LECTURE OUTLINES

INTRODUCTION

• 
  General Reference Maps
• Focus on geographic location
• Thematic Maps
• Focus on spatial pattern of attribute
• Base map (spatial)
  • 
    Basic (original)
    Derived (borrowed) maps
               scale problems
                distortion due to projections
    
• Attribute data (theme)
  • 
    choroplethic
    isarithmic
  • prism map
    scatter symbol
  • icon symbol
    point or dot map
    variable width flow (line)
    proportional symbol (usually circle)
    false relief
    3-D frame map
    cartogram
    
• Map parts
  • 
    Points
    Lines
    Areas
  • Volume
    Text
    
Legend and other map parts
• 
  key to symbols
  date produced
  data of data
  author/publisher
  scale
  arrow
• inset maps
  

PROJECTIONS

• Globe
• Latitude / Longitude
  • 
    Sexagesimal scale (degrees, minutes, seconds)
    Decimal Degrees, with south and west as negative numbers
    • (e.g., Chicago as 41.82, -87.62)
  • 
    Distortion of Sphere (datum)
  • Reference Elipsoid (oblate spheroid)
  • Geoid effect of gravity differences
  • Distortion by projection
  • 
    Shapes true -- conformal
    Areas true -- equivalent
    Direction true -- azimuthal
    Distance true -- orthographic

  Cylindrical
  Conic
  Planar
  Homosoline

  Great Circle, Rhumb Line
  Show graticule on map?

• • Replaces north arrow
  • Helps to align labels
  • 

Map Design and Map Composition

• 
  Managing the Visual Hierarchy
• size and choice of symbols
• contrast, coordination in value and chroma, and hue
• coordination of fonts, line weights, fills
• avoid green/red combination for small features
• layers, levels and placement
• coordination of map elements
• title: Theme first, date
• legend: key, arrow, scale, source, author, map choices, projection
• Aesthetic Appeal
• compact placement of title, legend, supplementary information
• visual depth (shadows, overlapping)
• consistency of style
• optical center of graphic
• Visibility, clarity
• • If used as grayscale, design in grayscale
  • Weaves instead of dithering if printed poorly
  • line width difference of .15 inch easily noticed
  • at 18 inch reading distance, black line not less than .006 inch
  • black dot on white field not less than .04 in, from 18 inches reading distance
  • text not less than 6 points in size
  • symbol-key association should be obvious (e.g. not too many fine shades of fill)
  • two black dots no less than .003 inches apart
• optical illusions
  • appearing complementary colors
  • green/red conflict -- color blindness
  • closure
  • apparent scaling
  • "cognitive" cartography
  • 

COMPUTER FUNCTION

Resources and function


• Local drives, networked drives, unix account, http folder
  Operating systems: Windows vs. UNIX
  Storage devices
• • diskette, CDR, CDRW, DVD, jumpdrive, UNIX account
    
• Binary system -- "switches" of 0's and 1's
• File size: bits, bytes, kilobyte, megabyte, gigabyte, terabytes
  Speed: megahertz and gigahertz, baud (e.g., 5.6k modem)
  
• File management
  • Saving files
    Changing folders and drives
    Creating folders
    Renaming files
    Copying/moving files
    Reading file type and file size
    Backing up work in progress
• 
  UNIX accounts
  • Setting up an account
    http directory with "setup"
    briefcase with mkdir
    Moving files to/from account
• 
  E-Mail -- your choice
  • Send me an e-mail TODAY
    • With an asterisk if you want graduate credit
  • YOUR NAME in capitals in subject line
  • From your preferred account
  • Special concerns or information
    
• Browser Navigation
  Finding images
  Saving images
  
• Editing images
  • Lview
  • • crop
    • change format
  • • 

RASTER GRAPHICS

• pixels/bits/cells
• tesselation
• satellite images
• photographic images
• standard formats
  • 
    .tif  .jpg  .gif  .bmp  .pcx
    4-bit, 8-bit, 24-bit, 32-bit
    87a vs. 89a .gifs
    interlaced
    compressing raster files
    Lview for conversions
• 
  Windows' Paint
• 4-connect fill
• adjusting color, brightness, contrast, etc.
• dithering
• antialiasing
• Resizing, Resampling
  
• Sources for base maps
  • 
    try the Perry-Castaņeda Library's outline maps
    also search Google.com's image engine
    Copyright considerations

CHOROPLETHIC Theme

Easy, recognizable thematic type -- common
• Available data for geographic and administrative units
  • City governments
  • School districts
  • Census units
  • Planning Districts
  • Zip codes
  • etc.
    
