Transcript NR 322: Introduction to Geographic Information Systems

NR 422- Advanced GIS
Cartography
Jim Graham
Spring 2009
GIS Professionals
• Produce GIS reports, articles, posters,
and web sites that are:
– Accurate & Precise
– Astatically pleasing
– Informative
– Legal
– Include the standard cartography elements:
• Spatial data, legends, scale bars, north arrows,
regional maps, credits, author(s), and projection
& datum
• Are recognized as authors!
What is a map?
Questions
• Purpose:
– What is the map trying to communicate?
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Audience?
What data is available?
What is the schedule?
Required accuracy?
What resources are available?
– Software
– Computers
– Existing photos, graphs, maps
Maps by type
• General reference maps
– Show a variety of fixed features
– Water bodies, coastlines, roads, etc.
– Topographic maps
• Thematic or special purpose maps
– Show one attribute or relationships between
them
• Charts
– Navigation by boat or plane
Maps by subject
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Cadastral: ownership
Weather
Research
Recreational maps
Planning
Informational/Educational
Overall Style
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Antique
Political
Chart
Academic
Trail Maps
Street Maps
USGS Topographic Map Series
Levels of Quality
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Hand drawn
MapQuest
ArcMap
PowerPoint
Illustrator & Photoshop
Quark
• Media: Electronic or paper
Types of content
• Contone
– DEMS
– Photos
– Some statistical layers
GoogleMaps
• Spot color (drawings, vector)
– Points
– Polylines
– polygons
– Categorical rasters:
• Land cover
ESRI ArcMap Data Set
Map Production
• Computer Screens (CRTs, Monitor):
– Emit light in a grid
– About 100 dpi
– Red, Green, Blue
– Good for contone
• Printers:
– Place ink on paper
– Cyan, Yellow, Magenta, Black (CYMK)
– 300 to 2000 dpi
– Good for spot color
Color Theory
Light: Additive
Computer Screens (CRT)
Pigment: Subtractive
Printers
Hue
CIE Color Diagram
Color Separation
Process Color
Color Printer Process
• Get the layout right
• Test the margins on a black and white
printer
• Test the color print
• Adjust the colors until they look good
• Show it to others including target
audience
• Cut off a white border if desired
Offset Press
• Professional grade
• Large numbers of copies
– $500 for 500 copies
– Cheaper for additional copies
• Each color on a separate “plate”
• Can mix special colors
• Almost all magazines and books are
printed on offset press
Pre-Press Process
1. Talk to the printer!
2. Follow color printer process
3. Take the file and the color print to the
process printer
4. Process printer creates “photo ready
art”
5. May do a test run
6. Approve final output
Paper
• Paper is graded by “hardness”
– Newspaper
– Office paper
– “Hard” paper (Hammermill)
– Glossy paper
• Colored paper
– Dark colors rarely work with computer
printers
– Use white paper and print the background
solid
Using ArcMap with GA
Applications
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Prepare your map elements
File -> Export
Select the appropriate file type
Resolution as specified by the printer:
– With spot color: 300 to 1000 dpi
– Without spot color: 150 to 200 dpi
– Files will be big!
• Import into the other application
– Add backgrounds, callouts, redo the legend
Export File Formats
• Contone:
– JPEG
– TIFF with JPEG compression
• Spot Color, Line Drawings
– GIF
– PNG
– TIFF with LZW or run-length compression
• Combined:
– JPEG with high quality (low compression)
– TIFF without compression
Using Color
• Pastels - calming
• Saturated colors – fun, exciting
• Young:
– Red, blue, green, saturated
• Older:
– Blue, green, red, unsaturated
• Color preference varies by culture!
• 10% of men and 0.5% of women are
color-blind (poor color discrimination)
Background Color
• Sets the tone
– Black – dramatic
– White – technical
– Green – comforting, natural
– Red – exciting, danger
– Beige – soothing
– Orange, yellow – warm
• Should not be bright
• Should compliment the content
Borders
• Neat lines – contrast background:
– Light background: black
– Dark background: white or yellow
• Large regions – typically black
• Dashed for smaller subdivisons
Solid areas
• Oceans: light blue
• Regions: pastels
• Patterns: going out of style?
– Patterns of sparse vegetation, rocks, etc. are
ok.
– Hashed areas only used for special purpose
Networks
• Standard symbols for
highways, roads
• Blue with black
outlines for rivers,
black lines for
streams
GoogleMaps
Points, “Marks” or Symbols
• Standard when
available
• Easy to identify and
remember
• Size: big cities larger
National Geographic
Standard Symbols from the USGS
• http://pubs.usgs.gov/tm/2006/11A02/
Overlays
• Informational
balloons
• Photos
• Call outs
National Geographic
Labels
• Typically black or a
dark color
• Drop shadow or
“halo” to highlight on
a dark background
• Size matches
importance
National Geographic
Label Placement
• Typically horizontal
• Large roads and steams the label should
be above the feature and curve with it
• Labels in regoins can follow it’s shape
• Should always be right side up
• Should not overlap with other labels and
symbols
Positioning Guidelines
• Entirely on land or entirely on water
• Match orientation of the map
– Small scale: match parallels
– Large scale: match bottom edge
• Not curve unless needed
• If out of orientation, should have a slight
curve
• Avoid wide spaces unless needed
• Never upside down
Elements of Cartography
Label Placement
Place name
5 name 1
2 Place name
Place
4 Place name
Place
Place name
6 name 3
Place name 7
Place name 9
Place name 8
Place name 10
Elements of Cartography
Visual Variables
• Primary:
– Shape
– Size
– Orientation
– Color
• Secondary (Pattern):
– Arrangement
– Texture
– Orientation
Map Elements
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Title
Spatial Data w/neat lines
Regional maps
Scale bars
North arrows
Text: Author, data, projection, datum,
sources, descriptive
• Grid lines and margins
• Magnetic declination: navigation maps
Regional Maps
• Enough for the user to identify the area
– US map does not need regional
• Some maps need multiple:
– Global
– Regional
– Local
North Arrow
• Style should match overall map style
• North points to true north
• Must follow lines of longitude (meridians)
at the location of the arrow (ESRI does
not do this automatically!)
Scale Bars
• Who is the audience?
• What measures for distance do they
use?
• Units: Degrees, metric, English?
• Always use metric (SI) or degrees for
scientific maps
• Must be readable
• Which region does it match?
Techniques
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Classification
Simplification
Exaggeration
Generalization
Classification
• Express the salient character of a
distribution
• Similar attributes into categories
• Create “typical” attribute for an area
• Clustering
– Combining features at small scale (large
extent)
– Combine related features that are close
together
Simplification
• Must reduce the detail of the map while
maintaining it’s informational content
• Small-scale maps:
– Find points that represent clusters
– Polygons can be become points
– Multiple points can become one
Exaggeration
• Exaggerate a feature of interest
– Elevation
– City size
– Feature size
• Buildings
• Bridges
• Monuments
Generalization
• Reduces the size of the data (in bytes)
• Reduces detail
• Reduces interest in the generalized item
Composition
• Spatial data should be the focus, set the
stage, and take up the most area
(typically)
• Legends, scale bars, credits and other
items fill in the gaps
• This makes each map layout unique
• Try different arrangements until you find
the one that “looks best” (show it to
others)
Map Element Placement
• Title at the top
– Sometimes vertically on the left
– Rarely on across the bottom
• In or around the map?
– Either way it must stand out!
Title
Title
Title