Chapter 3 Presenting GIS Data

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Chapter 3- Presenting GIS Data
Typically ArcGIS work shown as poster sized maps
or reports that contain smaller versions of
maps also tables and other pertinent
information Maps contain a number of different
elements Scales Coordinate system Symbols Dire
ctional Information Temporal information But
theses elements are not randomly thrown together
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Basic map design

• Objectives of the map
• What is being communicated?
• Who will be using it?
• Where will they be using it?
• For example, try navigating cross country using
  7.5 minute topographic maps! Its impossible!
• Then think about what most road atlases look like

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Bad
Good
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Basic map design

• Data layers to be included on the map
• Some data are appropriate
• Some data are not
• Often trial and error to see what it will look
  like
• For example, try all street names cannot be
  placed on a small scale map!
• It would make the map too busy.
• The same can be said for topographic maps and the
  contour interval for the topo lines

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Basic map design

• Planning the layout of the map
• Place data frames at appropriate locations
• Include where the legend will go
• Determine how big the map will be when finished
• The end result will be efficient and elegant maps
  as opposed to busy, impossible to read maps

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Basic map design

• Colors of the map
• Use colors that indicate levels of importance
• E.g., major roads are red, lesser roads are black
• Same can be said fort he symbols choice
• Use colors that suggest what the item is
• e.g., water is blue
• Avoid using colors that dont allow the user to
  read things easily
• Green text on blue backgrounds
• Red text against green backgrounds or vice versa
• Use an overall palette that indicates the nature
  of the data
• Bold colors to indicate importance or severity
• Pastels to indicate leisurely activities
• Avoid color combinations that make the user feel
  like killing someone because of the weird
  contrasts that dont work well together

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Basic map design

• Create the map
• Try to think about all of the factors while
  actually creating the map
• Realize there is a big advantage to using a
  computer
• If it doesnt work the way you thought, you can
  tweak it to make it better.

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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Choosing Symbols

• Earth tones are more pleasing to look at
• Greens, Browns, Cream, Blue
• Strident tones should be used sparingly
• Reds, pepto bismal pinks, fluorescent greens
  should be used to emphasize certain elements
• Blues are cool and calming
• Water, both liquid and frozen
• Browns are steady and solid
• Land, with little vegetation
• Greens denote growth
• Plant density can be shown using greens and brown

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Patterns on maps

• Avoid busy patterns
• When necessary, make them less apparent and they
  swill be more effective without being distracting

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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Good or Bad map design? Why?
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Which is Good and which is Bad design? Why?
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Coordinate systems

• We have identified a few different coordinate
  systems
• UTM
• Lat / Long
• State Plane
• We have identified that the coordinate system of
  the data frame determines how all other data sets
  are displayed in the data frame
• ArcGIS changes them on the fly and makes sure
  that the data being viewed is aligned with each
  other correctly

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Coordinate systems

• How do we choose what system to use?
• GIS will choose the original coordinates system
  based on which data set is imported first OR
• You can choose your own data set before importing
  the data
• The choice of the coordinate system affects how
  the map will look.

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Coordinate systems

• All coordinate systems have a reference datum
• Ensures a good fit of a spherical system to a
  distorted spherical object
• NAD1983 means a reference datum for North America
  set in 1983
• WGC1984 means a reference datum for the world set
  in 1984 (World Geodetic System)
• Lat Long are angular measurements meant for
  spherical shapes
• They are difficult to display as planar maps

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Lat / Long and projections

• When Lat long is imported into a map that is
  planar
• Distortion occurs in the east/west direction due
  to the planar coordinate system on the map
• The closer to the poles, the greater the
  distortion
• There are ways to minimize certain types of
  distortions with various types of projections

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Unprojected
Projected
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Cylindrical
Preserves distance and shape
Conical
Preserves distance and area
Planar or Azimuthal
Preserves distance and area
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Coordinate systems

• The type of map and the info you want to portray
  determines the coordinate system you will use and
  how its projected
• Very important for small scale maps that show
  nations or the world
• Regardless of what systems or projections you
  use, there will be distortion on these maps
• Example 1- maps that will be used for distance or
  area measurements
• Use a conic or a planar (azimuthal) projection
• Which preserve distance and area, but distort
  direction and shape
• Example 2- maps that will be used for navigation
  using a compass
• Use a cylindrical projection which preserves
  those traits on the map

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Mercator
Equal-Area cylindrical
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• Projection and data frame layouts
• Map projection influences some elements commonly
  placed in a data frame
• Small scale conic projections cannot show north
  using a North arrow Why?
• Small scale Mercator (cylindrical) maps cannot
  measure distance using a bar scale Why?

These are usually given what is known as a
graticule grid for determining location
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Graticule Grid (Lat/Long)
Reference Grid
UTM Grid