Effective label placement
• Important because it affects the readability of
  the map
• Guidelines for label placement Lo (2007) p. 264.

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Cartographic Generalization

• Map generalization is needed to simplify the map
  to improve readability and aesthetic appeal
• A small-scale map is usually more generalized
  than a large-scale map
• Index and locator maps can be used to orient the
  reader and reduce the size and amount of
  information in the main map figure

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Read and Do

• Read Chapter 7 in Lo (2007) especially section
  7.5 .
• Review ArcGIS 9 ESRI course Module 2
• Review progress on your Project
• Study for exam on Thursday the 26th
• Todays material will not be on the test.

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Challenges are what make life interesting
overcoming them is what makes life meaningful.
Joshua J. Marine You may forget how you behaved
when the going got tough, but others won't. Mark
Burnett