• Data
• derived data, not aggregate
  • Derived = Standardized = Relative = Adjusted
  • Aggregate = Counts = Totals
    
    
Base map
• size of units
• numberof units
  spatial cues, recognizability
  
• Fill
  • Colors
  • grayscale
  • patterns
  • weaves
  • avoid using white and black fills
  • dithering can cause a problem
• 
  Classed vs. Unclassed
  • Classed requires intervals/categories
  • Unclassed -- unique fill for each value
• Number of ranges
  • variation in data array
  • ability to distinguish differences in fills
  • single map or series
• 
  Range breaks
  • 
    Quantiles (visually appealing)
    Equal Intervals (assumed and usually best method)
    Natural Breaks (may be most "honest")
    Logrithmic (when data are skewed)
    Mean and Standard Deviation
  • 
    Continuous vs non-continuous ranges
    

CENSUS DATA

• Nested Geographies
  • country
  • state
  • county
  • tracts
  • block groups
  • blocks
  • block face
  • street address
• places
• urbanized areas
• metropolitan statistical areas
• Attribute data
  • population
  • housing
  • FIPS coding
  • where to get data for 2000

Mapping Point Phenomena

Location of Points
• known x, y coordinates
  geocoding to address ("address matching")
  polygon centroid
• distributed within polygon
• Similar technique to choroplethic, but uses aggregate data
  Best when data are discrete
  Choice of symbols or icons - usually a dot
  
• Point value - number of things represented by a symbol
  • should be rounded (100 not 97)
    rule of thumb -- 3 dots in most sparse area
  • rule of thumg -- begin to coalescence in densest area
    accuracy for each mapped polygon: within one half of dot value
    • (unless portions of dots/icons are shown)
    • dot value no more than twice smallest important value
• symbol size
  • adjust to create the coalescence
  • white edge can be useful when coalescing
  • clone tool is useful to control symbol size
• symbol placement
  • random
    dispersed
    clustered around known regions
    interpolated based on adjacent polygons
    in columns and rows
  • borders and dots do not represent area
    determining number of overlaps
• Areal unit mapped
  • smaller the area, more accurate geographically
    larger the area, the more accurate numerically
    • because potential error is 1/2 dot value per polygon mapped
  Legend
  • dot value
  • statement of potential error
  • process statement
  • representative distributions
• 
  Hint: The scattered dot theme can be used in combination with other cartographic themes.
   
   

Proportional Symbol Theme

• Symbol proportional to datum
• Symbols used
  • Circles --works well with pie charts
    Squares
    Spheres
  • Icons --clever multivariate symbols
        Multivariate symbol
        Eight-variable symbol
        Four-variable symbol
    Chart
• 
  When to choose proportional symbols
  • Ratio data
    Aggregate data -- USUALLY
    Derived data -- occassionally
    When there is quite a lot of variation
• Perception of circle size vs. reality
  • Absolute vs Apparent scaling
• Size and overlap
  Fills and edges
  opaque or transparent
  
  Make a cartogram with proporional circles, (also see the interactive version)
  • proportional circles for many subunits
  • outline larger units
  • remove subunits' circles
• Britain example
• 
  Formula for Proportional circles
  Key options
  
  Compare to range grading

ISARITHMIC THEME

• Isolines
  • contour (isoelevation)
    • slope and aspect
  • isotherm
  • isohyet
  • isobar
  • isogloss
• Isoplethic -- represents area data at centroids
  • derived data (e.g. per capita income)
• Isometric -- data collected at points
  • single sample data (e.g. temperature)
• Data requirements
  • continuous
  • vary predictably between known points
  • wide distribution of points
    • especially around edges
• Methods
• Triangulation
  Linear estimation using known points
• Primary and secondary interpolation 123456
  • primary (grid estimates)
    secondary (e.g. smoothing)
    
