gis brownbag series making maps that communicate
Post on 22-Dec-2015
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Making Maps that CommunicateMaking Maps that Communicate
Most important question: communicate what?
• Share information
• Highlight patterns and processes
• Illustrate results
• Planning
• Create an interesting and visually pleasing picture
Primary goal:Primary goal:
Secondary goal:Secondary goal:
Warning:
“map creator is very much the arbiter and architect of what the map portrays”
Drawbacks of maps: Maps can lie
Making Maps that CommunicateMaking Maps that Communicate
Key points:
• Maps convey information
• Maps must be easy to use – easy to interpret
• Maps must be transportable
• Large number of people must be able to use those maps
In this context, what are the advantages of a GIS over traditional paper maps?
Making Maps that CommunicateMaking Maps that Communicate
A good map is a map that communicates wellA good map is a map that communicates well
A good map…
.. Looks good
.. Is simple and elegant
.. Is fit for intended purpose
Which of those three is the most important?
What you map will look like is determined by..What you map will look like is determined by..
1. Purpose
2. Reality (e.g. shape of a country may determine the layout of the map)
3. Available data (Is the data in raster format? Are your rivers polygons or lines?)
4. Map scale (Determines how much area is covered on a map)
5. Audience (How much knowledge do they have? Do they want summaries?)
6. Conditions where the map is used (light levels of areas where map is being used)
7. Technical limits (paper map? Paper size? Internet browser constraints?)
• Area of interest in more detail or
• Location of Map Body in smaller scale map
Map elementsMap elements
A good map is a map that communicates wellA good map is a map that communicates well
Key point for making a Key point for making a good mapgood map:
• Purpose of the map
• Show a location? Directions? Trend?
• Every map should have only 1 purpose
• Who will read your map?
Why is this important to consider?
• Target the person least prepared to understand you map’s message
• Include enough information so that this hypothetical person can understand the map
• Is anybody in the audience color blind?
About 1 out of every 20 people is colorblind.
Key points for making a good map: Key points for making a good map: AudienceAudience
• Purpose
• Audience
• Purpose
• Audience
• Size and scaleHandheld mapsHandheld maps
Handheld maps (roadmaps)• Smallest font is six points six points
• Can support complex and detailed symbology
• Keep it simple
• Simple symbology
Why, given this is a large-scale map?
Viewed from large distances
Large MapsLarge Maps
Sources: World Wildlife Fund, Wildlife Conservation SocietyAsian Bureau for Conservation, World Conservation Monitoring, and ESRI.
±
500 0 500 1,000Kilometers
Projection: Lambert Azimuthal Equal Area
500 0 500 1,000Kilometers
Projection: Lambert Azimuthal Equal Area
Existing reserves
Wildlife reserves
India
Other countries
Proposed reserves
High priority
Medium priority
Low priority
To be surveyed
India
Other countries
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A good map is a map that communicates wellA good map is a map that communicates well
• You want to direct your audience to your message
Message: Ada county has the largest
population in Idaho
A good map is a map that communicates wellA good map is a map that communicates well
Focus
• Where does the map reader look first?
• Position ….
•Experiment: write down the first number that you see...
How could you make this map better?
Better map:
Use colors to get your message acrossUse colors to get your message across
How to make a visually pleasing map…How to make a visually pleasing map…
Balance: placement of the title
How to make a visually pleasing map…How to make a visually pleasing map…
Tip: Place the title slightly closer to the elements on the map than the top of the page
• Too much white space
• Object of interest is so small that it is hard to read
• Scale is in awkward numbers
• Legend has too much unimportant information
Black and White MapsBlack and White Maps
What do you think of the legend?
• Some classes have identical coloring
• Not intuitive: color for medium burn is most intense…
Symbology: ConventionsSymbology: Conventions
Part of a 7.5-minute topo-graphic map at 1:24,000 scale produced by the USGS
Rules about:
•Colors (e.g. water is blue)
•How certain features are abstracted
•Symbols that are universally recognized
Sticking with Conventions at IDWR
You can find layer (.lyr) files on the X: drive that contain symbolization
Symbols should be intuitive
What can you tell about this map even without the legend?
Symbolizing points: Symbolizing points: QuantitiesQuantities
Earthquakes
Symbolizing points: CategoriesSymbolizing points: Categories
Use different symbols to symbolize categories
Tips for selecting colorsTips for selecting colors
• Most People can only distinguish 7 classes
• For 4-5 classes uses shades of the same color
• People interpret darker colors as “more” or “greater”
• It is easier to distinguish shades of blue or purple
• Use common sense: bright green may be lush vegetation, brown is desert, bright red is hazard