GIS Clarke Cartography

7/31/2019 GIS Clarke Cartography

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Making MapsWith GIS

Lecture 8[based on Chapter 7]

(minor edits by Sharma UQ)


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7 Making Maps with GIS

7.1 The Parts of a Map 203

7.2 Choosing a Map Type 206

7.3 Designing the Map 210


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What is a map?

A graphic depiction of all or part of a

geographic realm in which the real-world

features have been replaced by symbols intheir correct spatial location at a reduced

scale.

power line


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Map function in GIS

Storage

Communication (temporary/permanent)

Intermediate check of data

Final report

To be effective, must be correctly designed

and constructed.


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The Parts of a Map: Map Elements

The United States of America

Alaska

Lambert Conformal Conic ProjectionSource: U.S. Dept. of State

0 41 2 3

hundreds ofkilometres

0 4 04

Washington,D.C.National Capital

Legend

Scale

CreditsNorth ArrowPlace nameInset

Ground

Figure

Neat line Border Title

Hawaii


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The medium is the message

Paper

Film

Mylar

Monitor

Projection

Broadcast TV THE DISPLAY IS PART OF THE

SYMBOLIZATION


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Cartographic Elements

Medium

Figure

Ground

Reference information


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Cartographic Elements (2)

Border

Neatline

InsetsScale up

Scale down

Metadata e.g. index

Off-map references


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Page coordinates

Ground elements

Graticule/Grid

North arrow


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Figure

Point/Line/Area symbols

Text

Place Names

Title


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Reference Information

Scale

Projection(s)

Sources (2)

Credits

Legend

Reliability


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Map impact

Distribution of Employment by State 1996

United States: Employment Distribution

1996 U.S. Employment: 1996 Distribution

America at Work

Where the Jobs are Today


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Choosing Elements

Map research

Map compilation

Worksheet

Selection

Placement

Layout Tools in GIS not ideal


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Choosing a Map Type

Cartographers have designed hundreds of

map types: methods of cartographic

representation. Not all GISs allow all types.

Most have a set of basic types

Depends heavily on the dimension of thedata to be shown in the map figure.


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Choosing the Wrong Type

Fairly common GIS error.

Due to lack of knowledge about

cartographic options. Can still have perfect symbolization.

Possibility of misinformation

Definite reduction in communicationeffectiveness.


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Map Types: Point Data

Reference

Topographic

Dot

Picture Symbol

Graduated Symbol


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Map Types: Line Data

Network

Flow

Isopleth

Reference


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Map Types: Area Data

Choropleth

Area qualitative

Stepped surface

Hypsometric

Dasymetric

Reference


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Map Types: Volume Data

[Isopleth, Stepped Surface, Hypsometric]

Gridded fishnet

Realistic perspective

Hill-shaded

Image map


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Map Types: Time

Multiple views

Animation

Moving mapFly through

Fly by


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Choosing Types

Check the data

Continuous

Discrete

Accuracy & Precision

Reliability

Dimension (Point, Line, Area, Volume)

Scale of Measurement (Nominal etc.) GIS capability May need to supplement GIS software


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Data Scaling (Stevens)

Nominal (Name of a place)

Ordinal (Small, med., large town)

Interval (Arbitrary zero e.g. Sea Level)

Ratio (Absolute zero e.g. dollars, densities)


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Example: Choropleth Mapping

Data should be AREA (e.g. States)

Data should not suffer from area effect.

Population?

Per capita Income?

Elevation? Temperature?

Boundaries unambiguous.

Areas non-overlapping.


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Classification

Equal Interval

Natural groups

N-tiles

Equal or unequal?

Logarithmic? Linear? Discontinuous?

How many classes?

Non-overlapping, distinctive groups.


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The Need for Design

To appear professional and avoid errors,

GIS maps should reflect cartographic

knowledge about map design.

A map has a visual grammar or structure

that must be understood and used if the best

map design is desired.

Cartographic convention (e.g. forests shouldbe green).


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Map Design

A GIS map is designed in a process called

the design loop.

Good map design requires that mapelements be placed in a balanced

arrangement within the neat line.


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The Design Loop

Create map layout (macro ?)

Draw on screen (proof plot)

Look/evaluate

Edit macro

Repeat until happy

Make final plot


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Graphic Editors


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Graphic Editor Software

Vector

Adobe Illustrator

CorelDrawFreehand

Raster

PaintShop Pro, Photoshop

CorelPaint

Fractal Paint


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Map Design (2)

Visual balance is affected by:

the "weight" of the symbols

the visual hierarchy of the symbols andelements

the location of the elements with respect to each

other and the visual centre of the map.


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Visual centre

5% of height

5% of height

Landscape Portrait


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Visual Layout

Title Here

Title Here

Eye expects (1) balance and (2) alignment


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Symbol weight

Line weight Pattern Shading Hue


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Colour and Map Design

Colour is a complex visual variable and in a

GIS is specified by RGB or HSI values.

Red, Green, Blue are additive primaries. Magenta, Cyan and Yellow are subtractive

primaries.

Saturation and Intensity map better ontovalues than hue.


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Dimensions of Colour

HUE

SATURATION

INTENSITY


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Simultaneous Contrast


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Colour Primaries

Subtractive colour Additive colour


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Text placement

Santa Barbara

Santa Barbara

Santa BarbaraSanta Barbara

L a g o o n

Path right

P

a

t

h

D

o

w

n


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Scale and Generalization

Smaller scale means fewer features.

Smaller scale means smoother features.

Smaller scale means combining features. Smaller scale means displacing features.

Often scales are mixed or overgeneralized.


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Map Design and GIS

When a GIS map is the result of a complex

analytical or modelling process, good

design is essential for understanding. The map is what distinguishes GIS as a

different approach to the management of

information, so extra care should be taken

to improve the final maps that a GIS

generates in a GIS task.

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