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: