Nota GIS - week 12
Transcript of Nota GIS - week 12
Cartographic Design
maps are the preeminent means of recording
and communicating information about
location and spatial characteristics
maps are the primary source of data input
into a GIS and are the primary product of GIS
analysis
Maps are valuable in three ways:
they are efficient ways of recording and
storing spatial information
they provide a means to analyze locational
distributions of spatial patterns
they can present findings and communicate
information effectively
To realize this potential, however, maps have to be effectively designed and presented.
As in all forms of communication, in order to present your ideas effectively on maps requires training.
unfortunately, desktop mapping programs abound and almost anyone can produce a map
One of the most useful approaches to the study of cartography is to view maps as a form of visual communication--a special-purpose language for describing spatial relationships.
The Design Process
If cartography is a form of communication,
the measure of a good map is how well it
conveys information to its readers to
enlighten, convince, or persuade.
1. Think before you draw
What is the motive, intent, or goal of the
map?
a. what do you want the map reader to learn?
b. why are you drawing the map at all?
Who is your intended audience?
– how much will they know about your subject matter?
– how much cartographic experience do your map readers
have?
Where will the map be used? reports, newspapers, atlases, web
Web Map: 200 Kb GIF file Report Map: 4 Mb TIF file
© Spatial Information Systems © Spatial Information Systems
What data are available for the composition of the
map?
– quantity & quality issues: too much or too little
What resources are available?
– equipment: printing software, printing options
– time: how much time to invest in a project; production time
drops dramatically with practice
2. The Map Composition Process
Establish the format of the final product.
– colour or black & white?
– letter-size or poster?
– stand-alone or book?
Place basic map elements.
– map
– title, scale, legend, north arrow
Place optional map elements, depending on
context.
– data source(s) & processing, projection,
cartographer, date of production, neatline, locator
maps, inset maps, index maps
Experiment with map layouts.
– maps are "read" from left to right; top to bottom
– place most important details near top-left; least important details near bottom-right
there should be a defensible reason for the placement of each map element
less is more
– too much detail or too complex a layout can confuse readers and work against effective communication
3. The Cartographer's Palette
features of the real world are abstracted and
symbolized on maps as points, lines, and areas
cartographers use symbols to represent location,
direction, distance, movement, function, process,
and correlation
a tremendous amount of practice and skill is involved
in choosing effective strategies for symbolization
Strategies for Symbolization - Spatial Symbols
Text & Type Symbols
Content
– concise, carefully formulated captions and
annotations make a tremendous difference to a
map
– avoid content redundancies between titles,
legends and annotations
– avoid using abbreviations unless you are certain
your audience will be familiar with their meaning
Form
– sans serif fonts can be scanned more rapidly by
most readers
– readers of text in serif fonts seem to retain more
of the information
– use of bold, light, italics, BIG, small, UPPER
CASE, lower case, Mixed Case, and colour can
be used to indicate different degrees of
importance
– too many fonts (and sizes) can potentially confuse
the reader
typographers try to use no more than four fonts or font
sizes on a given page
– on professionally produced maps:
font, size, and case are used very carefully to encode
text
the text is used to group information into useful
categories that reflect the theme of the map
Position
Choropleth Symbols
the whole point of displaying the data cartographically is to generalize the data to facilitate the search for spatial patterns
by generalizing and simplifying the data, however, the cartographer may just as easily obscure subtle gradations in the underlying distribution
thus, the cartographer must always try to strike a balance between remaining true to the underlying data distribution and generalizing the data sufficiently to reveal intrinsic spatial patterns
after the data have been divided into
categories, you must use the visual
resources at your disposal to symbolize
them on the map
4. Design Ideals vs. Software Realities
Sure, you can design a great-looking map on paper, but can you get a computer to do it?
systems vary greatly in their strengths and weaknesses: be aware of both
when selecting a mapping system, consider availability of needed functions and ease of use
be aware of the problems of designing for particular output devices
experimentation and multiple iterations are often required
never trust defaults: