GIS Outputs

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					               GIS Presentation and Output
                                --        charts
                                --        maps




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9/2/2009 Ron Briggs, UTDallas   POEC 6381 Introduction to GIS
                           Presentation: Charts
       •    charts can be used to display                   Area     Bar
            tabular data.
       •    the types of charts available in
            ArcView are typical of these
            available in GIS desktop systems
       •    most systems have dynamic (as
            opposed to static) charting:                Column       Line
            charts automtically updated as
            data in underlying tables
            changes:
       •     6 types in ArcView: area, bar,              Pie
            column, line, pie, scatter                               Scatter



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9/2/2009 Ron Briggs, UTDallas        POEC 6381 Introduction to GIS
                            Presentation: Maps
       What‟s a map?
       "a representation, normally to scale and on a flat
         medium, of a selection of material or abstract
         features on , or in relation to, the surface of the
         earth.”
                  International Cartographic Association

       A spatial model of the real world, but differentiated
         from it by:
                   abstraction, focus, simplification, symbolization
                   scale, projection, and purpose

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9/2/2009 Ron Briggs, UTDallas         POEC 6381 Introduction to GIS
                            What‟s in a Map?
 • Abstraction
       – Imaginary features (i.e. political boundaries) as well as physical features
       – Past, present, and future (archaeological sites, current, and planned roads) features
 • Focus
       – Selection and classification of features in real world to include in the map
 • Simplification
       – Simplification of complex features such as coastlines
       – Exaggeration of features that are too small to show at the scale of the map
 •    Symbolization
       – Use of symbols or graphic to represent classified objects (e.g. church)
 • Scale
       – The ratio of distance on a map, to the equivalent distance on the earth's surface.
 • Projection
       – Representing curved surface of the earth on a flat plane. Distortion is inevitable.
 • Purpose
       – To describe, measure, communicate/persuade
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9/2/2009 Ron Briggs, UTDallas           POEC 6381 Introduction to GIS
                                  Types of Maps
      1. Planimetric (e.g municipal base map)
            A map designed to portray the horizontal positions of features; vertical
              information is specifically ignored.
      2. Topographic (e.g. USGS 7.5 minute quads)
             A map designed to portray features on the surface of the Earth, including
               relief (elevation), hydrography, and cultural features.
      3. Cadastral (e.g municipal parcel map)
             A map representing boundaries of land parcels, ownership, land use,
               valuation, and other related information.
      4. Image (e.g LANDSAT image „map‟)
            A map representing a remotely sensed picture or reflection of all or part of
              the Earth's surface
            – may or may not be orthomorphically correct.
      5. Thematic (see next slide for types and examples)
            – A map used to visualize spatial relationships and patterns among information
              pertaining to some theme or concept (e.g. income)

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9/2/2009 Ron Briggs, UTDallas             POEC 6381 Introduction to GIS
                    Types of Thematic Maps
     Thematic Map: A map used to visualize spatial relationships and patterns
       among information pertaining to some theme or concept (e.g. income)
                » Choropleth map: uses zones or polygons to display information using shading, dot, density, or
                  other techniques.
                      – e.g population change, ethnicity distribution
                » Proximal (dasymetric) map: shows zones of constant attributes, such as soil type or vegetation
                  (similar to choropleth except that data determines boundary lines; no pre-defined polygons)
                      – e.g zoning, soil map
                » Isopleth map (contour or isarithmic) : shows a contiuous three dimensional surface such as
                  elevation using lines connecting points of equal value (contours).
                      – e.g elevation, travel time contours from a point(s), land values,
                        income
                » Point (dot) or symbol map: shows information relating to specific points using marker sysmbols
                  whose size and/or frequency relates to magnitude of phenomena
                      – housing sales, code violations, crimes



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9/2/2009 Ron Briggs, UTDallas                 POEC 6381 Introduction to GIS
        Making Better Maps: some general principles
   • keep it simple, but don‟t rely on software defaults
   • show only the area under study (e.g. if Texas, don‟t show AK or LA
     counties): use small insert map to show relative location
   • Plan for final printing/publication scale
        – allow for size reduction (e.g. for report or journal publication),
        – point symbols visually reduce at twice the rate of line features (a function of area)
   • put title at top using „thick line‟ font: serif/sans-serif; case not critical
   • map labels
        – best in serif font (letters have „tails‟), with first letter upper and rest lower case
        – place above and to the right of the feature (2nd choice: above to left)

        – use font size hierarchy to indicate relative importance: US,        Texas, Dallas
        – water features traditionally labelled in italic font
   • Create good map in black and white, then add color (not the reverse!)
        – 1 in 10 people are colorblind
        – people will xerox your map anyway

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9/2/2009 Ron Briggs, UTDallas            POEC 6381 Introduction to GIS
        Making Better Maps: color and symbolization
 • Color concepts
      – Hue:        the actual color (red, blue, etc)
      – Saturation: how much of it
      – Value:      the amount of black
      Use low saturation in background, high saturation in foreground
 • choice of shading
      Quantitative data
      – symbols should have visual progression corresponding to data values
      – for polygons, use monochromatic color ramp: same color (hue), different saturation
        or value
            » can highlight top and bottom with contrasting color if desired
            » if use different fill patterns, be sure “visual progression” is achieved
      – for point symbols, use different sizes of the same symbol
      Qualitative data
      – For polygons, use different colors (polychromatic), or different fill patterns
      – For point symbols, use same size of different symbols
 •   To create a color ramp for any two colors, hold CTRL key while selecting colors
 • be sure legend is big enough to clearly show different fill patterns

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9/2/2009 Ron Briggs, UTDallas               POEC 6381 Introduction to GIS
              Making Better Maps: some tricks to use
  •   Always include “neatline” around outside: ArcView uses this for positioning
       – Select Layout/add neatline to add neatline around outside of entire graphic
  •   Use the same theme twice (be sure to remove copy from legend)
       – e.g. place theme with thin black line on top of a copy of the theme with thick red line
       – e.g. have separate theme for outline of polygons
  •   Use buffering to create special effects (in View, select Theme/Create buffers)
       – e.g. along a shoreline, create multiple buffers then color ramp them
       – e.g.buffer within a polygon border, then save as new theme, and shade appropriately
  •   Controlling scale of maps in Layouts
       – use copy to create a second frame of identical size
       – Be sure distance units and map units are set in View/ Properties for any View used
       – Set scale option in “View Frame Properties” box (double click on frame to set this)
  •   Controlling size of point and line symbols in Layout
       – In View, double click on theme in TofC to open its Legend Editor
       – Click Advanced button, click Scale Symbols check box, type in Reference (output) scale
  •   for dot patterns, keep density constant and change size of dots (rather than
      converse): but most software won‟t do this!
  •   Color, or use fill pattern (dots or stipple) for oceans and large water bodies
  •   Use graphics design package for major customization
       – Export entire layout to graphics package
       – Use package to create a custom graphic then bring in as a picture/graphic
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9/2/2009 Ron Briggs, UTDallas              POEC 6381 Introduction to GIS