What is a map?

Objectives of lecture

Expectations for the class
Define cartography and maps
Components of map information: time, space, and attributes

360: The Course

Introducing the 360 Team:

Instructor: Nick Chrisman

Teaching Assistants: Fred Dent (unrelated to author of text), Steve Hyde, Muthatha Ramanathan

Expectations

A learning environment for cartography: Learning Objectives

Syllabus: lectures, readings, labs, deadlines, grading...

Defining Cartography

Cartography: the art and science of making maps (International Cartographic Association)
"A map is a graphic representation of the milieu." (cultural and physical environment)

[both definitions so broad that it doesn't help much...]

Varieties of maps...

Reference maps : serve as base maps, record what is there, general purpose
emphasis on geometric properties distance, direction, area
some are not specifically interpreted (as air photographs)
some (eg. topographic maps, nautical charts) are highly symbolic
Thematic maps : special purpose, emphasis on single "theme" not position
extreme form of thematic maps cartograms distort geometry on purpose

Each of these is a "genre", a formalized arrangement of expectations about how the signs work. [The tools of thematic cartography can be used to build a reference map with many "layers".]

Two 'schools' of cartography:

Communication: (Dent, Robinson, most of the rest) map as communication channel between map designer and map reader (percipient). Focus on visualization, cognition.
Analytical: (Tobler, Nyerges, Chrisman, few others) map as transformation of information. Focus on structure of information content.

Mapping as a process of abstraction:

The "Real World", in all of its diversity is viewed with a specific purpose in mind.
A system of symbols portray the information (originally graphics symbols, now also data structures)
Transformation that restructures source material to make a map:
The World is compressed - represented by the map.
(from Erwin Raisz, 1962, Principles of Cartography, chapter 3)

1 Maps are drawn in a predetermined scale.
2 Maps are selective, based on purpose of map.
3 Maps emphasize certain of selected features (themes)
4 Maps are symbolized.
5 Maps are generalized. Intricate detail is simplified.
[ 6 Maps are lettered, titled and labelled.
7 Maps are usually related to a reference system] List applies to databases?

Ways to look at the World:

Basic choices - What exists?
Bare geometry as one conceptual filter: points, lines, areas and volumes...
Strawperson: "Map as mirror", simply reflects "reality"

The complete mapping process

A process of communication: Concepts, facts transmitted through the map

Data collection (followed by selection, processing, transformation)

Map construction (encode the information for a particular purpose)

Map Use the encoded message does no good unless it can be used...

Map Reading deciphering symbols (relating to intended message)

Map Analysis construct spatial patterns and relationships
(a process of structured map reading, measurement...)

Map Interpretation link spatial form & patterns to causation (process)

BUT this is nowhere near as linear as it sounds!

Map makers, readers, users are all surrounded by a lot of pre-existing social cultural arrangements that communicate meaning...

lots of map use is directly by the map maker, an aid to thinking, not arms-length communication (in a more private realm: MacEachern Exploration, Confirmation, Synthesis, Presentation)

Map as inventory, repository of spatial facts and arrangements (database)

Communities of Practice develop (disciplines) to set expectations that don't need to be communicated... The insiders KNOW what will be on the map. Outsiders beware.

Field of Semiotics (the study of signs-symbols) distinguishes

referent (thing in the world),
sign (symbolic representation),
interpretant (the one who makes the connection between the other two?)

Multiple versions of this triangle with each connection emphasized...

Not necessarily the linear message transmission of communication theory (Shannon & Weaver, telephones, digital transmission, etc.)
Succinctly: "the map is not the territory" (Count Korzibski)
Some read maps as an expression of political (economic, etc.) power.

Basic agreement:

Multiple maps can be made of the same place
Maps can "have" (present, represent...) a point of view
Readers (users, interpretants) have to pay attention

Good maps:

Is a map just to be judged by its correspondence to the world? (according to whose rules?)

Or is a map just an element of technology that does a "job"?

Or does this difference sound too much like splitting hairs?

Perhaps the most important function of a map:

As an "inscription", it makes the world portable... (you can move it around without changing what you wrote down)

Components of map information:

Time, Space, & Attributes
Role of "Reference Systems" to position in Time (calendar, clock), Space (geodetic position), and Theme

Attributes are the "content" delivered in the wrapping of their reference to time and geometry.

[also called "theme": thematic 'overlay' adds content to the base geometry]

Many relationships can be formed (measured, represented, extracted ...)

Location1 => Location2 distance, bearing, geometric relationships
L1 (Attribute1, A2, ...) relationships between attributes at one "place" [and one time]
L1 (A1) => L2 (A1) relationships between attributes at different places/times

Version of 28 March 2003