• Interpolation algorithms
  • Inverse Distance and Shepard's Method are similar: fast but create "bulls eyes"
    • Smoothing reduces "bulls eyes," particularly with Shepard's Method
  • Kriging, very common, best method for very small data sets (less than 10)
    • attempts to express trends, e.g. ridge vs. series of peaks
    • krigging and radial basis functions are similar; both good under 250 points
  • Minimum curvature generates smoothest possible surfaces and is fast
    • fastest method for 1,000 or more points. Widely used in earth sciences.
  • Polynomial Regression (planar slope) identifies large trends but loses local information
  • Triangulation not effective with 10 or fewer points.  Fast, yields angular results.
    • represents data well between 250 and 1,000 points
• Anisotropy implies a preferred direction of influence
  Search ellipse may be simple, quadrant, or octant
  Grid density is user-defined
  Exacting
      Honor datum falling on intersection
  Smoothing "uncertainty" factor
      reduces the influence of outliers
  Power (influence declines with distance)
• Other issues
• Choosing contour intervals
  • always equal interval, unless halves are necessary
  • rounded numbers
• Labeling contours
  • enough to interpret interval
  • in - line placement
  • on horizontal segments
• Contour fills
  • optional
  • quantitative
  • fill without edge?
• Hachures
  • change in direction of slope
• Show data points on map
  • sometimes labeled with known values
• • ideally, interpolation settings as well
• 3D map
  • z-dimension rendered in vertical
  • overlay of maps
  • perspective vs. orthogonal view
  • visibility of axis labels
    

COLOR

• Aspects of Color
  • Hue  ("color")
    • qualitative differences
  • Value (dark/light)
    • quantitative differences
  • Chroma (saturation)
    • quantitative differences
  • Example
    Color Cubes -- in particular look for the Munsell model
    
• Color in digital environment
  • Bit size and palette size
    2 to the fourth power = 16 colors (4-bit)
    2 to the 8th power = 256 (8-bit)
    2 to the 24th power = 16,777,216 (24-bit, "millions of colors")
    2 to the 32nd power = 4,294,967,296 (32-bit, "billions of colors")
    Palette limits depend on user's hardware/software
  • conversion by Save As... or by mode
    • conversion may be irreversible
  • RGB combinations 0 (black) to 255 (white)
    • additive: depends on light source
    • primary colors, overlap to create secondary: cyan, magenta, yellow
  • CMYK
    • subtractive: based on light-absorbing quality of ink on paper
    • used for printing using color separation "four color process"
  • HSV
    • one value for hue, one for saturation, and one for value
  • A 6X6X6 cube "no dither" color page for Netscape (displays only 216 colors)
    
• Color combinations
  • 
    Contrast: field and ground
    • affects the visual hierarchy
  • Complementary colors
    Simultaneous contrast
    Color blindness (red/green)
• Associations
  • Blue = water, cool, wet
    Red = danger, bad, warning, hot
    Green = fertile, low, moist, vegetation, good
    Yellow = dry, hot, desert
    White = missing information, very high (snow)
    Black = text, borders, important
• 
  Working with color
  • Numerically, from palette, or with slide controls
    • Hue Saturation Value adjustment (control all three)
  • Contrast enhance (stretch darks, move midrange, and change lights)
    Log enhance (lighten darks without affecting lights)
  • Change palette type
    • watch for "palette shift"
  • Resampling
  • Fixing antialiasing
    • Fixing an antialiased .jpg outline map using just Paint
      owner.gif -- (to demonstrate on)
  
  Try a program simulates colorblindness on your image
  Color blindness test

DATA TYPES

• Qualitative -- difference in type
  • alphanumberic or numeric --nominal, categorical, values (e.g., male=1, female=0)
• Quantitative -- difference in amount
  • Integers for discrete data which comes "in wholes" (e.g., population)
  • Real numbers for continuous data, with portions (e.g., population density )
  • Sequential values for ordinal, rank (e.g., 1st, 2nd, 3rd, largest city, or quantiles)
    • weak ordering -- paired ranks
    • complete ordering -- unique ranks
• Interval numbers have regular distance between values, but no true 0 ( e.g., temperature f)
• Ratio numbers have a meaningful 0 (e.g., distance)

Hint: Cartographic symbols for points, lines, and areas can show quantitative and qualitative differences

TYPOGRAPHICS

• Purpose of text
  • Titles
  • legend
  • legend values
  • labels
    • distinguish between object categories
  • comments
  • text boxes
• Text usually black and often on top of visual hierarchy
  • usually nothing crosses over text
• Fonts (typefaces)
  • ascender/descender, x height
  • serif (finishing strokes: bracketed, square, wedge)
    • ease of read
    • quality loss in digital environment
  • x-height
  • shading
  • weight
• Style
  • Italix for commentary / water bodies
    • never "skew"
  • Underline for emphasis / capital cities
  • Boldface for importance or visibility
  • Size for importance
  • measured in "points"
  • 72 points "block size" is one inch
  • 6 pt. minimum
  • never distort (stretch in one dimension only)
  • Color
    • usually black but
    • color can be used as symbol (e.g. blue for water bodies)
    Edge/fill
    • usually no edge, solid
  • Case (upper / lower)
    • uppercase appears larger, but more difficult to read
• Font families
• mixing fonts -- usually no more than 2 families
• Fancy fonts -- can be useful for title, decoration
  • easily overdone
• • Dignity -- Oldstyle typefaces
  • Order -- Conservative typefaces
  • Power -- -Bold sans serif
  • Grace -- Italics or scripts
  • Precision -- New sans serifs and slab serifs
  • Specific emotions -- Unusual, artistic fonts
  • Confusion, disorganization -- mixture of many fonts
• Placement
• Points
  • offsets to corner, not aligned with symbol
  • Upper and Lower Case
  • parallel to graticule esp. if graticule is visible
• Line
  • parallel to line
  • offset from line
  • if curved, along one smooth curve
  • for rivers, italix in direction of flow if possible
  • on horizontal section, if possible
  • words may be kerned for long linear features
  • consistent break angle
• Area
  • inside or outside area
  • Always UPPER CASE, especially for countries
  • kern letters to fill area
• Titles and legend
• Title usually highest on visual hierarchy
  • often appropriate for a carefully selected fancy font
  • Title should emphasize the theme, not the location
• Other conventions
• Water bodies are always italicized
• Text size/font consistent for similar features, when possible
  • kerning is permissable for area features
  • underlining capital city names is common
  • If polygon labels don't fit, consider abbreviating before shrinking size
  • If text it too small for linear features, consider using all capitals
• text size differences of 34 percent easily seen
• Finding and installing free fancy fonts
  • Free downloadablefonts
  • beware -- they may be location dependent
• Standard map style used by the Economist
• Interesting observation about spelling

Conventional Symbology

• Coastal areas or water bodies
  • vignetting
  • icons (boats, waves)
  • stippling
  • form lines
  • fountain fill
  • sharpened contrast
• Topographic map symbology
• see this link
• Mountains
  • shaded relief map
  • repeating symbols
  • polygon area
  • contours
• Rivers
  • winding line
  • variation in line width
  • blue
  • run under other features (e.g. roads)
• Land areas
  • green, pale yellow
  • gray for areas out of study area
  • avoid deleting adjacent land masses
  • double edge at coast

DIGITIZING -- not covered in 377
Coordinate systems
    world coordinates
    digitizer coordinates
    screen coordinates
Resolution vs accuracy
Registration
    number and location of points
    location of error
    types of registration
Snap-to distance
Determining number of nodes
    digitizing curves
    stream mode
    points at junctions
Placement of points
Types of polygons
    simple
    adjacent
    perforated
    embedded
    fragmented

© Erick Howenstine -- Geography & Environmental Studies 2004
Northeastern Illinois University: (773) 442-647 FAX:(773)442-56XX Email: E-Howenstine@neiu.edu

not to be used without permission