Designing Maps

GTECH201Lecture 19

Yet Another Definition “A graphic depiction of all or part of a

geographic realm in which the real-world features have been replaced by symbols in their correct spatial location at a reduced scale.”

Cartographic Design Principles

Audience and purpose

Size, scale, and media

Visual balance

Audience and Purpose

Size, Scale and Media

Visual Balance

Elements of a Map

Map body Legend Title Scale North arrow (inset map)

Other Elements of a Map

Source of data Map projection Author Date Neatline Graphs, tables, images, informative

text ..leading towards a poster

Who Made It?

What is its name?

Legend

Where is it located (inset)?

Where is north

What is the scale/

How accurate is it and where can you get it?

•Credits.•How was it made.•Projection and Datum.

•Other metadata

UTM??

Coordinates in DD

Border

Neatline?

Map Templates

Layer Transparency

Labels and Annotation

..more later today

Reference System Graticule ºN/S, ºE/W Measured grid X, Y Reference grid 12B or 14G

Map Layout Templates again

Map Scale

The ratio of the distance between two points on the map and the distance between the same two points in the real world

Describes distances and area sizes

Why Do We Care About Scale

To compare or edge-match maps, they must be in the same GCS

Remember, a GCS consists of: A metric An origin A projection A datum

Types of Scale

Graphical

Phrase (word(y) statement)

Representative fraction

Special cases

Variable scale

Graphical Scale

Changes in map size(copy machine) preserve scale relationships

Unit independent

Verbal Scale

Does not preserve scale with size change

Unit-dependant

One inch equals one mile One to a a mile

Representative Fraction

Does not preserve scale in size change Unit independent Ratio is true regardless of units Expressed as a ratio 1:100,000 Expressed as a fraction

1/100,000

Variable Scale

Projections that do not preserve distance

City maps (Falk)

Large vs. Small Scale

Small scale shows large areas Large denominator Think of it as small in detail

Large scale shows small areas Small denominator Think of it as large in detail

1/500,000

1/500

Area and Scale

Retains the same relationship as linear scale

The linear scale is squared

1:1,0002 equals 1:1,000,000

One square inch to one square mile

Examples of Scale

You Have to Decide

What is the intended use

How will it be used

How much detail

What are the units

Linear Units

Metric Kilo-, centi-, milli-meters

SAE Miles, yards, feet, inches

Other Degrees, chains, furlongs, rods, light-

years

Unit-less

Areal Units

Metric Hectare, decare, are

U.S. Public Land Survey Township, section, acre

Other City block, ZIP code, police district,

parsec

Unit-less

Convenient Fractions

Metric 1 / 100,000 or 1 cm equals 1 km

SAE 1 / 63,360 or 1 inch equals 1 mile

U.S. topographic maps 1 / 24,000 or 1 inch equals 2,000 feet

Metric / SAE ConversionLeague 1

Mile 3

Furlong 24

Chain 240

Rod 960

Yard 5280

Foot 15,840

Link 24,000

Hand 47,520

Inch 190,100

Line 2,281,000

Kilometer 4.828

Meter 4,828

Centimeter

482,800

Millimeter 4,828,000

Beware of

1 / 100,000 does NOT mean 1 mm equals 1 km, or 1 inch equals 100,000 feet

Mixed units Not allowed in representative fractions Permitted in verbal usage

Resolution

What is it that you wish to represent Countries States Counties Towns Property ownership

Detail

How much information needs to be conveyed?

How precisely have objects to be mapped? Generalization Cartographic license

Cartographic License

Alteration of real-world spatial relations to better present pertinent information

Distortion

Combination

Shift

Exaggeration

How Much Detail?

Road Displacement

Generalization

1:5,000 1:10,000